A constitutive model for isotropic, semi-crystalline polymers is proposed. The Eulerian in the sense that it independent of measures total deformation and plastic/inelastic deformations. It able to account such essential phenomena as strain-rate dependence, work hardening, stress relaxation, volumetric inelastic deformations, damage. was applied uniaxial tension tests performed on polyoxymethyl...

Bone is a tough biological material. It is generally accepted that bone's toughness arises from its unique hierarchical structure, which in turn facilitates distributed microcracking prior to fracture. Yet, there has been limited progress on the detailed roles of the structural elements in the microcracking process. The present study examines the structure-microcracking relations at the lamella...

INTRODUCTION Bone fracture is a major concern for elderly because the toughness of aged bone becomes more susceptible to impact load.(6) It has been well documented that the post-yield behavior of bone determines the major part of the toughness of bone.(3,4) As a natural composite material, bone primarily comprises a hard mineral phase (mainly hydroxyapatite crystals) and a more compliant colla...

Recently, a dislocation free deformation mechanism was proposed by Kiritani et al., based on a series of experiments where thin foils of fcc metals were deformed at very high strain rates. In the experimental study, they observed a large density of stacking fault tetrahedra, but very low dislocation densities in the foils after deformation. This was interpreted as evidence for a new dislocation...

An experimental investigation of the wall shear stress distribution downstream of a backward-facing step is carried out. The wall shear stress distribution was determined by measuring the deformation of a gel layer, attached to the wall downstream of the step. Speckle pattern interferometry was applied to measure the deformation of the gel layer. The measured deformation, combined with the prop...

Thin shell torispherical pressure vessel heads are known to exhibit complex elasticplastic deformation and buckling behaviour under static pressure. In pressure vessel Design by Analysis, the designer is required to assess both of these behaviour modes when specifying the allowable static load. The EN and ASME Boiler and Pressure Vessel Codes permit the use of inelastic analysis in design by an...

A computational framework is presented to evaluate the shape as well as non-shape (parameter) sensitivity of nite thermo-inelastic deformations using the continuum sensitivity method (CSM). Weak sensitivity equations are developed for the large thermo-mechanical deformation of hyperelastic thermoviscoplastic materials that are consistent with the kinematic, constitutive, contact and thermal ana...

Thin shell torispherical pressure vessel heads are known to exhibit complex elasticplastic deformation and buckling behaviour under static pressure. In pressure vessel Design by Analysis, the designer is required to assess both of these behaviour modes when specifying the allowable static load. The EN and ASME Boiler and Pressure Vessel Codes permit the use of inelastic analysis in design by an...