Numerous materials show a softening behaviour at dynamic loading. The decrease of stress is caused by the evolution in the microscale in terms of areas where the local stiffness is reduced, e.g. due to micro-void growth. For a numerical treatment of this material behaviour, phenomenological damage approaches are used in daily engineering practice. For a better understanding of the micromechanic...

The collagen network of the annulus fibrosus largely controls the functional biomechanics of the lumbar intervertebral discs (IVDs). Quantitative anatomical examinations have shown bundle orientation patterns, possibly coming from regional adaptations of the annulus mechanics. This study aimed to show that the regional differences in annulus mechanical behaviour could be reproduced by consideri...

In breast elastography, breast tissue usually undergoes large compression resulting in significant geometric and structural changes. This implies that breast elastography is associated with tissue nonlinear behavior. In this study, an elastography technique is presented and an inverse problem formulation is proposed to reconstruct parameters characterizing tissue hyperelasticity. Such parameter...

this research work is devoted to experimental and theoretical evaluations of a hybrid constitutive model which was designed to simulate the mechanical behavior of a tread rubber compound. the model is a combination of yeoh hyperelastic model with a strain-rate hysteresis model developed by bergstrom and boyce. the parameters of the yeoh model were calibrated from experimental data of the astm d...

Hyperelastic materials based on Signorini’s strain energy density are studied by using Shannon wavelets. Cylindrical waves propagating in a nonlinear elastic material from the circular cylindrical cavity along the radius are analyzed in the following by focusing both on the main nonlinear effects and on the method of solution for the corresponding nonlinear differential equation. Cylindrical wa...

The response of a neo-Hookean fiber composite undergoing finite out-of-plane shear deformation is examined. To this end an explicit close form solution for the out-of-plane shear response of a cylindrical composite element is introduced. We find that the overall response of the cylindrical composite element can be characterized by a fictitious homogeneous neo-Hookean material. Accordingly, this...

We model numerically the mechanical effects of UV induced photo-polymerization in elastomeric artificial lens. The elastomer is originated upon cross-linking of a silicone matrix. UV irradiation of one side of the lens polymerizes selectively a photosensitive macromer, causing local variations of its concentration. The subsequent diffusion of macromers from high concentration to low concentrati...

We present several time integration algorithms of second-order accuracy that are numerically simple and effective for nonlinear elastodynamic problems. These algorithms are based on a general four-step scheme that has a resemblance to the backward differentiation formulas. We also present an extension to the composite strategy of the Bathe method. Appropriate values for the algorithmic paramete...