The present paper is concerned with the development of a micromechanical model of the hardening, rate-sensitivity and thermal softening of b.c.c. crystals. In formulating the model we specifically consider the following unit processes: double-kink formation and thermally activated motion of kinks; the close-range interactions between primary and forest dislocations, leading to the formation of ...

This paper presents a new formulation of a well known double hardening model often referred to as the Hardening Soil model. As an alternative to the existing Hardening Soil model’s Mohr-Coulomb failure surface, the new formulation allows for the incorporation of smooth failure surfaces, such as the failure surface proposed by Matsuoka & Nakai or that proposed by Lade & Duncan. Although the inco...

Lipid and fatty acid composition of chloroplast thylakoid membranes was determined in two varieties of wheat (Triticum aestivum L.), the hardy Miranovskaja and the sensitive Penjamo. Plants were grown at room temperature or under frost hardening conditions (1.5 degrees C). Changes in lipid and fatty acid composition of the isolated thylakoids could be related to the temperature dependence of li...

This study deals with the relation between the microstructure of semi-crystalline polymers and their intrinsic deformation and fracture behaviour. For this purpose, the deformation and failure of well-characterised PET, PE and PP samples have been investigated thoroughly. Compression tests on amorphous and cold crystallised PET showed that the strain hardening remained unchanged, despite the de...

Motivated by relaxation in the calculus of variations, this paper addresses convex but not necessarily strictly convex minimization problems. A class of energy functionals is described for which any stress field σ in L(Ω) with div σ in W 1,p ′ (Ω) (from Euler Lagrange equations and smooth lower order terms) belongs to W 1,q loc (Ω). Applications include the scalar double-well potential, an opti...

Due to aggressive scaling down, multiple-node-upset hardened design has become a major concern regarding radiation hardening. The proposed latch overcomes the architecture and performance limitations of state-of-the-art double-node-upset (DNU)-resilient latches. A novel stacked element is developed with multiple thresholds, regular architecture, increased number single-event upset (SEU)-insensi...

We investigate the cyclic behavior of laminate microstructures in finite-strain crystal plasticity and the resulting stress-strain response, based on a variational, incremental description of the microstructure evolution. The nonconvex free energy density in multiplicative singleand multi-slip plasticity gives rise to the formation of fine-scale deformation structures, experimentally observed a...

spring back is responsible for inaccuracy of press formed sheet product. therefore, prediction of spring back is important for precise forming of stampings. to predict the amount of spring back many successful attempts have been made for simple cases such as single curved and u or v shape sheet metals. however, for more complex shapes containing double curves or double variable curved surfaces ...

A constitutive multi-laminate based elastic-plastic model developed to be capable of accounting induced anisotropic behavior of granular material such as sand. The fabric feature or grain orientation characteristic effects through medium are considered in a rational way under any complex stress path, including cyclic loading. The salient feature of the developed model is a non-associative on pl...