ORCID Profile
0000-0002-8844-3206
Current Organisations
Griffith University - Gold Coast Campus
,
University of Erlangen-Nuremberg
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Physical Metallurgy | Composite and Hybrid Materials | Vertebrate Biology | Biomaterials | Biomedical Engineering | Reaction Kinetics And Dynamics | Materials Engineering | Numerical Analysis
ANZSRC Socio-Economic Objective (SEO)
Skeletal System and Disorders (incl. Arthritis) | Metals (composites, coatings, bonding, etc.) | Expanding Knowledge in Engineering | Other non-ferrous metals (e.g. copper,zinc) |
Related Links
Publications
Study of structures made of composite materials used in automotive industry
Publisher: SAGE Publications
Date: 29-05-2021
DOI: 10.1177/14644207211019767
Abstract: Composite materials are becoming more and more popular in automotive industry since classical materials are, in general, expensive and deficient. This paper presents a study on how metals, used in the construction of car doors, can be successfully replaced by composite materials. The vibration behavior of a car door, made of composite materials, is studied and, since the rigidity of this component is low, a solution is proposed in which the structure is stiffened. The modal analysis and finite element method are used to identify the eigenfrequencies and eigenmodes for this structure.
Revealing Hydrogen States in Carbon Structures by Analyzing the Thermal Desorption Spectra
Publisher: MDPI AG
Date: 11-01-2022
DOI: 10.3390/C8010006
Abstract: An effective methodology for the detailed analysis of thermal desorption spectra (TDS) of hydrogen in carbon structures at micro- and nanoscale was further developed and applied for a number of TDS data of one heating rate, in particular, for graphite materials irradiated with atomic hydrogen. The technique is based on a preliminary description of hydrogen desorption spectra by symmetric Gaussians with their special processing in the approximation of the first- and the second-order reactions. As a result, the activation energies and the pre-exponential factors of the rate constants of the hydrogen desorption processes are determined, analyzed and interpreted. Some final verification of the results was completed using methods of numerical simulation of thermal desorption peaks (non-Gaussians) corresponding to the first- and the second-order reactions. The main research finding of this work is a further refinement and/or disclosure of poorly studied characteristics and physics of various states of hydrogen in microscale graphite structures after irradiation with atomic hydrogen, and comparison with the related results for nanoscale carbon structures. This is important for understanding the behavior and relationship of hydrogen in a number of cases of high energy carbon-based materials and nanomaterials.
Some estimates on solutions of mixed problems for mixtures
Publisher: Informa UK Limited
Date: 23-11-2018
Finite element analysis of an elbow tube in concrete anchor used in water supply networks
Publisher: SAGE Publications
Date: 25-08-2019
Abstract: This paper aims to analyze the stress and strain states appearing in the elbow of a tube, such as those commonly used in a city’s water supply network. The stress field is characterized by the fact that there is a significant stress increase when compared to a straight tube. As a result, the strength of such an elbow must be investigated and guaranteed for such a network to be well designed. A practical solution used is to anchor the elbow in a massive concrete block. The paper compares the stress field that occurs in the elbow when it is free, buried in the ground, and when it is anchored in a massive concrete block. Furthermore, we investigate how a crack appears and propagates in the elbow. This happens especially for the elbow buried in the ground where the stress and strain are higher than when the elbow is anchored in concrete. The results obtained can be used in the current practice in the case of water supply networks made by high-density polyethylene pipes.
Foreword
Publisher: Springer Science and Business Media LLC
Date: 21-06-2021
An element-wise scheme to analyse local mechanical anisotropy in fibre-reinforced composites
Publisher: Informa UK Limited
Date: 13-05-2020
On the buckling behavior of perfect and atomically defective hetero-junction carbon nanotubes
Publisher: Informa UK Limited
Date: 29-06-2017
Impact of Coping Veneering Techniques on the Survival of Implant-Supported Zirconia-Based-Crowns Cemented to Hybrid-Abutments: An-In-Vitro Study
Publisher: MDPI AG
Date: 25-09-2020
DOI: 10.3390/BIOENGINEERING7040117
Abstract: The objective of this study is to investigate the influence of veneering technique (hand-layering vs. milling) on the fracture resistance of bi-layer implant-supported zirconia-based hybrid-abutment crowns. Mandibular molar copings were anatomically designed and milled. Copings were then veneered by hand-layering (HL) (n = 20) and milling using the Cad-On technique (LD) (n = 20). Crowns were cemented to zirconia hybrid-abutments. Ten s les of each group acted as a control while the remaining ten s les were subjected to fatigue in a chewing simulator. Crowns were loaded between 50 and 100 N for 1.2 million cycles under simultaneous temperature fluctuation between 5 and 55 °C. Crowns were then subjected to static load a to fracture test. Data were statistically analysed using the one-way ANOVA. Randomly selected crowns from each group were observed under scanning electron microscopy to view fractured surfaces. Study results indicate that during fatigue, LD crowns had a 100% survival rate while HL crowns had a 50% failure rate. Fracture resistance of LD crowns was statistically significantly higher than that of HL crowns at the baseline and after fatigue (p ≤ 0.05). However, fatigue did not cause a statistically significant reduction in fracture resistance in both LD and HL groups (p 0.05). Copings fractured in the LD crowns only and the fracture path was different in both LD and HL groups. According to the results, it was concluded that milled veneer implant-supported hybrid-abutment crowns exhibit significantly higher fracture resistance, and better withstand clinical masticatory loads in the posterior region compared to the hand-layered technique. Also, fatigue application and artificial aging caused no significant strength reduction in both techniques. Clinical significance: Different veneering techniques and materials (hand-layering or milling) act differently to clinical forces and environment and may be prone to early chipping during service. Therefore, practitioners are urged to consider the appropriate veneering protocol for posterior implant-supported hybrid-abutment restorations.
Some results in Moore‐Gibson‐Thompson thermoelasticity of dipolar bodies
Publisher: Wiley
Date: 14-07-2020
Feasibility study on hybrid weld-bonding between dissimilar material for automotive industry
Publisher: Elsevier BV
Date: 2023
Mechanical degradation model of porous magnesium scaffolds under dynamic immersion
Publisher: SAGE Publications
Date: 16-10-2019
Abstract: A new generation of bone scaffolds incorporates features like biodegradability and biocompatibility. A combination of these attributes will result in having a temporary bone scaffold for tissue regeneration that mimics the natural cancellous bone. Under normal conditions, scaffolds will be gradually eroded. This surface erosion occurs due to the immersion and the movement of bone marrow. Surface erosion on bone scaffolds leads to changes of the morphology. The mechanical response of the scaffolds due to the surface erosion is not fully understood. The aim of this study is to assess the influence of the dynamic immersion condition on the degradation behaviour and mechanical properties of porous magnesium. In the present work, load-bearing biomaterial scaffolds made of pure magnesium are immersed in simulated body fluids (SBF) with a certain flow rate. S les with different porosities are subjected to tomography and are used to develop virtual 3D models. By means of numerical simulations, the mechanical properties, for instance, elastic modulus, plateau stress, 0.2% offset yield stress and energy absorption of these degraded s les are collected. The findings are then validated with the values obtained from the experimental tests. Finite element method enables the study on the failure mechanism within the biomaterial scaffolds. The knowledge of how weak walls or thin struts collapsed under compressive loading is essential for future biomaterial scaffolds development. Results from the experimental tests are found in sound good agreement with the numerical simulations.
On stability in the thermoelastostatics of dipolar bodies
Publisher: Springer Science and Business Media LLC
Date: 16-08-2018
Heat Treatments and Critical Quenching Rates in Additively Manufactured Al–Si–Mg Alloys
Publisher: MDPI AG
Date: 05-02-2020
DOI: 10.3390/MA13030720
Abstract: Laser powder-bed fusion (LPBF) has significantly gained in importance and has become one of the major fabrication techniques within metal additive manufacturing. The fast cooling rates achieved in LPBF due to a relatively small melt pool on a much larger component or substrate, acting as heat sink, result in fine-grained microstructures and high oversaturation of alloying elements in the α-aluminum. Al–Si–Mg alloys thus can be effectively precipitation hardened. Moreover, the solidified material undergoes an intrinsic heat treatment, whilst the layers above are irradiated and the elevated temperature in the built chamber starts the clustering process of alloying elements directly after a scan track is fabricated. These silicon–magnesium clusters were observed with atom probe tomography in as-built s les. Similar beneficial clustering behavior at higher temperatures is known from the direct-aging approach in cast s les, whereby the artificial aging is performed immediately after solution annealing and quenching. Transferring this approach to LPBF s les as a possible post-heat treatment revealed that even after direct aging, the outstanding hardness of the as-built condition could, at best, be met, but for most instances it was significantly lower. Our investigations showed that LPBF Al–Si–Mg exhibited a high dependency on the quenching rate, which is significantly more pronounced than in cast reference s les, requiring two to three times higher quenching rate after solution annealing to yield similar hardness results. This suggests that due to the finer microstructure and the shorter diffusion path in Al–Si–Mg fabricated by LPBF, it is more challenging to achieve a metastable oversaturation necessary for precipitation hardening. This may be especially problematic in larger components.
On the Problem of “Super” Storage of Hydrogen in Graphite Nanofibers
Publisher: MDPI AG
Date: 29-03-2022
DOI: 10.3390/C8020023
Abstract: This article is devoted to some fundamental aspects of “super” storage in graphite nanofibers (GNF) of “reversible” (~20–30 wt.%) and “irreversible” hydrogen (~7–10 wt.%). Extraordinary results for hydrogen “super” storage were previously published by the group of Rodriguez and Baker at the turn of the century, which been unable to be reproduced or explained in terms of physics by other researchers. For the first time, using an efficient method of processing and analysis of hydrogen thermal desorption spectra, the characteristics of the main desorption peak of “irreversible” hydrogen in GNF were determined: the temperature of the highest desorption rate (Tmax = 914–923 K), the activation energy of the desorption process (Q ≈ 40 kJ mol−1), the pre-exponential rate constant factor (K0 ≈ 2 × 10−1 s−1), and the amount of hydrogen released (~8 wt.%). The physics of hydrogen “super” sorption includes hydrogen diffusion, accompanied by the “reversible” capture of the diffusant by certain sorption “centers” the hydrogen spillover effect, which provides local atomization of gaseous H2 during GNF hydrogenation and the Kurdjumov phenomenon on thermoelastic phase equilibrium. It is shown that the above-mentioned extraordinary data on the hydrogen “super” storage in GNFs are neither a mistake nor a mystification, as most researchers believe.
Novel Low-Cost Sensor for Human Bite Force Measurement
Publisher: MDPI AG
Date: 06-08-2016
DOI: 10.3390/S16081244
Toughness of a brittle epoxy resin reinforced with micro cork particles: Effect of size, amount and surface treatment
Publisher: Elsevier BV
Date: 04-2017
Experimental study of the valve rotation in a valvetrain car engine
Publisher: SAGE Publications
Date: 06-05-2022
DOI: 10.1177/14644207221097902
Abstract: The rotational motion of the valve during engine operation exists and research presented in this paper has shown that it can have significant importance in the costs related to the operation of the system. The main motion of the valve is an alternating translation along its axis of symmetry, but which is accompanied by an independent rotation around its own axis, possibly due to the constructive shape of the valve. This rotational movement is an important phenomenon with practical applications. The existence of this valve rotation movement has a number of advantages, mainly leading to an increase in the operating period of the valve and implicitly of the engine. An experimental study of the valve rotation is presented in the paper and a comparison with theoretical models is made.
Additive manufacturing of cobalt-based dental alloys: Analysis of microstructure and physicomechanical properties
Publisher: Hindawi Limited
Date: 11-11-2018
DOI: 10.1155/2018/8213023
Abstract: The limitations of investment casting of cobalt-based alloys are claimed to be less problematic with significant improvements in metal additive manufacturing by selective laser melting (SLM). Despite these advantages, the metallic devices are likely to display mechanical anisotropy in relation to build orientations, which could consequently affect their performance “in vivo.” In addition, there is inconclusive evidence concerning the requisite composition and postprocessing steps (e.g., heat treatment to relieve stress) that must be completed prior to using the devices. In the current paper, we evaluate the microstructure of ternary cobalt-chromium-molybdenum (Co-Cr-Mo) and cobalt-chromium-tungsten (Co-Cr-W) alloys built with direct metal printing and LaserCUSING SLM systems, respectively, at 0°, 30°, 60°, and 90° inclinations (Φ) in as-built (AB) and heat-treated (HT) conditions. The study also examines the tensile properties (Young’s modulus, E yield strength, R P0.2 elongation at failure, A t and ultimate tensile strength, R m ), relative density (RD), and microhardness (HV5) and macrohardness (HV20) as relevant physicomechanical properties of the alloys. Data obtained indicate improved tensile properties and HV values after a short and cost-effective heat-treatment cycle of Co-Cr-Mo alloys however, the process did not homogenize the microstructure of the alloy. Annealing heat treatment of Co-Cr-W led to significant isotropic characteristics with increased E and A t (except for Φ = 90°) in contrast to decreased R P0.2 , R m , and HV values, compared to the AB form. Similarly, the interlaced weld-bead structures in AB Co-Cr-W were removed during heat treatment, which led to a complete recrystallization of the microstructure. Both alloys exhibited defect-free microstructures with RD exceeding 99.5%.
Fracture toughness of L-PBF fabricated aluminium–silicon: a quantitative study on the role of crack growth direction with respect to layering
Publisher: Springer Science and Business Media LLC
Date: 07-02-2020
DOI: 10.1007/S40964-020-00113-X
Abstract: Laser powder bed fusion has become one of the major techniques within metal additive manufacturing, especially when delicate structures and high geometric accuracy are concerned. Lately, the awareness of the material-specific macroscopic anisotropy has risen and led to widespread investigations on the static mechanical strength. However, little is known about the fracture behavior of the layer-wise fabricated metal components and their affinity of crack propagation between consecutive layers, which is particularly important for aluminium–silicon alloys containing embrittled zones in double-irradiated areas. A recent study indicated that there is a significant drop in fracture toughness in case the crack growth direction is parallel to the layering. To investigate this matter further and to shed light on the fracture toughness behavior in the range of a 0°–45° angle offset between the crack growth direction relative to the layering, notched s les with varying polar angles were subjected to mode I fracture toughness testing. Our results indicate that the fracture toughness is an almost-stable characteristic up to a mismatch of about 20° between the crack propagation path and the layering, at which point the fracture toughness decreases by up to 10%.
On the real possibility of “super” hydrogen intercalation into graphite nanofibers
Publisher: Informa UK Limited
Date: 02-01-2022
Hot Isostatic Pressing of Aluminum–Silicon Alloys Fabricated by Laser Powder-Bed Fusion
Publisher: MDPI AG
Date: 18-09-2020
DOI: 10.3390/TECHNOLOGIES8030048
Abstract: Hot isostatic pressing can be utilized to reduce the anisotropic mechanical properties of Al–Si–Mg alloys fabricated by laser powder-bed fusion (L-PBF). The implementation of post processing densification processes can open up new fields of application by meeting high quality requirements defined by aircraft and automotive industries. A gas pressure of 75 MPa during hot isostatic pressing lowers the critical cooling rate required to achieve a supersaturated solid solution. Direct aging uses this pressure related effect during heat treatment in modern hot isostatic presses, which offer advanced cooling capabilities, thereby avoiding the necessity of a separate solution annealing step for Al–Si–Mg cast alloys. Hot isostatic pressing, followed by rapid quenching, was applied to both sand cast as well as laser powder-bed fused Al–Si–Mg aluminum alloys. It was shown that the critical cooling rate required to achieve a supersaturated solid solution is significantly higher for additively manufactured, age-hardenable aluminum alloys than it is for comparable sand cast material. The application of hot isostatic pressing can be combined with heat treatment, consisting of solution annealing, quenching and direct aging, in order to achieve both a dense material with a small number of preferred locations for the initiation of fatigue cracks and a high material strength.
Influence of bone marrow characteristic and trabecular bone morphology on bone remodelling process with FSI approach
Publisher: SAGE Publications
Date: 24-02-2022
DOI: 10.1177/14644207221080115
Abstract: While doing daily physiological activities, the trabecular bone will experience a certain amount of deformation which leads to the bone marrow movement. The movement can affect the bone remodelling process and the properties of the bone itself. The bone marrow plays a role as a hydraulic stiffening of the trabecular structure. However, previous studies analysed on trabecular bone and bone marrow separately, which is not considered as the actual condition. Thus, it is crucial to consider combine analyses of the bone marrow with the trabecular structure simultaneous. The aim of this study is to investigate the effect of bone marrow on the mechanical environment and the structure of trabecular bone during normal walking loading. Hence, this study used the Fluid-Structure Interaction (FSI) approach as a finite element method to discover the effect of bone marrow to the trabecular structure and vice versa. The findings show the shear stress value along normal walking phase was found in a range of 0.01–0.27 Pa which is sufficient to regulated cell response minimally. This study provides insight into understanding the related mechanobiological responds towards supply of nutrients onto bone cells.
Experimental Study on Thermal Properties of Hollow Sphere Structures
Publisher: Trans Tech Publications, Ltd.
Date: 03-2021
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.407.185
Abstract: Experimental analyses are performed to determine thermal conductivity, thermal diffusivity and volumetric specific heat with transient plane source method on hollow sphere structures. Single-sided testing is used on different s les and different surfaces. Results dependency on the surface is observed.
On thermal strains and residual stresses in the linear theory of anti‐sandwiches
Publisher: Wiley
Date: 06-06-2019
Obtaining global equations for the Young’s modulus of perfect and defective carbon nanotubes
Publisher: IOP Publishing
Date: 05-12-2017
Related Organisations
Related Funding Activities
Discovery Projects - Grant ID: DP1092458
Start Date: 07-2010
End Date: 02-2014
Amount: $330,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE170100057
Start Date: 09-2017
End Date: 09-2018
Amount: $250,000.00
Funder: Australian Research Council
View Funded Activity