ORCID Profile
0000-0002-4187-616X
Current Organisations
King Saud bin Abdulaziz University for Health Science
,
Swinburne University of Technology
,
Nanyang Technological University
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Publisher: Elsevier BV
Date: 05-2023
Publisher: Elsevier BV
Date: 10-2010
Publisher: Inderscience Publishers
Date: 2009
Publisher: Elsevier BV
Date: 06-2010
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 2007
Publisher: Elsevier BV
Date: 1993
Publisher: Elsevier BV
Date: 1997
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.535-536.94
Abstract: The aim of this paper is to investigate the effect of the gradient on the cross-section on the dynamic behavior of the graded cellular rods under impact loading. A graded cellular rod, whose cross-section varies along the axial direction, is supposed to impinged by a rigid mass G with initial velocity . The shock theory proposed by Reid and Peng [1] is employed to establish the analytical model. Similar to the previous work [2], the analytical results show that only one shock front appears when the gradient is positive while two shock fronts exist in the rod with negative gradient. Closed form solution is found for the single shock (SS) mode, while finite difference method is employed to obtain solutions for the double shock (DS) mode.
Publisher: Elsevier BV
Date: 09-2023
Publisher: Springer International Publishing
Date: 2015
Publisher: Elsevier BV
Date: 06-2020
Publisher: SAGE Publications
Date: 04-11-2014
Abstract: In this paper, an analytical method is presented to solve the scale effect on migration motion and coalescence of void in piezoelectric solid subjected to gradient stress and electric filed. The piezoelectric solid is considered as an infinite orthotropic piezoelectric film corresponding to the scale of void. The surface diffusion of void in piezoelectric film is taken as the dominant mechanism for the migration motion of the void. Based on the non-local elastic theory considering the interact force among atoms, the influences of small-scale parameter, stress gradient, stress state, electric loading, and shape of void on the migration motion coalescence of void in piezoelectric film are described.
Publisher: Elsevier BV
Date: 05-2017
Publisher: Elsevier BV
Date: 2008
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 05-2010
Publisher: SAGE Publications
Date: 04-2002
Abstract: This paper concerns the large deflection of elastoplastic, non-linear strain-hardening cantilevers of rectangular cross-section, for which the stress-strain relationship after yielding is described by σ= K 1 ε q . Both the bending moment and axial force are included in the yielding criterion, and the corresponding strain increments obey the associated normality rule. Comparisons between the experimental data and the theoretical predictions are made for mild steel cantilevers subjected to a tip force with an inclined angle ϕ = 67.5,90 and 157° respectively. Reasonable agreement is obtained. The theoretical analysis has described the large deflection behaviour of the cantilever and is in good agreement with tests.
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 02-2014
Publisher: Springer Science and Business Media LLC
Date: 08-07-2008
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 02-1996
Publisher: SAGE Publications
Date: 18-11-2015
Abstract: The dynamic failure of fibre metal laminates was investigated experimentally. A projectile of hemispherical head with a diameter of 36.5 mm was used to impact the fibre metal laminate panels. Three types of woven fibre fabrics (Basalt, S2-glass and Kevlar-29) were used to reinforce the aluminum sheets. Tests on these fibre metal laminate panels were conducted by using an aerodynamic gun with the impact velocity ranging from 20.6 m/s to 42.8 m/s. Different deformation/failure modes of fibre metal laminates were obtained by varying the impact energy. The failure mechanisms of composite layers were examined by the field emission scanning electron microscope. The results showed that before the fibre metal laminate panels were penetrated, the global deformation increased with the impact velocity. However, evident reduction of global deformation can be observed after penetration occurred. Damages of fibre metal laminate panels such as tearing of aluminum ply, fibre fracture, matrix cracks and debonding/delamination were observed around the impact region. The results indicate that basalt reinforced aluminum laminates perform well in terms of impact resistance and offer significant potential in engineering applications.
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 2020
Publisher: World Scientific Pub Co Pte Lt
Date: 06-2016
DOI: 10.1142/S1758825116500435
Abstract: Strain rate is essential in study of the physics of fluids and solids undergoing deformation. State-of-art high strain rate tests have mainly been in macro-scale with an upper limit of [Formula: see text]. A graphene-based layered system is proposed to conduct nanometer-scale high strain rate testing. The process is investigated by molecular dynamics simulations. Accelerated single ion or group of ions are used to impact on the proposed system to generate ballistic or plate-like impact scenarios. The effects of impact energy, shape of impact absorber and the impaction location are investigated. The graphene layer is the key of the proposed system to spread the load and protect the s le. The results indicate that ion group and single ion impacts produce strain rates of [Formula: see text]–[Formula: see text] and [Formula: see text]–[Formula: see text], respectively. Ion group impact produces a more significant signal than single ion impact on the sensing nano-layer in the system. The ultimate strength of an Al-Cu alloy s le during ion impact is estimated to be 215[Formula: see text]MPa to 251[Formula: see text]MPa, significantly lower than predicted by the Johnson–Cook model because of the rapidly increased temperature and melting in the s le. The results demonstrate new possibilities for understanding high strain rate effects at nano-scale.
Publisher: Elsevier BV
Date: 12-1994
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 04-2013
Publisher: Wiley
Date: 30-04-2014
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 02-2002
Publisher: Elsevier BV
Date: 12-2014
Publisher: Springer Science and Business Media LLC
Date: 1999
Publisher: Elsevier BV
Date: 03-2015
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 08-2008
Publisher: Elsevier BV
Date: 07-2018
Publisher: IOP Publishing
Date: 09-2017
Publisher: SAGE Publications
Date: 03-2003
DOI: 10.1177/0731684403022005492
Abstract: An investigation is carried out to understand the non-linear thermal buckling behaviour of local delamination near the surface of fiber reinforced laminated plates. The shape of the delaminated region considered is rectangular, elliptic or triangular. The mechanical properties and the thermal expansion coefficient of the fiber material are treated as a function of temperature, which leads to the force in the middle plane of the laminated plates a non-linear function of temperature. The critical temperatures of laminated plates with variously shaped local delamination and different stacking patterns are obtained by making use of the energy principle. It has been found that linear solutions of the critical buckling temperature give a higher value than that from non-linear consideration.
Publisher: Informa UK Limited
Date: 06-2013
Publisher: IMPERIAL COLLEGE PRESS
Date: 2014
Publisher: Elsevier BV
Date: 04-1995
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 07-2002
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 07-2023
Publisher: Elsevier BV
Date: 2018
Publisher: Springer Berlin Heidelberg
Date: 2010
Publisher: Springer Science and Business Media LLC
Date: 12-12-2007
Publisher: Wiley
Date: 15-06-2012
Publisher: Elsevier BV
Date: 04-2019
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.535-536.522
Abstract: The strength enhancement of cellular materials under dynamic compression was experimentally studied in the present paper. A phenomenological model was employed to investigate the entrapped air contribution by introducing a parameter, namely the leaking rate of air. The strength enhancement caused by the entrapped air was then studied for both aluminum honeycombs and foams. It has been found that the pressure change in the entrapped air during dynamic compression is a direct source of strain hardening for aluminum honeycombs whereas it has smaller influence on the strain hardening of aluminum foams. Other sources that might contribute to the strain hardening of cellular materials are also discussed.
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.JBIOMECH.2012.08.037
Abstract: The viscoelastic properties of the living cells are for quantifying the biomechanical effects of drug treatment, diseases and aging. Nanoindentation techniques have proven effective to characterize the viscoelastic properties of living cells. However, most studies utilized the Hertz contact model and assumed the Heaviside step loading, which does not represent real tests. Therefore, new mathematical models have been developed to determine the viscoelastic properties of the cells for nanoindentation tests. Finite element method was used to determine the empirical correction parameter in the mathematical model to account for large deformation, in which case the combined effect of finite lateral and vertical dimensions of the cell is essential. The viscoelastic integral operator was used to account for the realistic deformation rate. The predictive model captures the mechanical responses of the cells observed from previous experimental study. This work has demonstrated that the new model consistently predicts viscoelastic properties for both r ing and stress relaxation periods, which cannot be achieved by the commonly used models. Utilization of this new model can enrich the experimental cell mechanics in interpretation of nanoindentation of cells.
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 09-2010
Publisher: Informa UK Limited
Date: 02-2011
Publisher: Trans Tech Publications, Ltd.
Date: 08-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.626.383
Abstract: Cellular material such as aluminium foam has been considered as a potential material for energy absorption upon impact and blast loadings. One of the most important properties that contribute to this feature is the densification strain. At high impact velocity, prediction of the densification strain from quasi-static engineering stress-strain curve has been found inadequate. Furthermore, theoretical prediction using the equation proposed by Reid et al. always over-predicts the dynamic crushing stress. Formation of the shock wave at high impact velocity is believed to further increase the densification level of the foam. However, this effect is disregarded when determining the densification strain quasi-statically. The present study aims to address this issue by determining the densification strain experimentally from impact tests. Forty cylindrical aluminium foams with three different lengths were used as projectiles and were fired towards a rigid load cell by using a gas gun. The peak forces generated from the impact were recorded and analysed. The experimental densification strains were determined physically by measuring the deformation of the foam projectiles after the tests. It is concluded that, at high impact velocity, the densification strain varies with the initial impact velocity. Therefore an appropriate value of densification strain needs to be used in the equation of dynamic crushing stress for a better approximation.
Publisher: EDP Sciences
Date: 2015
Publisher: Elsevier BV
Date: 07-2019
Publisher: SAGE Publications
Date: 12-2011
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 05-2020
Publisher: Springer Science and Business Media LLC
Date: 14-01-2019
Publisher: Elsevier BV
Date: 09-2001
Publisher: Elsevier BV
Date: 05-2012
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 05-2007
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 02-2003
Publisher: Elsevier BV
Date: 11-2003
Publisher: Elsevier BV
Date: 12-2015
Publisher: Thomas Telford Ltd.
Date: 04-2003
DOI: 10.1680/MACR.2003.55.2.183
Abstract: The dynamic characteristics of steel fibre reinforced concrete (SFRC) have been obtained through 75 mm diameter split Hopkinson pressure bar (SHPB) tests. In order to understand the intrinsic dynamic behaviour of the material, this paper reviews the SHPB testing technique, and presents the principles and limitations of the equipment. Using a linear-shaped striker bar, a half-sine incident loading waveform is generated which eliminates attendant problems such as non-uniform stress distribution and wave oscillation. Following the verification of the SHPB equipment, a number of dynamic uniaxial compression and tension splitting tests were conducted on SFRC specimens. The influence of strain rate on the response of SFRC specimens is presented. Results indicate that dynamic uniaxial compressive strength of SFRC increases moderately at relatively high strain rate, and the tensile splitting strength increases many times at moderate strain rate loading compared with its static value. Further, the stress–strain relationship of SFRC does not exhibit the ductility that is evident when the material is tested at static load condition.
Publisher: SAGE Publications
Date: 14-12-2016
Abstract: To study the protection property of aluminum alloy sandwich panels with honeycomb cores under the attack of bullets or debris, quasi-static perforation, and ballistic impact tests were conducted, in which the thicknesses of the face sheet and core were 0.5–2.0 and 12.7 mm, respectively, while projectiles with diameter 7.5 mm and impact velocity 50–220 m/s were employed. Based on the experiments, the influences of impact velocity, face sheet thickness, core density as well as the nose shape of the projectiles were investigated. The results showed that in the impact tests, the sandwich panels dissipated much more energy than those in quasi-static perforation tests, and the energy absorption and ballistic limit of the sandwich panels increased with the increase of impact velocity. The influence of face sheet thickness was more remarkable than the core density, which was due to the relative density of honeycomb is too small. Although the increase of core density could induce the increase of energy absorption, this effect is more effective for thinner face sheet. Moreover, under the same impact velocity about 200 m/s and face sheet thickness 1.0 mm, the ballistic limit for conical-nosed projectile is highest, while it is lowest for flat-nosed projectile.
Publisher: IOP Publishing
Date: 17-07-2013
Publisher: Springer Science and Business Media LLC
Date: 12-06-2015
Publisher: AIP Publishing
Date: 18-12-2017
DOI: 10.1063/1.5005553
Abstract: We design a 3D acoustic metamaterial having a coiling resonant structure with high symmetry. Eigenstate analysis reveals that such a 3D metamaterial has two significant Mie-type eigenmodes, monopole and dipolar resonances. Large blocking of sound waves in the low-frequency range between monopole and dipolar resonances is observed numerically and experimentally. The effective properties extracted from the reflection and transmission coefficients show negative bulk modulus around the monopole resonant frequency and negative mass density around the dipolar resonant frequency. By employing the proposed two-scale model, the metamaterial system demonstrates the functionalities of sound cloaking and super-tunneling within a finite space.
Publisher: SAGE Publications
Date: 12-2010
DOI: 10.1260/2041-4196.1.4.507
Abstract: Cellular metals with stochastic, 2D or 3D periodic microstructures can sustain large plastic deformation at almost constant stress. Due to such excellent energy absorption capability, cellular metals are very suited to be used as the core of sandwich structures, which have been applied widely to the areas of aerospace and aeronautical design, the automotive manufacturing, and shipbuilding, as well as the defense and nuclear industries. Although there is a great deal of research currently available related to the behaviour of sandwich structures with metallic cellular core under various loading conditions, they are widely scattered in the literature. This review paper brings together the latest developments in this important research area. Three types of cellular metals, namely metal foams, honeycombs and prismatic materials and truss and textile based lattice materials are considered. The responses of sandwich structure with such cores subjected to different loads, i.e. quasi-static/low velocity compression and indentation, ballistic impact, high speed compression and blast loading, are reviewed. The emphasis has been placed on their plastic deformation, failure and energy absorption behaviours.
Publisher: Elsevier BV
Date: 2016
Publisher: FapUNIFESP (SciELO)
Date: 2014
Publisher: Elsevier BV
Date: 07-2017
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 08-2013
Publisher: American Society of Mechanical Engineers
Date: 18-08-2019
Abstract: In this paper, quasi-static out-of-plane compression behaviors of Miura-ori patterned sheets were investigated numerically by using finite element analysis (FEA). The simulation results show a reasonable agreement with the experimental results. In addition, the parametric analysis of the Miura-ori patterned sheets with different cell wall thicknesses, side lengths, dihedral angles and sector angles were carried out using FEA method. The influences of different parameters on the peak force and mean force were determined.
Publisher: Elsevier BV
Date: 10-2001
Publisher: Elsevier BV
Date: 07-2005
Publisher: Elsevier BV
Date: 06-2010
Publisher: Elsevier BV
Date: 07-2021
Publisher: American Society of Civil Engineers (ASCE)
Date: 07-2022
Publisher: Inderscience Publishers
Date: 2005
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.535-536.457
Abstract: This paper examines a projectile impact on a fully cl ed sandwich beams with foam core. By modeling the sandwich beam into two perfect rigid-plastic beams connected by perfect rigid-plastic springs, different coupling mechanism for the responses of the two beams are constructed so that a complete solution considering small deformation is derived.
Publisher: SAGE Publications
Date: 05-2020
Abstract: The load-carrying capacity of the symmetrical and asymmetrical sandwich beams, under a quasi-static central load, is investigated in this paper. Three collapse mechanisms such as face yield, core shear and indentation are considered for symmetrical sandwich beams. Core shear mechanism is taken into account for fully cl ed asymmetrical sandwich beams. Continuity equations are established by simple ‘equal area’ method for the postyield behavior of the sandwich beams in face yield and core shear mechanisms at different boundary conditions. In indentation mechanism theoretical model, the effect of the local denting on the large deflection of the sandwich beam is taken into account. Then, finite element simulations are carried out to verify the validity of the proposed analysis, and a good agreement is presented. It is shown that in the core shear mechanism under fully cl ed condition, no plateau phase is presented. The effect of the core thickness on the response of the symmetrical beams is discussed in detail. For asymmetry beams in core shear mechanism under fully cl ed condition, the effect of the asymmetric factor (strength or thickness) for face-sheets on the load–deflection behavior of the postyield beams can be neglected, if the sum of the strength or thickness of the face sheets is constant.
Publisher: Springer Science and Business Media LLC
Date: 12-1996
DOI: 10.1007/BF02328581
Publisher: Oxford University Press (OUP)
Date: 11-04-2013
DOI: 10.1093/CID/CIT230
Publisher: Springer Science and Business Media LLC
Date: 16-06-2023
DOI: 10.1007/S10338-023-00405-Z
Abstract: The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations. The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and shear loading were analyzed using the relative density as a governing parameter. The non-unique relationships between the core density and the materials’ strength in the examined loading directions were revealed, pointing out the strong influence of the Miura-ori topology. Linear relationships were established between the elastic moduli and relative densities of the Miura-ori metamaterials while power-law functions of the relative density with different exponent constants were established for the strength in different loading directions. It was shown that the Miura-ori materials possess the highest strength under shear in the $${X}_{1}-{X}_{3}$$ X 1 - X 3 plane and it increases with the increase in the relative density. However, this characteristic is strongly influenced by the sector angle $$\\alpha $$ α . In general, the difference between the two shear strengths increases when increasing the relative density by using thicker cell walls. It is noted that the strength of the Miura-ori materials as a function of the relative density is nearly constant with respect to the cell dimensions if the values of folding angle $${\\gamma }_{0}$$ γ 0 and sector angle $$\\alpha $$ α are given. The mechanical characteristics of the Miura-ori material with equal relative density, which exhibits the highest strength among the analyzed origami models, are compared with the out-of-plane compression and shear responses of prismatic hexagonal honeycomb. It is observed that compression and shear responses of the honeycomb outperform the Miura-ori foldcore in all loading directions when considering large deformations.
Publisher: Springer Science and Business Media LLC
Date: 14-03-2019
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 05-2003
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 11-2023
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2011
Publisher: Informa UK Limited
Date: 14-09-2013
Publisher: Wiley
Date: 17-12-2019
Publisher: Hindawi Limited
Date: 04-2020
DOI: 10.1002/ER.5181
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 03-1993
Publisher: Elsevier BV
Date: 02-2000
Publisher: Trans Tech Publications, Ltd.
Date: 08-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.626.127
Abstract: Aluminum honeycombs are lightweight and have good energy absorption capability. They are widely used in industrial products and also as core materials in various fields of engineering such as aerospace, automotive and naval engineering because of their high specific strengths and they can undergo large plastic deformation to absorb high impact energy. In the applications of aluminum honeycombs they are not only subjected to pure compressive or indentation load but sometime also under combined compression-shear load. The mechanical response and crushing behavior under combined compression-shear loading condition is still limited in literature. In this paper, quasi-static out-of-plane combined compression-shear tests were conducted to study the deformation mechanism of different types of HEXCELL® aluminum honeycombs with different cell sizes and wall thicknesses. Three types of aluminum honeycombs were used in this study. A universal MTS machine with specially designed fixtures was employed in the quasi-static loading tests. The experiments were conducted at three different loading angles, that is, 30°, 45° and 60° and in TL and TW (T is out-of-plane direction and L, W are the two in-plane directions) plane orientation loading directions of aluminum honeycomb. The effects of different loading angle and different plane orientation are reported in this experimental study. Similarly, the effects of cell size and cell wall thickness were also analyzed.
Publisher: BMJ
Date: 14-05-2013
Publisher: Oxford University Press (OUP)
Date: 20-04-2023
DOI: 10.1093/BJS/ZNAD092
Abstract: Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling reducing use of anaesthetic gases and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices reducing use of consumables and reducing the use of general anaesthesia. This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries.
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 2018
Publisher: SAE International
Date: 03-1994
DOI: 10.4271/940057
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 06-2003
Publisher: ASMEDC
Date: 6
Abstract: Aluminium foam is a type of cellular materials and offers potential for lightweight structures and energy absorbers in automotive and aerospace industries. They may be subject to multiaxial loads in these applications and it is essential to have a failure criterion in terms of the stresses which cause yield. Three criteria have been proposed so far. Gibson and Ashby deduced a yield surface by using dimentional arguments for ideal, isotropic, homogenous foams. Miller’s yield surface was based on the model of Drucker and Prager, which was originally proposed as a model for soil. It incorporated a linear and quadratic dependence on the pressure. Deshpande and Fleck modified the yield criterion of solid metals to account for the effect of porosity on the yield criterion for a metallic foam. In this paper, triaxial tests of CYMAT aluminium foams were conducted by using MTS (Mechanical Test System) with a Hoek Cell to investigate their yield surfaces experimentally. Five types of aluminium foams with nominal relative densities. of 5%, 10%, 15%, 17% and 20% were tested for a range of axisymmetric compressive stress states. Experimental results were compared with three theoretical criteria. Triaxial tests at various strain rates (from 10−4 to 10+1 s−1) were also performed in this paper to investigate the influence of strain rate on the yield surface.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2019
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.794.194
Abstract: Fibre-reinforced composite materials and structures have been extensively used as energy dissipating components in industries. The crashworthiness of square and circular CFRP (Carbon Fiber Reinforced Plastics) tubes have been widely studied. This paper investigates the deformation and energy absorption of square CFRP frusta under axial quasi-static crushing. The effects of various geometry parameters such as height-to-mean width (H/B) and thickness-to-mean width (t/B) ratios on the crushing resistance for square CFRP frusta with an apical angle of 10 ° have been examined experimentally. Finally the crashworthiness metrics of square CFRP frusta and square tube are compared and evaluated. The results show that the experimentally observed deformation mode of CFRP square frusta can be classified into three types, namely progressive folding collapse splaying crushing mode characterized by a combination of progressive splaying and transverse shearing failure and transition mode respectively. The initial peak force, mean crushing force and energy absorption of square CFRP frusta deformed in splaying mode increase with the increasing of wall thickness and width. For the desirable progressive splaying mode, three energy dissipated mechanisms have been identified as crack propagation, transverse shearing and friction energy.
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2015
DOI: 10.1142/S1758825115500866
Abstract: Laminated multiple metal or alloy sheets have been widely used in protective structures. However, energy absorption mechanism remains unclear for those laminates with different interface and surface conditions under low-velocity impact. This study investigates the effect of interface and surface modified double aluminum sheets under drop-weight loading. The experimental results showed that epoxy-bonded double sheets did not dissipate more energy than free-contact s le. The simulation results agree well with the experimental data at low cohesive stress of the epoxy adhesive, and friction plays an important role in absorbing impact energy for free-contact s le. However, at high interface cohesive stress as simulated, epoxy-bonded s les absorb more energy than free-contact ones. Further experiments indicated that s le with grease spread front surface is more sensitive in improving energy absorption than s le with grease applied in between two layers. These results are important reference for designing laminated composites to improve impact resistance.
Publisher: IEEE
Date: 2006
Publisher: Trans Tech Publications, Ltd.
Date: 08-2015
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.626.57
Abstract: Abstract. This contribution presents the investigation of energy absorption mechanism of metal tubes and composite-wrapped metal tubes subjected to a diametric deformation via an expansion process. In the experiments, the expansion of the tubes was performed under quasi-static loading using a conical-cylindrical expansion die. The experimental results are repeatable and thus reliable. An extensive finite element analyses and experimental investigation were carried out in parallel. Both two-dimensional and three-dimensional finite element models were created based on the actual experimental geometrical and material parameters. Results from the finite element analyses correlate rather well with the experimental data. Glass fibre-wrapped metal tubes showed an increased steady-state reaction force which in turn reflects better specific energy absorption capacity for every layer of composite wrapped as compared to bare metal tubes.
Publisher: Elsevier BV
Date: 03-2018
Publisher: Trans Tech Publications, Ltd.
Date: 07-2017
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.744.317
Abstract: The aim of this study is to find the best platen with blades as a new energy dissipating mechanism that causes considerably damage to CFRP/aluminium tubes. Specially designed and manufactured platens with five different cutting blade profiles were used to simultaneously cut and crush square CFRP tubes and aluminium sheet-wrapped CFRP tubes. The platens with blades were evaluated in terms of the deformation mode, mean crushing force, energy absorption and specific energy absorption of tubes. Experimental results showed that tubes cut and crushed by the platen with 45 o inclined blades had the best crushing performance and exhibited a more stable deformation mode compared with those for tubes cut and crushed by other platens with different blade profiles. The platens with blades acted as trigger mechanisms that minimise the initial peak crushing force and maximise the energy absorption of tubes compared with tubes crushed by flat loading platens.
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 12-2010
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 1990
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier BV
Date: 02-2021
Publisher: SAGE Publications
Date: 07-1993
DOI: 10.1243/PIME_PROC_1993_207_126_02
Abstract: A study of the behaviour of C channel under pure bending applied in such a way as to create compressive stress at the tip of the webs is presented. The analysis encompasses the entire loading history of the beam, from the linear elastic stage, through the buckling of the webs, to the unloading stage after the formation of a plastic hinge. The theoretical predictions were compared to the test results of a series of seven beams. Close correlation was found between theory and experiment over the entire loading range explored, especially for sections with a width-thickness ratio of less than 50.
Publisher: Elsevier BV
Date: 05-1999
Publisher: Elsevier BV
Date: 02-2002
Publisher: MDPI AG
Date: 04-03-2016
DOI: 10.3390/MA9030162
Publisher: Elsevier BV
Date: 07-1994
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 12-2002
Publisher: Elsevier BV
Date: 11-2021
Publisher: FapUNIFESP (SciELO)
Date: 02-2017
Publisher: Elsevier BV
Date: 2017
Publisher: SAE International
Date: 12-04-2010
DOI: 10.4271/2010-01-0020
Publisher: Wiley
Date: 17-04-2017
DOI: 10.1002/TAL.1375
Publisher: Elsevier BV
Date: 02-2012
Publisher: Elsevier BV
Date: 03-2013
Publisher: Elsevier BV
Date: 07-2014
Publisher: World Scientific Pub Co Pte Lt
Date: 10-01-2013
DOI: 10.1142/S0219519413500152
Abstract: The general behavior of wave propagation in liposomes, including the effect of rotary inertia, is examined in this paper, based on a continuum cylindrical shell model. The disperse curves are obtained by solving an eigenvalue problem. The characteristics of wave propagation in liposomes are described using numerical ex les. The results show that wave propagation in liposomes has a threshold critical frequency beyond which the wave speed drops dramatically and also a cut-off critical frequency below which the corresponding wave mode does not appear. The torsional wave speed is obtained for the symmetrical circumferential mode n = 0. The cut-off or threshold critical frequency decreases with the increase of liposomal radius, but the effect of radius on wave speed is not significant in the frequency region higher than the critical frequency. On the other hand, the wave number n leads to an increase in the critical frequency. For the first and second wave modes, the wave speed is insensitive to the wave number when the frequency is greater than the critical frequency. For the third wave mode in the low frequency region, the wave number leads to an increase in the wave speed. The rotary inertia has little influence on those wave modes which contain cut-off frequencies. For other wave modes, the rotary inertia results in a decrease in the wave speed in the high frequency region. This investigation may provide a useful guide in the applications of liposomes in ultrasound-based drug delivery and release.
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.535-536.497
Abstract: 5083 aluminum alloy was investigated with respect to its uniaxial dynamic compressive properties over a range of strain rates using the split Hopkinson pressure bar (SHPB). The dynamic stress-strain curves of this alloy were obtained for strain rates from 1000 s-1 to 6000 s-1. Effects of strain rate, the s les size and anti-impact capability were analyzed. The experimental results show that under impaction loading, 5083 aluminum alloy has a remarkable strengthening response to strain rate and size in particular, the responded stress increases with increasing strain rate, which implies that this alloy has high strength and high anti-impact capability.
Publisher: SAGE Publications
Date: 02-04-2022
DOI: 10.1177/13694332221086701
Abstract: Hierarchical and graded honeycomb structures are extensively applied in many fields due to their excellent compression properties and energy absorption capacity. In the present study, the segmented graded hierarchical honeycomb structures with triangle substructures (GHT) are constructed to numerically investigate the in-plane crushing performance by the nonlinear finite element analysis code ABAQUS/Explicit. GHT exhibits the best energy absorption capacity compared to graded regular hexagonal honeycomb structures (GRH), graded hierarchical structures with Kagome substructures (GHK) and graded hierarchical structures with hexagonal substructures (GHH). The comprehensive effect of inertia and yield strength at each layer is illustrated by investigating the deformation modes under different loading speeds. The plateau stress is discussed in two ways: the overall average plateau stress corresponding to the whole structure and the segmental plateau stress corresponding to the specific layer. The relationship between overall average plateau stress, relative density and loading speed for the graded structure is established based on one-dimensional shock wave theory and compared with the uniform structure. The segmental properties of plateau stress at both impact and fixed ends are investigated in detail by combining theoretical analysis and deformation characteristics, and the results show good consistency with the simulation results at low, medium, and high loading speed conditions. Finally, the concept of cyclic graded structure is introduced, which can further optimize the energy absorption capacity and provide guidance for the design of new multifunctional structures.
Publisher: SAGE Publications
Date: 04-09-2017
Abstract: Monolithic and sandwich structures have been widely used as energy absorption structures in military and civil engineering. This article reviews theoretical analyses of monolithic beams and plates subjected to static loading, impulsive loading and impact by a mass systematically. Experimental data collected from the literatures are compared with these theoretical results. In addition, the critical impulses for the failure of the monolithic structures are also reviewed. Furthermore, sandwich structures under quasi-static, low-velocity impact, high-velocity impact and blast loading, as well as their failure modes, are also summarized. The research methodology involves experimental investigations, theoretical analyses and numerical simulations.
Publisher: Elsevier BV
Date: 04-1999
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 05-2016
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 04-2020
Publisher: Trans Tech Publications, Ltd.
Date: 05-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.261-263.761
Abstract: One potential application of aluminium foam sandwich panels in civil engineering is the cladding system which is employed to protect other structures again impact and blast loadings. Finite element (FE) simulation of these sandwich panels subjected to impact loading was conducted by using a commercial software package, LS-DYNA (version 971). The FE model was verified by experimental results conducted previously. Good agreement was achieved between the FE and experimental results. Parametric study was conducted to investigate the effects of skin thickness, core thickness and boundary conditions on the deformation modes and energy absorption of sandwich panels with aluminum foam core.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Oxford University Press (OUP)
Date: 13-10-2011
Publisher: Springer New York
Date: 13-09-2012
Publisher: Elsevier BV
Date: 11-2017
Publisher: Informa UK Limited
Date: 15-12-2010
Publisher: Elsevier BV
Date: 11-2001
Publisher: SAGE Publications
Date: 09-2002
DOI: 10.1177/095440620221600901
Abstract: Based on the classical Alexander solution for the axial collapse of bare metal tubes, a theoretical model is presented to predict the mean crushing force of arbitrarily fibre-reinforced metal tubes with a ring collapse mode. The derived mean crushing force and length of the local folding wave are more reasonable and are in better agreement with the experiments than previously obtained. The effect of wrapping direction of the reinforcing fibres is studied. This model for predicting the static mean crushing force can be extended for the dynamic mean crushing force of fibre-reinforced metal tubes under axial impact load.
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.535-536.481
Abstract: An analytic model is developed to obtain the dynamic response of beams with initial velocities of the upper beam which is cl ed at both ends and fully supported by metal foam, as a representative arrangement for protective structures. In large deflection, plastic bending and stretching in deforming regions are considered and the membrane factor method is introduced in the model to take into account the effect of axial force in the yielding. The relationships between the final displacement of the center in the beam and the dimensionless parameters are obtained. This model can predict the dynamic effects of different initial velocities and beams with different lengths, thickness and yield strength of cores.
Publisher: Elsevier BV
Date: 07-2002
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 1995
Publisher: Informa UK Limited
Date: 11-09-2008
Publisher: SAGE Publications
Date: 10-2008
DOI: 10.1260/136943308786412005
Abstract: This paper first presents an experimental investigation into the response of square sandwich panels with an aluminium foam core under blast loading, followed by a corresponding FE simulation using LS-DYNA. In the simulation, the loading process of explosive and response of the sandwich panels have been investigated. The blast loading process includes both the explosion procedure of the charge and interaction with the panel. The simulation result shows that the deformation/failure patterns observed in the tests are well captured by the numerical model, and quantitatively a reasonable agreement has been obtained between the simulation and experiment. Finally, a parametric study has been carried out to investigate the energy absorption performance of sandwich panels.
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 11-2005
DOI: 10.1016/J.JACI.2012.07.053
Abstract: Allergic rhinitis (AR) and asthma represent global health problems for all age groups. Asthma and rhinitis frequently coexist in the same subjects. Allergic Rhinitis and its Impact on Asthma (ARIA) was initiated during a World Health Organization workshop in 1999 (published in 2001). ARIA has reclassified AR as mild/moderate-severe and intermittent ersistent. This classification closely reflects patients' needs and underlines the close relationship between rhinitis and asthma. Patients, clinicians, and other health care professionals are confronted with various treatment choices for the management of AR. This contributes to considerable variation in clinical practice, and worldwide, patients, clinicians, and other health care professionals are faced with uncertainty about the relative merits and downsides of the various treatment options. In its 2010 Revision, ARIA developed clinical practice guidelines for the management of AR and asthma comorbidities based on the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system. ARIA is disseminated and implemented in more than 50 countries of the world. Ten years after the publication of the ARIA World Health Organization workshop report, it is important to make a summary of its achievements and identify the still unmet clinical, research, and implementation needs to strengthen the 2011 European Union Priority on allergy and asthma in children.
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.JMBBM.2019.103603
Abstract: The paper presents for the first time the material properties and energy absorption capacity of durian shells with an attempt to use as an alternative sustainable material and mimic their structural characteristics to design a bio-inspired structure for protective packaging applications. A series of quasi-static compression tests were carried out to determine Young's modulus and bioyield stress of the durian shells as well as their energy absorption capacity. The mesocarp layers and thorns are interesting parts for investigating their energy absorption characteristics because they play an important role in protecting the flesh of durians during their drop impact onto the ground. The mesocarp layers of the shell were subjected to axial and lateral compression while the thorn specimens were compressed under axial loading with an increasing number of thorns. The results showed that the densification strain, plateau stress and specific energy absorption of the mesocarp layer under lateral loading is higher than that under axial loading. Furthermore, the compression tests on the thorns demonstrated that an increase in the number of thorns helped to absorb more energy and the specific energy absorption of the thorns was nearly two times higher than that of the mesocarp layer under the axial loading. In addition, the cyclic loading of the thorns showed that the extent of reversibility of deformation in the thorns decreases from 32% at the first cycle to around 10% at the 9th-cycle. Finally, the microstructure of the thorn and mesocarp layer was investigated to explain the experimental observation. The results indicated that the spherical shape associated with the thorns and mesocarp materials displayed an excellent energy absorption efficiency that can be mimicked to design an effective bio-inspired absorber for packing applications.
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 11-2012
Publisher: Elsevier BV
Date: 11-2022
Publisher: American Society of Mechanical Engineers
Date: 14-11-2014
Abstract: Aluminium honeycombs is a lightweight cellular material and a good energy absorber. In different engineering applications, it is usually used as structural components. Comprehensive study has been conducted to analyse the compressive behaviour of aluminium honeycombs. However, research related to mechanical response of aluminium honeycombs material subjected to different type of loadings, such as indentation, is still limited. In this paper, experimental and numerical studies were conducted to investigate the deformation mechanism and energy dissipation of a HEXCELL® aluminium honeycomb subjected to dynamic indentation. A high speed INSTRON machine was used to conduct dynamic tests at velocities of 0.5 m/s and 5 m/s. Numerical analysis was conducted using ANSYS LS-DYNA at velocities of 5 m/s, 15 m/s and 25 m/s. The simulation results were in good agreement with the experimental results in terms of stress-strain curve profile and deformation mode. In the experiment, it was found that with the increase of velocity (strain rate) the average plateau stress of indentation also increases which was validated in the numerical analysis. The deformation of aluminium honeycombs under indentation showed that the compression of hexagonal honeycomb cells under the indenter and also tearing of honeycomb cell walls along the four edges of the indenter. The dissipation of energy in compression and tearing was calculated and discussed. The effect of loading velocity on the plateau stress and energy absorption was also analyzed.
Publisher: Elsevier BV
Date: 07-2020
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2013
DOI: 10.1142/S1758825113500087
Abstract: In the present paper, the mechanical behavior of large deformation of a regular equilateral triangular tube under quasi-static axial crushing is reported, which is a polygon with an acute angle and odd number of sides. Based on the results from nonlinear finite element analysis (FEA), a new type of inextensional basic plastic collapse folding element is proposed to describe the plastic progressive collapse. The progressive folding around the stationary horizontal hinges and inclined traveling hinges are involved to develop the new basic folding element. Two types of inextensible deformation modes are discovered, i.e., diamond mode and rotational symmetrical mode. The average crushing load for each mode is predicted from the super-folding element theory, which was proposed from the previous investigation on the axial crushing of square columns. A rigid-plastic material model and a kinematically admissible model are involved in this theory. The results are further validated against experiments. The approximate quasi-static theoretical predictions for the mean crushing loads of triangular tubes provide reasonable agreement with the corresponding experimental results.
Publisher: Informa UK Limited
Date: 2003
Publisher: Trans Tech Publications Ltd.
Date: 15-06-2006
Publisher: SAGE Publications
Date: 07-2003
DOI: 10.1243/095440603767764381
Abstract: In this paper, a polynomial stress function is utilized to satisfy both the governing differential equation for an anisotropic plane stress problem and the corresponding boundary conditions for plastic deformation. A theoretical solution for the thermal elastic-plastic problem of composite structure is obtained by means of the Tsai-Hill strength theory of anisotropic material. The composite structure is composed of a steel fibre-reinforced aluminium metal-matrix with a linear hardening material property. On the other hand, an elastic-plastic finite element analysis for the same problem is also carried out by using ABAQUS. The theoretical solution is in good agreement with the results from the finite element analysis. Finally, some ex les are given and the corresponding results are discussed.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2019
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.794.202
Abstract: Carbon fibre composite tubes have high strength to weight ratios and outstanding performance under axial crushing. In this paper, square CFRP tubes and aluminium sheet-wrapped CFRP tubes were impacted by a drop mass to investigate the effect of loading velocity on the energy absorption of CFRP/aluminium tubes. A comparison of the quasi-static and dynamic crushing behaviours of tubes was made in terms of deformation mode, peak crushing force, mean crushing force, energy absorption and specific energy absorption. The influence of the number of aluminium layers that wrapped square CFRP tubes on the crushing performance of tubes under axial impact was also examined. Experimental results manifested similar deformation modes of tubes in both quasi-static and dynamic tests. The dynamic peak crushing force was higher than the quasi-static counterpart, while mean crushing force, energy absorption and specific energy absorption were lower in dynamic tests than those in quasi-static tests. The mean crushing force and energy absorption decreased with the crushing velocity and increased with the number of aluminium layers. The impact stroke (when the force starts to drop) decreased with the number of aluminium layers.
Publisher: Trans Tech Publications, Ltd.
Date: 12-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.725.143
Abstract: This work studies the large deformation behaviors of a re-entrant honeycomb subjected to the quasi-static tensile loading by employing the finite element (FE) package ABAQUS 6.11-2. The size effect of FE models is firstly investigated. Then, the deformation mechanism and stress-strain curve of a re-entrant honeycomb are discussed. Finally, the plastic Poisson’s ratio is calculated from the true strain and presented.
Publisher: Springer International Publishing
Date: 2015
Publisher: ASME International
Date: 07-03-2016
DOI: 10.1115/1.4031953
Abstract: Rigid origami inspires new design technology in deployable structures with large deployable ratio due to the property of flat foldability. In this paper, we present a general kinematic model of rigid origami pattern and obtain a family of deployable prismatic structures. Basically, a four-crease vertex rigid origami pattern can be presented as a spherical 4R linkage, and the multivertex patterns are the assemblies of spherical linkages. Thus, this prismatic origami structure is modeled as a closed loop of spherical 4R linkages, which includes all the possible prismatic deployable structures consisting of quadrilateral facets and four-crease vertices. By solving the compatibility of the kinematic model, a new group of 2n-sided deployable prismatic structures with plane symmetric intersections is derived with multilayer, straight and curvy variations. The general design method for the 2n-sided multilayer deployable prismatic structures is proposed. All the deployable structures constructed with this method have single degree-of-freedom (DOF), can be deployed and folded without stretching or twisting the facets, and have the compactly flat-folded configuration, which makes it to have great potential in engineering applications.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Trans Tech Publications Ltd.
Date: 15-06-2006
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.535-536.501
Abstract: Similar blast loading characteristics can be obtained using impact of aluminium foam projectiles, which enables blast tests to be mimicked in a laboratory scale and in a safer environment. The purpose of this study is to determine the back-face deflection history of aluminium sandwich panels experimentally by aids of a laser displacement meter when panels are subjected to the impact of metal foam projectiles. This information was usually determined using finite element analysis (FEA) due to the difficulty in the experiment. The projectiles are cylindrical ALPORAS aluminium foam with diameter of 37 mm, length of 50 mm and nominal relative density of 10%. The sandwich panels consist of two 1 mm aluminium face-sheets and an aluminium honeycomb as the core. There are five different core configurations with a brand name of HEXCEL. The projectiles are fired towards the centre of the sandwich panels at different velocities using a gas gun. During the tests, a laser optical displacement measuring device is used to record the history of the back-face deflection experimentally. The deflection of the back-face is found to reach the maximum before coming to rest at a smaller value. The final back-face deflections of the sandwich panels show exponential relationship with the projectile impulse. The final deflections are compared with the deflection of monolithic plates with equal mass. The sandwich panels deflect less than the monolithic plate with an equal mass up to a critical value but continue to increase significantly afterwards. Care should be taken when using sandwich panels as protective structures against foam projectiles as beyond this point, the monolithic plates outperform the sandwich panels in absorbing the impact load.
Publisher: Elsevier BV
Date: 08-1994
Publisher: Elsevier BV
Date: 12-2021
Publisher: Springer Science and Business Media LLC
Date: 12-01-2021
DOI: 10.1038/S41598-020-80661-Y
Abstract: The contribution of low-frequency variants to the genetic architecture of normal-range facial traits is unknown. We studied the influence of low-frequency coding variants (MAF 1%) in 8091 genes on multi-dimensional facial shape phenotypes in a European cohort of 2329 healthy in iduals. Using three-dimensional images, we partitioned the full face into 31 hierarchically arranged segments to model facial morphology at multiple levels, and generated multi-dimensional phenotypes representing the shape variation within each segment. We used MultiSKAT, a multivariate kernel regression approach to scan the exome for face-associated low-frequency variants in a gene-based manner. After accounting for multiple tests, seven genes ( AR , CARS2 , FTSJ1 , HFE , LTB4R , TELO2 , NECTIN1 ) were significantly associated with shape variation of the cheek, chin, nose and mouth areas. These genes displayed a wide range of phenotypic effects, with some impacting the full face and others affecting localized regions. The missense variant rs142863092 in NECTIN1 had a significant effect on chin morphology and was predicted bioinformatically to have a deleterious effect on protein function. Notably, NECTIN1 is an established craniofacial gene that underlies a human syndrome that includes a mandibular phenotype. We further showed that nectin1a mutations can affect zebrafish craniofacial development, with the size and shape of the mandibular cartilage altered in mutant animals. Findings from this study expanded our understanding of the genetic basis of normal-range facial shape by highlighting the role of low-frequency coding variants in several novel genes.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Elsevier BV
Date: 10-1995
Publisher: Elsevier BV
Date: 06-2001
Publisher: Elsevier BV
Date: 08-2017
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 05-2008
Publisher: EDP Sciences
Date: 2018
DOI: 10.1051/EPJCONF/201818302027
Abstract: The Split Hopkinson Pressure Bar (SHPB) test, while widely utilised for high strain rate tests, has yet to be standardised. As an exploratory step towards developing a standard test method or protocol, a Round Robin test series has been conducted between four institutions: (i) Swinburne University of Technology, Australia (ii) University of São Paulo, Brazil, (iii) University of Cape Town, South African and (iv) Nanyang Technological University, Singapore. Each institution prepared specimens from a metallic material, and provided batches of specimens from their chosen material to the other institutions. The materials utilised in this round of testing were commercially pure copper and aluminium, magnesium alloy and stainless steel (316 grade). The intent of the first exercise is to establish the consistency of SHPB test results on nominally identical specimens at comparable elevated strain rates, conducted by different laboratories following notionally similar test procedures with some freedom in data processing. This paper presents and compares the results of the first batch of tests for copper, identifying variations between results from different laboratories. The variation between different laboratories’ results for copper is suffciently small that there is confidence in the potential to develop a draft standard in future.
Publisher: Elsevier BV
Date: 10-2022
Publisher: World Scientific Pub Co Pte Ltd
Date: 06-2012
DOI: 10.1142/S1758825112500172
Abstract: This paper examines the dynamic stability of an elastic beam on the elastic foundation, in which the stress wave effect is taken into account. Based on Euler–Bernoulli beam theory, the dynamic response of the elastic beam on the elastic foundation to a small transverse perturbation is analyzed. By considering the stress wave propagation in the beam and the constraint of the elastic foundation, the critical bifurcation condition of elastic beam is derived, and the critical axial load of the elastic beam is predicted. Furthermore, the effects of the elastic foundation and the beam length on buckling condition are discussed by using numeric ex les. Finally, an approximate solution of critical axial load for elastic beam on the elastic foundation is provided, which may be used to investigate elastic beam buckling problem.
Publisher: Elsevier BV
Date: 05-2002
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 11-2018
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.950
Abstract: The compressive behavior of two closed cell aluminum foams (Alporas and Cymat) were investigated under various strain rates from 10-3 to 102 s-1 using compressive tests conducted on MTS and Instron test machines. High speed camera videos show that localized deformation occurs in Alporas foam specimens uniformly, but not in Cymat foams. The stress-strain curves for Alporas foams are smooth and regular, while they oscillate dramatically for Cymat foams. Alporas foams exhibit strain rate sensitivity, i.e. with an increase in strain rate, the normalized plateau stress and energy absorption capacity increase. The plateau stress for Cymat foams was more sensitive than Alporas to strain rate, but the energy absorption less so, at least at a nominal relative density of 10%.
Publisher: Elsevier BV
Date: 08-2005
Publisher: AIP Publishing
Date: 23-01-2013
DOI: 10.1063/1.4775788
Abstract: A hybrid method is proposed to study atomic diffusion behavior in Cu-Al explosive welding process. The method combines molecular dynamics simulation and classical diffusion theory. Cu-Al explosive welding and scanning electron microscope experiments are done to verify the method. Using the method, we find that the atomic diffusion mostly takes place in the unloading stage of the welding process. The diffusion coefficients are collision velocity-dependent, with higher velocities generating larger coefficients. When there is no transverse velocity, the diffusion coefficient is directly proportional to the longitudinal velocity. With the longitudinal velocity fixed, the diffusion coefficient is proportional to the square of the transverse velocity. The thickness of the diffusion layer is calculated from the simulation result, and it is in good agreement with the experiment result.
Publisher: Elsevier BV
Date: 08-2005
Publisher: Woodhead Publishing Limited
Date: 2003
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 02-2020
Publisher: American Society of Mechanical Engineers
Date: 04-08-2013
Abstract: Because of the internal mobility, rigid origami structures have great potential in engineering applications. In this research, a kinematic model of the rigid origami pattern is proposed based on the assembly of spherical 4R linkages. To ensure the rigid origami pattern with mobility one, the kinematic and geometric compatibility conditions of the kinematic model are derived. Four types of flat rigid origami patterns are obtained, including three existing types as well as a novel one called the supplementary type. To testify and display the mobile processes of the patterns, their simulation models are built accordingly.
Publisher: Elsevier BV
Date: 06-2002
Publisher: Trans Tech Publications, Ltd.
Date: 12-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.725.162
Abstract: Rock movement caused by external explosion loading can damage the nearby tunnel or cavern.To avoid damage, energy absorbing bolts with high load-displacement and large energy absorptioncapacities are required. The deformation and friction of the bolt absorb energy during the rock movementand preventing the structure from damage. To maximize the energy absorption capacity in the limitedspace inside the borehole, we developed a new bolt that utilizes the friction and plastic deformation ofthe sleeve. To develop the new bolt, FE simulation in Abaqus was used to improve designs beforefabrication. Two prototypes of the new design was fabricated and tested by static pull test. The resultsshowed the bolts yielded in the desired way. The experimental results prove the new bolt is capable ofabsorbing large amount of energy and accommodating large displacement.
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 12-2014
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2016
DOI: 10.1142/S1758825116500253
Abstract: In this study, two kinds of dynamic compression tests were conducted using direct-impact Hopkinson pressure bar (DHPB) facilities, i.e., the bullet with foam specimen was shot on the transmission bar, or the foam specimen was mounted at the end surface of the transmission bar and was hit by a bullet directly. Stress enhancement and localized deformation, as two mainly dynamic properties of metal foam, were observed in the experiments. Then, dynamic locking strain is proposed in order to better describe the feature of foam’s localized deformation field during the impact process. A rigid- perfectly-plastic-dynamic-locking strain model (R-P-P-D-L model) is developed to study the dynamic properties of the foams. The parameters included in this model are determined by 3D numerical Voronoi model and experiments. Comparing the predictions from R-P-P-D-L model with numerical results and experimental results, it is found that the R-P-P-D-L model can capture the main deformation mechanisms of the foam in dynamic compression, and provide a more precise prediction than R-P-P-L model. Furthermore, the stress enhancement of foam with the relative density and the impact velocity are discussed using the R-P-P-D-L model.
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 11-2022
Publisher: Trans Tech Publications, Ltd.
Date: 12-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.725.82
Abstract: In this study, hollow square carbon fibre reinforced plastic (CFRP) tubes and aluminium sheet wrapped CFRP tubes have been axially crushed at a quasi-static loading velocity of 0.05 mm/s. A specially designed and manufactured platen with four cutting blades was used to cut and crush these two tubular structures. The four cutting blades had height of 5 mm and width of 3 mm with round tip to reduce the initial peak force and achieve a stable crushing deformation mode. Notches at one end of each tube were utilized to control the location of initial failure. The crashworthiness characteristics of hollow CFRP tubes and aluminium sheet wrapped CFRP tubes with notches that crushed by the platen with cutting blades were compared with those of tubes that crushed by a flat platen. Experimental results showed that using the platen with blades to crush the specimens with notches exhibited more stable deformation mode than the specimens without notches. Mean crushing force, energy absorption and specific energy absorption (SEA) increased when CFRP was wrapped with aluminium sheet and crushed by the platen with blades. The increase of average value of mean crushing force, energy absorption and specific energy absorption of aluminium sheet wrapped CFRP tube and crushed by the platen with blades are 16.5%, 17.3% and 5% respectively more than those for hollow tubes that crushed by a flat platen.
Publisher: IEEE
Date: 06-2019
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 02-2015
Publisher: SAGE Publications
Date: 03-2009
Abstract: A new testing method using a mini split Hopkinson tensile bar was employed in the impact tests of Lincoln wool fibers. Stress-strain curves of Lincoln wool fibers subjected to impact loadings at strain rates in the order of 10 2 s —1 were obtained, which fill the gap in the impact data for Lincoln wool fibers. For comparison, quasi-static tests were also carried out with a single Lincoln wool fiber using a Micro-Tester. Stress level was observed to increase with increasing strain rates.
Location: Saudi Arabia
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Guoxing Lu.