Breaking Analysis of Artificial Elastic Tubes and Human Artery

Li, W. G.; Going, James J.; Hill, Nicholas A.; Luo, Xiaoyu

doi:10.1142/s1758825113500245

Cited by 4 publications

(1 citation statement)

References 21 publications

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“…Similar to Ref. 27 , the optimization process is carried out using the MATLAB ( lsqnonlin function). The approximation between the measurement and the prediction is measured by the standard deviation error: normalised by the mean stress .…”

Section: A New Constitutive Model For Skin Damagementioning

confidence: 99%

An Invariant-Based Damage Model for Human and Animal Skins

Luo

2016

Ann Biomed Eng

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Constitutive modelling of skins that account for damage effects is important to provide insight for various clinical applications, such as skin trauma and injury, artificial skin design, skin aging, disease diagnosis, surgery, as well as comparative studies of skin biomechanics between species. In this study, a new damage model for human and animal skins is proposed for the first time. The model is nonlinear, anisotropic, invariant-based, and is based on the Gasser–Ogden–Holzapfel constitutive law initially developed for arteries. Taking account of the mean collagen fibre orientation and its dispersion, the new model can describe a wide range of skins with damage. The model is first tested on the uniaxial test data of human skin and then applied to nine groups of uniaxial test data for the human, swine, rabbit, bovine and rhino skins. The material parameters can be inversely estimated based on uniaxial tests using the optimization method in MATLAB with a root mean square error ranged between 2.15% and 12.18%. A sensitivity study confirms that the fibre orientation dispersion and the mean fibre angle are among the most important factors that influence the behaviour of the damage model. In addition, these two parameters can only be reliably estimated if some histological information is provided. We also found that depending on the location of skins, the tissue damage may be brittle controlled by the fibre breaking limit (i.e., when the fibre stretch is greater than 1.13–1.32, depending on the species), or ductile (due to both the fibre and the matrix damages). The brittle damages seem to occur mostly in the back, and the ductile damages are seen from samples taken from the belly. The proposed constitutive model may be applied to various clinical applications that require knowledge of the mechanical response of human and animal skins.

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Section: A New Constitutive Model For Skin Damagementioning

confidence: 99%

An Invariant-Based Damage Model for Human and Animal Skins

Luo

2016

Ann Biomed Eng

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Compressive strength of elderly vertebrae is reduced by disc degeneration and additional flexion

Maquer

Schwiedrzik

Huber

et al. 2015

Journal of the Mechanical Behavior of Biomedical Materials

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Computer tomography (CT)-based finite element (FE) models assess vertebral strength better than dual energy X-ray absorptiometry. Osteoporotic vertebrae are usually loaded via degenerated intervertebral discs (IVD) and potentially at higher risk under forward bending, but the influences of the IVD and loading conditions are generally overlooked. Accordingly, Magnetic Resonance Imaging was performed on 14 lumbar discs to generate FE models for the healthiest and most degenerated specimens. Compression, torsion, bending, flexion and extension conducted experimentally were used to calibrate both models. They were combined with CT-based FE models of 12 lumbar vertebral bodies to evaluate the effect of disc degeneration compared to a loading via endplates embedded in a stiff resin, the usual experimental paradigm. Compression and lifting were simulated, load and damage pattern were evaluated at failure. Adding flexion to the compression (lifting) and higher disc degeneration reduces the failure load (8-14%, 5-7%) and increases damage in the vertebrae.Under both loading scenarios, decreasing the disc height slightly increases the failure load; embedding and degenerated IVD provides respectively the highest and lowest failure load.Embedded vertebrae are more brittle, but failure loads induced via IVDs correlate highly with vertebral strength. In conclusion, osteoporotic vertebrae with degenerated IVDs are consistently weaker -especially under lifting, but clinical assessment of their strength is possible via FE analysis without extensive disc modelling, by extrapolating measures from the embedded situation.

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Hyperelastic models for hydration of cellular tissue

Sman

2015

Soft Matter

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In this paper we present hyperelastic models for swelling elastic shells, due to pressurization of the internal cavity. These shells serve as model systems for cells having cell walls, as can be found in bacteria, plants and fungi. The pressurized internal cavity represents the cell vacuole with intact membrane at a certain turgor pressure, and the elastic shell represents the hydrated cell wall. At pressurization the elastic shell undergoes inhomogeneous deformation. Its deformation is governed by a strain energy function. Using the scaling law of Cloizeaux for the osmotic pressure, we obtain approximate analytical expressions of the cell volume versus turgor pressure - which are quite comparable to numerical solutions of the problem. Subsequently, we have simulated the swelling of shells - where the cell wall material is embedded with microfibrils, leading to strain hardening and anisotropic cell expansion. The purpose of our investigations is to elucidate the contribution of cell membrane integrity and turgor to the water holding capacity (hydration) of plant foods. We conclude with a discussion of the impact of this work on the hydration of food material, and other fields like plant science and the soft matter physics of responsive gels.

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Breaking Analysis of Artificial Elastic Tubes and Human Artery

Cited by 4 publications

References 21 publications

An Invariant-Based Damage Model for Human and Animal Skins

An Invariant-Based Damage Model for Human and Animal Skins

Compressive strength of elderly vertebrae is reduced by disc degeneration and additional flexion

Hyperelastic models for hydration of cellular tissue

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