ORCID Profile
0000-0002-6446-0124
Current Organisation
UNSW Sydney
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Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 08-2008
Publisher: SAGE Publications
Date: 23-09-2019
Abstract: Automated fibre placement-based manufacturing technology is increasingly being used in several engineering applications. Manufacture of carbon fibre-reinforced plastic’s small/large structures have been made possible due to its remarkable capabilities like productivity and accuracy. Nevertheless, making high-quality composite laminate using automated fibre placement relies on the proper selection of critical processing variables to avoid internal flaws during the fibre placement process. Consequently, a reliable non-destructive inspection technique is required for quality assurance and structural integrity of fabricated laminates. Neutron radiography/tomography offers unique imaging capabilities over a wide range of applications including fibre-reinforced polymer composites. The application of this technique towards tomographic reconstruction of automated fibre placement-made thermoplastic composites is presented in this paper. It is shown that the porosity analysis using neutron imaging technique provides reliable information. Additionally, using such technique valuable data regarding the size and the location of the voids in the laminate can be acquired and informed. This will assist the composite structural analysts and designers to select the appropriate processing parameters towards a defect free automated fibre placement part manufacture.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 10-2015
Publisher: SAGE Publications
Date: 15-03-2023
DOI: 10.1177/00219983231160866
Abstract: Embedded optical fibre sensors (OFSs) offer the potential to monitor the internal strains at various stages during the manufacturing and service life of fibre-reinforced polymer (FRP) composite structures. Various aspects associated with the embedment of OFSs, such as integration, material compatibility, and sensing performance of the embedded sensor needs to be investigated to develop reliable OFSs based internal sensing platform for composite structures. In this study, Polyimide (PI) and Polyether ether ketone (PEEK) coated optical fibres (OF) were embedded into glass fibre-reinforced polymer (GFRP) composites to evaluate four important aspects associated with the embedment of OFs, which include i). Structural integrity of the OFs against chemical reactions from vinyl ester resin and its additives through immersion testing, ii). Methods of integrating the OFs into layered glass fibres for the vacuum resin infusion manufacturing process, iii). Sensing performance of the embedded OFs during manufacturing and structural testing (tensile and compressive), and iv). Internal structural integrity of the embedded OFs and the host composite structure using X-Ray micro-computerised tomography technique (μ-CT). The results from the immersion testing and manufacturing process monitoring showed that both PEEK and PI coated OFs can resist the chemical and mechanical stresses caused by resin polymerisation during curing process. The subsequent mechanical testing showed a similar sensing performance by the PI and PEEK coated OFs. Under tensile loads, the OFs monitored the tensile strain distribution up to 7,000 με and compressive strain distribution up to −1,200 με under flexural loading without compromising their optical performance. Finally, the μ-CT scanning results had shown a minimal structural deterioration of the embedded OFs and host composite structure. The outcomes from this detailed experimental investigation on the embedment of OFS in GFRP structures provided useful information towards the integration and performance of optical sensors in composite structures.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-03-2015
Publisher: Elsevier BV
Date: 10-2014
Publisher: ASME International
Date: 12-2011
DOI: 10.1115/1.4005229
Abstract: The Thompson coupling is a relatively recent design of constant-velocity coupling, that is, principally based on the double Cardan mechanism. An extra mechanism comprising a spherical pantograph serves to align the intermediate shaft of this coupling and so maintains the constant velocity of the double Cardan mechanism, in a modular fashion. This technical note serves to introduce basic closed form expressions for the coupling’s geometry—which may then be used to derive linkage accelerations and dynamic forces. The expressions are derived using standard identities in spherical geometry. The resulting dynamic model then informs a basic conceptual design optimization, which object is intended to reduce induced driveline vibrations, when the coupling is articulated at nonzero angles of torque transmission.
Publisher: IEEE
Date: 04-2016
Publisher: Elsevier BV
Date: 09-2011
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 10-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY01286F
Abstract: The surface of commercial graphene oxide was modified with polymers using Passerini reaction, which enhances the compatibility between nanoparticles and 3D printing resin.
Publisher: Elsevier BV
Date: 09-2011
Publisher: Informa UK Limited
Date: 12-2013
Publisher: SAGE Publications
Date: 04-2005
Abstract: Progressive failure analysis of laminated unstiffened and stiffened composite panels has been carried out in the present investigation. The laminated panels under transverse static loadings in the linear elastic range have been investigated using the finite element method. In the finite element analysis of stiffened panels, eight-noded isoparametric quadratic elements in association with the three-noded curved beam elements have been considered and the first-order shear deformation theory is utilized. An iterative method has been adopted using the various failure theories to predict the first-ply failure load. After the first-ply failure, the stiffness of the failed lamina has been totally discarded from the laminate and the remaining laminae were considered for further analysis. The progressive failure analysis using the Tsai-Wu failure criterion has been implemented into a general-purpose finite element code to predict the failure loading from the initial to the final stage.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 10-2020
Publisher: SPIE
Date: 09-08-2013
DOI: 10.1117/12.2028607
Publisher: SPIE
Date: 09-08-2013
DOI: 10.1117/12.2028606
Publisher: Elsevier BV
Date: 12-2009
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2018
Publisher: Springer Science and Business Media LLC
Date: 07-03-2019
DOI: 10.1038/S41598-019-40524-7
Abstract: Interfacial bonding between fibre and matrix is most critical to obtain enhanced mechanical properties of the resulting composites. Here we present a new surface tailoring method of selective wet etching and organosilicon monomers (3-(Trimethoxysilyl) propyl methacrylate, TMSPMA) deposition process on the short S-Glass fibre as a reinforcing material, resulting in increased mechanical retention and strong chemical bonding between glass fibres and polymer resin (a mixture of triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) monomers). The effect of surface modification on fibre matrix interfacial strength was investigated through microdroplet tests. An S-Glass fibre treated with piranha solution (a mixture of H 2 O 2 and H 2 SO 4 ) for 24 hours followed by TMSPMA surface silanization shows highest increase up to 39.6% in interfacial shear strength (IFSS), and critical fibre length could be reduced from 916.0 µm to 432.5 µm. We find the optimal surface treatment condition in that the flexural strength of dental composites reinforced by the S-Glass fibres enhanced up to 22.3% compared to the composites without fibre surface treatments. The significant elevation in strength is attributed to changes in the surface roughness of glass fibres at atomic scale, specifically by providing the multiplied spots of the chemical bridge and nano-mechanical interlocking. The findings offer a new strategy for advanced tailoring of short S-Glass fibres to maximise the mechanical properties of biomedical and dental composites.
Publisher: SAGE Publications
Date: 09-07-2013
Abstract: An improved third-order shear deformation theory is employed to investigate free and forced vibration responses of functionally graded plates. A power law distribution is used to describe the variation of material compositions across the plate thickness. The governing equations for vibration analysis obtained using an energy approach are then solved using the Ritz method. Two types of solutions, temperature independent and dependent material properties, are considered. Many effects of the volume fraction index, temperature, material pairs, thickness, plate aspect ratio, etc., which have significant impact on dynamic behaviour of the plates, are considered in the numerical illustrations of free and forced vibration results. At high temperatures, it is observed that the maximum deflections of the functionally graded plates subjected to the dynamic loading increase with the increase of frequency ratio and temperature.
Publisher: SAGE Publications
Date: 28-04-2019
Abstract: Interest in natural fiber–reinforced composites (NFRCs) is increasing rapidly thanks to their numerous advantages such as low cost, biodegradability, eco-friendly nature, relatively good mechanical properties, and a growing emphasis on the environmental and sustainability aspects of engineering materials. However, large-scale use of NFRCs is still considered as challenging due to the difficulties in manufacturing, limited knowledge of its machinability and appropriate parameter settings, and being prone to machining-induced defects. This article presents a comprehensive review on various aspects of NFRCs, with a focus on the manufacturing and machinability. It covers some recent works related to NFRCs, including the manufacturing processes and parameters, characterization of mechanical properties, applications, and machinability and machining process monitoring, many for the first time. The main challenges associated with machining of NFRCs and the induced damages are outlined, with special attention paid to the effect of physical properties of the fibers and manufacturing process on the machinability, along with the essential machining parameters that affect the quality of the machined surface. The research perspectives and the current application status are also discussed. The article is intended to help readers attain a fundamental understanding of key technologies and the state of the arts in this research area.
Publisher: Springer Science and Business Media LLC
Date: 08-2011
Publisher: Elsevier BV
Date: 2020
Publisher: IOP Publishing
Date: 03-12-2021
Abstract: Fibre reinforced composites materials offer a pathway to produce passive shape adaptive smart marine propellers, which have improved performance characteristics over traditional metallic alloys. Automated fibre placement (AFP) technology can provide a leap forward in cyber-physical automated manufacturing, which is essential for the implementation and operation of smart factories in the marine propeller industry towards Industry 4.0 readiness. In this paper, a comprehensive structural health monitoring routine was performed on an AFP full-scale composite hydrofoil to gain confidence in its dynamic and structural performances through a number of active and passive sensors. The hydrofoil was subjected to constant litude flexural fatigue loading in a purpose-built test rig for 10 5 cycles. The hydrofoil was embedded with distributed optical fibre sensors, traditional electrical strain gauges and linear variable displacement transducers. Both microelectromechanical system and piezoelectric accelerometers were used to conduct experimental modal analyses to observe changes in the modal response of the hydrofoil at regular intervals throughout the fatigue program. The hydrofoils modal response, as well as the stiffness measured using both displacements and strains, remained unchanged over the fatigue loading regime demonstrating the structural integrity of the hydrofoil. The optical fibre sensors endured the fatigue test cycles showing their robustness under fatigue loads. Furthermore, the sensing systems demonstrated the potential of being utilised as a useful maintenance tool combining their adaptability with automated manufacturing during manufacturing through integration within the hydrofoil, a structural test framework for performance measurement, data acquisition and analytics for visualisation, and the prospect of decision making for maintenance requirement during any onset in structural performance.
Publisher: Elsevier BV
Date: 04-2012
Publisher: Elsevier BV
Date: 03-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2020
Publisher: Elsevier BV
Date: 11-2020
Publisher: IEEE
Date: 04-2016
Publisher: MDPI AG
Date: 15-03-2019
DOI: 10.3390/S19061310
Abstract: Precision sensing in the characterization of complex additive manufacturing processes such as the Automated Fibre Placement (AFP) technique is important since the process involves a significant level of uncertainty in terms of quality and integrity of the manufactured product. These uncertainties can be monitored by embedding optical fibre Bragg grating (FBGs) sensors which provide accurate and simultaneous measurement of strain and temperature during the AFP process. The embedded sensors have been shown to remain resilient in continuous health monitoring after manufacturing. The thermal history obtained from the FBG sensors demonstrates a reduction of temperature on the bottom ply by up to 25% when the plies are laid one above the other. A numerical tool is developed to identify the physical parameters which may be responsible for the rise/fall of the temperature during ply layup. The numerical findings agree well with the sensor data and is extended to capture a breadth of parametric studies through the layup simulation. The model provides a comprehensive insight to the characteristics of the laid and the laying ply from a thermo-mechanics perspective.
Publisher: Wiley
Date: 02-11-2020
DOI: 10.1002/APP.50208
Publisher: Elsevier BV
Date: 09-2003
Publisher: Elsevier BV
Date: 12-2021
Publisher: Wiley
Date: 02-07-2010
Publisher: Informa UK Limited
Date: 03-04-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-08-2019
Publisher: Elsevier BV
Date: 12-2020
Publisher: American Chemical Society (ACS)
Date: 05-02-2019
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.DENTAL.2016.06.015
Abstract: The characterization of the physical properties of dental resin composites is fraught with difficulties relating to significant intra and inter test parameter variabilities and is relatively time consuming and expensive. The main aim of this study was to evaluate whether optical fiber Bragg grating (FBG) sensing system may become a viable tool to study dental material characteristics. Of particular focus was the potential for the system to demonstrate a multi parameter all-in-one feature. A miniature FBG was embedded in six different dental resin composites and employed as a sensor to evaluate linear polymerization shrinkage, thermal expansion and water sorption. Six commercially available dental composites with different filler types and volume are evaluated. The tests are repeated with three sets of s les. The curing characteristics and residual strain gradient exhibited by the cured dental composites were also observed and commented. Among the studied s les, SDR shows lowest polymerization shrinkage, while Beautifil FO3 shows the highest. The results also show clear distinction between particle filler type and fiber reinforcement based composites in their polymerization shrinkage properties. The agreement of the results with existing literatures show that FBG based system provides accurate results. Polymerization shrinkage rate of the s les are also obtained. Thermal expansion of the composites are measured using the FBG sensing method for the first time and is correlated with resin type, volume, filler type and glass transition temperature. The water sorption characteristics of the dental composite are also successfully measured using the FBG sensing method. The high level of repeatability and the low standard deviations shown in the results indicate good reliability with the use of FBG sensors. This study demonstrates how optical fiber technology can provide simple and reliable methods of measuring the critical physical properties of dental composites. In addition due to the embedding and preservation of the sensor within the s les multiple parameters can be tested for with the same s le. These features are expected to greatly assist material science researchers in dentistry as well as other biomedical fields. Of some interest the phenomenon of stress relaxation of dental composite at higher temperature was observed.
Publisher: Elsevier BV
Date: 06-2001
Publisher: Elsevier BV
Date: 2021
Publisher: IEEE
Date: 07-2019
Publisher: Elsevier BV
Date: 09-2017
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 11-2023
Publisher: Elsevier BV
Date: 03-2023
Publisher: Wiley
Date: 04-07-2007
Publisher: Informa UK Limited
Date: 28-05-2014
DOI: 10.1080/10255842.2013.873420
Abstract: This paper discusses various issues relating to the mechanical properties of a braided non-vascular stent made of a Ni-Ti alloy. The design of the stent is a major factor which determines its reliability after implantation into a stenosed non-vascular cavity. This paper presents the effect of the main structural parameters on the mechanical properties of braided stents. A parametric analysis of a commercial stent model is developed using the commercial finite element code ANSYS. As a consequence of the analytical results that the pitch of wire has a greater effect than other structural parameters, a new design of a variable pitch stent is presented to improve mechanical properties of these braided stents. The effect of structural parameters on mechanical properties is compared for both stent models: constant and variable pitches. When the pitches of the left and right quarters of the stent are 50% larger and 100% larger than that of the central portion, respectively, the radial stiffness in the central portion increases by 10% and 38.8%, while the radial stiffness at the end portions decreases by 128% and 164.7%, the axial elongation by 25.6% and 56.6% and the bending deflection by 3.96% and 10.15%. It has been demonstrated by finite element analysis that the variable pitch stent can better meet the clinical requirements.
Publisher: Informa UK Limited
Date: 04-12-2007
Publisher: MDPI AG
Date: 24-01-2020
DOI: 10.3390/MA13030556
Abstract: The behaviour of plain carbon as well as structural steels is qualitatively different at different regimes of strain rates and temperature when they are subjected to hot-working and impact-loading conditions. Ambient temperature and carbon content are the leading factors governing the deformation behaviour and substructural evolution of these steels. This review aims at investigating the mechanical behaviour of structural (or constructional) steels during their strain rate (ranging from very low to very high) as well as hot-working conditions and subsequently establishing the structure–property correlation. Rate-dependent constitutive equations play a significant role in predicting the material response, particularly where the experiments are difficult to perform. In this article, an extensive review is carried out on the merits and limitations of constitutive models which are commonly used to model the deformation behaviour of plain carbon steels.
Publisher: Informa UK Limited
Date: 04-03-2013
Publisher: IEEE
Date: 07-2018
Publisher: Springer Science and Business Media LLC
Date: 07-01-2019
Publisher: Elsevier BV
Date: 03-2014
Publisher: Springer Science and Business Media LLC
Date: 04-02-2023
DOI: 10.1007/S00170-023-10946-9
Abstract: Substantial range, handling and acceleration improvements in high-performance vehicles can be achieved by weight reduction. An important area for weight reduction on a car is the wheels. A novel prototype carbon fibre/epoxy wheel has been developed using a combination of automated fibre placement (AFP) and hand layup for the Sunswift 7 solar car. A three-piece wheel design that utilises each process where best suited has been analysed and optimised using the ANSYS ACP PrepPost suite, manufactured, and mechanically tested. The wheel disc was produced using AFP and featured selective reinforcement in the form of spokes. The AFP fibre paths for the disc have been optimised using CGTech’s VERICUT VCP and VCS to minimise gaps and overlaps, resulting in a 98.9% reduction in overlaps when compared with the unoptimised layup. The rim and tyre mounting region of the wheel have been manufactured using hand layup and adhesively bonded to the disc. This hybrid manufacturing approach has demonstrated an advancement in the feasibility of combining traditional and automated composite manufacturing. The final wheel weighed 3352 g, and the wheel deflection under a compressive load has been experimentally verified within 3% of the theoretical value.
Publisher: Elsevier BV
Date: 06-2021
Publisher: IEEE
Date: 12-2018
Publisher: SAGE Publications
Date: 10-09-2012
Abstract: The paper presents the finite element analysis of top-hat stiffeners (transversely loaded keel support structure) under a static load where splitting–delamination is the primary mode of failure. A set of experiments is conducted on the composite top-hat stiffeners with three different lay-up arrangements. The experimental study, together with the finite element modelling to capture the delamination failure, is presented. Fracture initiation is predicted using an interlaminar-strength-based criterion. A fracture-mechanics-based formulation is used to predict delamination propagation by connecting the composite layers with two-dimensional and three-dimensional interface elements using the commercially available MSC Marc Mentat 2008 r1 finite element software package. Reasonable agreement between the experiments and finite element analysis was achieved. The reserve strength identified by the experimental testing is successfully modelled. The factors affecting the fibre–matrix interface strength are studied. The failure location and mode for fracture initiation and propagation are determined.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 2012
Publisher: SAGE Publications
Date: 21-02-2012
Abstract: Modern day aerospace, automotive, marine, mechanical and civil structures rely on the advanced composites for their added benefits over conventional metallic structures. The complex damage process in composites involves various failure modes such as matrix cracking, fibre-matrix debonding, fibre fracture and delamination. This paper presents an acoustic emission technique for the failure characterisation of top-hat stiffener specimens using conventional piezoelectric acoustic emission sensors and modern fibre Bragg Gratings. Strain insensitive fibre Bragg Grating sensors are used in this experimental investigation to compare the performance of piezoelectric sensors for composite structures. This work has contributed to the development of an acoustic emission sensing system based on fibre Bragg Gratings. Main objectives of this work are to compare the sensing characteristics simultaneously in a composite structure with a surface-bonded acoustic emission–fibre Bragg Grating sensor and acoustic emission–piezoelectric sensor. The feasibility of the system is demonstrated in typical applications of in-situ structural health monitoring based on acoustic emission techniques.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 05-2020
Publisher: Springer Science and Business Media LLC
Date: 28-02-2019
DOI: 10.1038/S41598-019-40162-Z
Abstract: Traditional polymerisation shrinkage (PS) measurement systems measure average PS of dental composites, but the true local PS varies along the length and breadth of the composite. The PS depends on the curing light intensity distribution, resultant degree of conversion (DOC) and the curing rate. In this paper, optical fibre Bragg grating (FBG) sensing based technology is used to measure the linear post-gel PS at multiple locations within dental composite specimens, and is correlated with DOC and curing rate. A commercial dental composite is used, and its post-gel PS and DOC are mapped using embedded fibre Bragg grating sensors at different curing conditions. The distance between the curing l and the composite specimen is varied which resulted in different intensity distribution across the specimen. The effect of curing light intensity distribution on PS, curing rate and DOC are investigated for demonstrating a relationship among them. It is demonstrated that FBG sensing method is an effective method to accurately profiling post-gel PS across the specimen.
Publisher: Springer Science and Business Media LLC
Date: 21-03-2013
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 2011
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2020
Publisher: CRC Press
Date: 03-10-2016
Publisher: Springer Science and Business Media LLC
Date: 27-01-2017
Publisher: MDPI AG
Date: 25-01-2021
DOI: 10.3390/S21030782
Abstract: Distributed fibre optic sensors (DFOS) are popular for structural health monitoring applications in large engineering infrastructure because of their ability to provide spatial strain measurements continuously along their lengths. Curved paths, particularly semicircular paths, are quite common for optical fibre placement in large structures in addition to straight paths. Optical fibre sensors embedded in a curved path configuration typically measure a component of strain, which often cannot be validated using traditional approaches. Thus, for most applications, strain measured along curved paths is ignored as there is no proper validation tool to ensure the accuracy of the measured strains. To overcome this, an analytical strain transformation equation has been developed and is presented here. This equation transforms the horizontal and vertical strain components obtained along a curved semicircular path into a strain component, which acts tangentially as it travels along the curved fibre path. This approach is validated numerically and experimentally for a DFOS installed on a steel specimen with straight and curved paths. Under tensile and flexural loading scenarios, the horizontal and vertical strain components were obtained numerically using finite element analysis and experimentally using strain rosettes and then, substituted into the proposed strain transformation equation for deriving the transformed strain values. Subsequently, the derived strain values obtained from the proposed transformation equation were validated by comparing them with the experimentally measured DFOS strains in the curved region. Additionally, this study has also shown that a localised damage to the DFOS coating will not impact the functionality of the sensor at the remaining locations along its length. In summary, this paper presents a valid strain transformation equation, which can be used for transforming the numerical simulation results into the DFOS measurements along a semicircular path. This would allow for a larger scope of spatial strains measurements, which would otherwise be ignored in practice.
Publisher: Springer Science and Business Media LLC
Date: 20-06-2019
Publisher: Elsevier BV
Date: 2020
Publisher: Informa UK Limited
Date: 19-10-2010
Publisher: Elsevier BV
Date: 03-2020
Publisher: Informa UK Limited
Date: 09-01-2015
Publisher: SAGE Publications
Date: 10-06-2020
Abstract: This article investigates different types of compound die piercing punches and double cutting operation parameters in terms of optimization using finite element technique, Taguchi method, regression analysis, and analysis of variance. The article overcomes the current knowledge gap in studying various cutting edges of piercing punches such as flat, chamfered, flat edge with concave hemisphere, and convex shaped when using the compound dies in st ing operations. The analysis of the compound die is carried out using ANSYS software. The main focus is to determine the contribution of key parameters for obtaining optimum cutting tool design. The best piercing punch is selected based on minimum burr height of the product. The values of cutting process parameters and burr heights have been analyzed using Minitab software. The results obtained indicate that the burr heights of the final product are at a minimum when the sheet metals are thicker and larger when the sheets are thinner. The chamfered and convex punches provided minimum burr heights which are as low as 0.034 mm for a typical sheet metal. This study provides a better outcome compared to the available experimental data in the literature. The investigation also designed efficient compound dies resulting in improved product quality.
Publisher: Wiley
Date: 05-09-2022
DOI: 10.1002/JOR.25166
Abstract: Extreme lateral interbody fusion allows for the insertion of a large‐footprint interbody cage while maintaining the presence of natural stabilizing ligaments and the facets. It is unclear how the load‐distribution mechanisms through these structures alter with temporal changes in the bone graft. The aim of this study was to examine the effects of temporal bone graft changes on load distribution among the cage, graft, and surrounding spinal structures using finite element analysis. Thoracolumbosacral spine computed tomography data from an asymptomatic male subject were segmented into anatomical regions of interest and digitally stitched to generate a surface mesh of the lumbar spine (L1‐S1). The interbody cage was inserted into the L4‐L5 region during surface meshing. A volumetric mesh was generated and imported into finite element software for pre‐processing, running nonlinear static solves, and post‐processing. Temporal stiffening was simulated in the graft region with unbonded (Soft Callus, Temporal Stages 1–3, Solid Graft) and bonded (Partial Fusion, Full Fusion) contact. In flexion and extension, cage stress reduced by 20% from the soft callus to solid graft state. Force on the graft was directly related to its stiffness, and load‐share between the cage and graft improved with increasing graft stiffness, regardless of whether contact was fused with the endplates. Fused contact between the cage‐graft complex and the adjacent endplates shifted load‐distribution pathways from the ligaments and facets to the implant, however, these changes did not extend to adjacent levels. These results suggest that once complete fusion is achieved, the existing load paths are seemingly diminished.
Publisher: SAGE Publications
Date: 20-08-2016
Abstract: The potential for increased productivity offered by automated fibre placement method has opened up a wider range of applications as well as new markets for composite materials. However, like many other manufacturing methods, different flaws such as voids or delamination may still occur during or after lay-up. Therefore, the use of automated fibre placement as an open-mould process where fibre/tape material is fed brings with it a need and an opportunity to establish a reliable inspection and monitoring method to ensure structural integrity not only after fabrication but also one step earlier, during the manufacturing process. Since optical fibre–based photonic sensing technologies are increasingly common for structural health monitoring of composite structures, selection of optical fibre Bragg grating sensors for manufacturing process monitoring has been successfully implemented here. Experiments are carried out on glass fibre/high-density polyethylene laminates with embedded fibre Bragg grating in the automated fibre placement method. The lay-up process conditions are monitored by the fibre Bragg grating sensors via measuring the reflected wavelengths which are related to pressure and temperature. The results presented in this article indicate that fibre Bragg grating sensing technique can be reliably employed for online monitoring of lay-up process to ensure the quality of final product.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 02-2004
Publisher: Elsevier BV
Date: 05-2004
Publisher: Elsevier BV
Date: 07-2022
Publisher: Informa UK Limited
Date: 06-06-2001
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 2023
Publisher: Springer Science and Business Media LLC
Date: 02-06-2020
Publisher: Elsevier BV
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 02-2008
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 2022
DOI: 10.1016/J.JMBBM.2021.104892
Abstract: To test the hypothesis that restoration of class II mesio-occlusal-distal (MOD) cavities can be strengthened through judicious choice of restoration geometry and material properties. An intact extracted human maxillary molar tooth was digitized, segmented, reconstructed, and four 3D restored tooth models were developed with four different restoration geometries: one straight, one single-curved, and two double-curved. Stress analysis was conducted for representative loading using finite element analysis, and maximum principal stresses were determined at the dentine-enamel and restoration-enamel junctions. A range of restorative material elastic moduli (5-80 GPa) and Poisson's ratios (0.25-0.35) were studied. Vertical loads of 400 N were applied on occlusal points, while the roots of the molar teeth, below the crevices, were supported in all directions. All the materials were modelled as homogeneous, isotropic, and elastic. The maximum principal stresses at the restoration-enamel junctions were strongly dependent on the MOD restoration geometries. Peak stresses occurred along the palatal surface of the restoration rather than the opposite buccal surface. Double-curved restorations showed the lowest peak stress at restoration-enamel junctions. Choice of the mechanical properties of restorative material in the range of 5-35 GPa further reduced stress concentrations on the enamel. Class II MOD restorations may be stronger if designed with double-curved marginal geometries that can reduce stress concentrations. Designs with convex and concave geometries were particularly effective because they reduced stress concentrations dramatically. Results suggest that relatively minor changes to the geometry of a restoration can have a substantial effect on stress at the restoration-enamel junction and motivate future experimental analysis.
Publisher: Elsevier BV
Date: 2020
Publisher: SAGE Publications
Date: 13-02-2018
Abstract: With the increasing use of automated fiber placement method for manufacturing highly precise bespoke composite components in the aerospace industry, the level of manufacturing defects within the laminate structure needs to be monitored and minimized for structural integrity. One of the main common defects in automated fiber placement process is misalignment between the tape paths in successive courses which leads to non-integrity of laminate and consequently significant reduction in mechanical strength of the laminate. Therefore, it is necessary to find an appropriate inspection method to monitor and identify these processing defects at the earlier stages of manufacturing. Since optical fiber Bragg grating sensors are being increasingly utilized for structural health monitoring in composite materials and as they were successfully implemented by Oromiehie et al. in their earlier work for on-line lay-up process monitoring, the same methodology is once again tried for identifying the misalignment defects in automated fiber placement process. The experiments are carried out on glass-fiber/nylon laminate with embedded fiber Bragg gratings for the automated tape placement method. The defects due to misalignment are identified by the fiber Bragg grating sensors through their reflected wavelength changes during the automated manufacturing process. The analysis of results indicates that the fiber Bragg grating sensors can be reliably implemented for on-line defect monitoring during the automated fiber placement process to ensure the quality of final product and maintain the expected design life.
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2059431
Publisher: OSA
Date: 2016
Publisher: Informa UK Limited
Date: 31-03-2019
Publisher: Elsevier BV
Date: 12-2020
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.41
Abstract: The development of new composite materials requires analysis and experimentation spanning scales from nanometres to metres, from “atoms to assemblies”. In this paper, concerned primarily with fibre reinforced epoxy composites, a methodology is presented which allows continuum level structural simulation to account for nanoand micro-scale size effects in composites. The novelty of this approach is the modular hierarchical nature of the simulation which ensures computational tractability, regardless of the length scales considered. Linking the nanoscale to the macroscopic scale in a single simulation allows for holistic materials development, including the addition of nanoadditives to polymer resin systems.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 11-2001
Publisher: IEEE
Date: 04-2016
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2020
Abstract: The clinical utility of measuring pressure at the prosthetic socket-residual limb interface is currently unknown. This study aimed to identify whether measuring interface pressure during prosthetic design and fabrication results in closer agreement in pressure measurements between sockets made by different clinicians, and a reduction in pressure over areas of concern. It also investigated whether clinicians value knowing the interface pressure during the fabrication process. Mixed methods. Three prosthetists designed a complete prosthetic system for a transtibial residual limb surrogate. Standardised mechanical testing was performed on each prosthetic system to gain pressure measurements at four key anatomical locations. These measurements were provided to the clinicians, who subsequently modified their sockets as each saw fit. The pressure at each location was re-measured. Each prosthetist completed a survey that evaluated the usefulness of knowing interface pressures during the fabrication process. Feedback and subsequent socket modifications saw a reduction in the pressure measurements at three of the four anatomical locations. Furthermore, the pressure measurements between prosthetists converged. All three prosthetists found value in the pressure measurement system and felt they would use it clinically. Results suggest that sensors measuring pressure at the socket-limb interface has clinical utility in the context of informing prosthetic socket design and fabrication. If the technology is used at the check socket stage, iterative designs with repeated measurements can result in increased consistency between clinicians for the same residual limb, and reductions in the magnitudes of pressures over specific anatomical landmarks. This study provides new information on the value of pressure feedback to the prosthetic socket design process. It shows that with feedback, socket modifications can result in reduced limb pressures, and more consistent pressure distributions between prosthetists. It also justifies the use of pressure feedback in informing clinical decisions.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
DOI: 10.1038/S41598-017-13749-7
Abstract: This study identifies for the first time, the hybrid structure of the white layer in high carbon steel and describes its formation mechanism and properties. The so-called ‘white layer’ in steel forms during high strain rate deformation and appears featureless under optical microscopy. While many researchers have investigated the formation of the white layer, there has been no definitive study, nor is there sufficient evidence to fully explain the formation, structure and properties of the layer. In this study, the formation, morphology and mechanical properties of the white layer was determined following impact testing, using a combination of optical and SE- microscopy, HR-EBSD, TKD and TEM as well as nano-indentation hardness measurements and FE modelling. The phase transformation and recrystallization within and near the white layer was also investigated. The microstructure of the steel in the white layer consisted of nano-sized grains of martensite. A very thin layer of austenite with nano sized grains was identified within the white layer by HR-EBSD techniques, the presence of which is attributed to a thermally-induced reverse phase transformation. Overall, the combination of phase transformations, strain hardening and grain refinement led to a hybrid structure and an increase in hardness of the white layer.
Publisher: Springer Science and Business Media LLC
Date: 14-01-2021
DOI: 10.1038/S41598-020-80838-5
Abstract: A strain profile measurement technique using a chirped fibre Bragg grating (CFBG) sensor by implementing an integration of differences (IOD) method is reported in this paper. Using the IOD method the spatial distribution of strain along the length of the CFBG is extracted from its power reflectance spectra. As a proof of concept demonstration, the developed technique is applied to measure the polymerisation shrinkage strain profile of a photo-cured polymer dental composite which exhibits a non-uniform strain distribution attributed to the curing l characteristics. The result from the CFBG technique is compared with that of an FBG array embedded in the dental composite and is correlated with the degree of conversion of the material which also depends on the curing l intensity distribution. This technology will have significant impact and applications in a range of medical, materials and engineering areas where strain or temperature gradient profile measurement is required in smaller scales.
Publisher: SAGE Publications
Date: 03-08-2016
Abstract: The increasing use of sandwich composites for structural applications brings with it a need to establish a reliable inspection and monitoring method to ensure structural integrity and safe operation throughout the service life. Since optical fibre-based photonic sensing technologies are increasingly common for structural health monitoring of composite structures, selection of optical fibre Bragg grating sensors could be one possible choice for this purpose. In this paper, performance characterisation of sandwich composite with embedded silica fibre Bragg grating sensor is reported. Experimental tests were performed on a carbon fibre foam core sandwich composite embedded with a silica fibre Bragg grating sensor to extract the structural health monitoring parameters such as strain and temperature. The current study found that sandwich composite exhibits foam relaxation however, its impact on strain measurement is negligible. Another important finding from the theoretical and the experimental thermal modelling was that although the constituent components of the sandwich composite have entirely different thermal expansion coefficients, its effect on the embedded fibre sensor can be minimal if the sensors are embedded between the face sheets. These results can initiate further research in this area and can lead to the development of state-of-the art structural health monitoring techniques for sandwich composite structures.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2019
Publisher: Elsevier BV
Date: 05-2019
Publisher: Elsevier BV
Date: 10-2008
Publisher: Elsevier BV
Date: 09-2010
Publisher: Springer US
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 08-2015
Publisher: Informa UK Limited
Date: 18-12-2016
Publisher: Informa UK Limited
Date: 15-01-2021
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 04-2019
No related grants have been discovered for Gangadhara Prusty.