1,720,985 research outputs found
Limbert, G S, NX13227
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/399463Surname: LIMBERT. Given Name(s) or Initials: G S. Military Service Number or Last Known Location: NX13227. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 5434.217250
Item: [2016.0049.31756] "Limbert, G S, NX13227
An explicit three dimensional finite element model of an incompressible tranversely isotropic hyperelastic material: application to the study of the human ACL ligament
No full text
On the constitutive modelling of biological soft connective tissues. A general theoretical framework for strongly anisotropic fiber-reinforced composites at finite strain
No full textThis research describes a general theoretical framework for the constitutive modeling of biological soft connective tissues. The approach is based on the theory of continuum fiber-reinforced composites at finite strain. Explicit expressions of the stress tensors in the material and spatial configurations are first established in the general case, without precluding any assumption regarding possible kinematic constraints or any particular mechanical symmetry of the material. Original expressions of the elasticity tensors in the material and spatial configurations are derived and new coupling terms, characterizing the interactions between the constituents of the continuum composite material, are isolated and their biological significance highlighted. Further to this, expressions of the elasticity tensors are degenerated in order to take into account special type of material symmetries. Kinematic constraints and constitutive requirements are also briefly discussed. <br/
On skin microrelief and the emergence of expression micro-wrinkles
No full textOver the course of a life time, as a result of adaptive mechanobiological processes (e.g. ageing), or the action of external physical factors such as mechanical loading, the human skin is subjected to, and hosts complex biophysical processes. These phenomena typically operate through a complex interplay, that, ultimately, is responsible for the evolutive geometrical characteristics of the skin surface. Wrinkles are a manifestation of these effects. Although numerous theoretical models of wrinkles arising in multi-layered structures have been proposed, they typically apply to idealised geometries. In the case of skin, which can be viewed as a geometrically complex multi-layer assembly, it is pertinent to question whether the natural skin microrelief could play a significant role in conditioning the characteristics of compression-induced micro-wrinkles by acting as an array of geometrical imperfections. Here, we explore this question through the development of an anatomically-based finite strain parametric finite element model of the skin, represented as a stratum corneum layer on top of a thicker and softer substrate. Our study suggests that skin microrelief could be the dominant factor conditioning micro-wrinkle characteristics for moderate elastic modulus ratios between the two layers. Beyond stiffness ratios of 100, other factors tend to overwrite the effects of skin microrelief. Such stiffness ratio fluctuations can be induced by changes in relative humidity or particular skin conditions and can therefore have important implications for skin tribology.</p
Three dimensional finite element model of the anterior cruciate ligament: influence of the initial strain field
No full textIn vivo structural analysis of human tibiae: determination of homogenized mechanical characteristics
No full textRatcheting wear of a cobalt-chromium alloy during reciprocated self-mated dry sliding
No full textCobalt-chromium alloys find usage in environments where reliable wear and friction properties are required. However, the sliding wear particles generated presents significant health risks in nuclear and medical applications. Thus, there is great motivation to develop cobalt-free alternatives. These alloys are known to undergo several physical changes at the interface during dry sliding, sensitive to the loading conditions and environment. Due to these micro-structural alterations, the wear behaviour of the alloy is modified, which linear Archard-like wear models do not capture. To better understand the wear performance a cobalt-chromium alloy in-situ, and to aid their replacement, a mechanistic model of wear would be desirable. To understand the essential physical phenomena required in the modelling of cobalt-chrome systems, a systematic experimental study was performed for a hot-isostatically pressed cobalt-chromium hard-facing alloy. To date, no such in-depth self-mated tribological study has been conducted for this alloy under these processing conditions. Tests were done under combinations of sliding speed (0.02–0.5 m/s) and normal load (40–1000N). Platelet wear and subsurface cracking was seen in all tests, with considerable work-hardening in the subsurface, as well as evidence of plastic deformation at the wear surface. These results suggest the platelet wear observed is more likely a consequence of a plastic ratcheting mechanism, known as ‘ratchetting wear’ and not delamination wear. Unique to this study, the cross-sectional nano-indentation study showed the stiffness of material at and below wear interface to drop significantly. The changes in material properties and a plastically-driven wear mechanism have implications for the development of a mechanistic wear model.</p
Flexural and creep properties of human jaw compact bone for FEA studies
No full textThe aim of this work was to improve the constitutive model of the human mandible and dentition system by taking into account the non-linear material properties of the structural boney matrix that forms the human jaw bone or mandible. Due to the specific structure of the jaw bone the time dependence of the mechanical properties also forms an important stage of the quantification process. The lack of specific experimental data of this type of material prevents the implementation of these properties into finite element simulations which results in poor quality modelling. Here an attempt was made to determine elastic and viscoelastic mechanical characteristics of the compact bone tissue forming the mandible. The elastic properties of compact bone were determined experimentally from 3 point bending tests and the viscoelastic properties were evaluated from creep tests in compression. A particular human jaw from this complex study was used to reconstruct a geometric model for further numerical experiments
Thermoelastic modelling of the skin at finite deformations
No full textThe modelling and computation of the coupled thermal and mechanical response of human skin at finite deformations is considered. The model extends current thermal models to account for thermally- and mechanically-induced deformations. Details of the solution of the highly nonlinear system of governing equations using the finite element method are presented. A representative numerical example illustrates the importance of considering the coupled response for the problem of a rigid, hot indenter in contact with the skin
- …
