Variable-amplitude oscillatory shear tests are emerging as powerful tools to investigate and quantify the nonlinear rheology of amorphous solids, complex fluids, and biological materials. Quite a few recent experimental and atomistic simulation studies demonstrated that at low shear amplitudes, an amorphous solid settles into an amplitude- and initial-conditions-dependent dissipative limit cycl...

Plant cell morphogenesis depends critically on two processes: the deposition of new wall material at the cell surface and the mechanical deformation of this material by the stresses resulting from the cell's turgor pressure. We developed a model of plant cell morphogenesis that is a first attempt at integrating these two processes. The model is based on the theories of thin shells and anisotrop...

In this paper we develop a finite deformation micromechanical framework for modeling rate-dependent failure in unidirectional composites under off-axis loading. The model performance is compared with original experiments on thermoplastic carbon/PEEK tested at different strain-rates and angles. To achieve quantitative agreement the experiments, microcrack initiation criterion based local stress ...

Research on the Small Punch Test (SPT) has been mainly focused metallic alloys, with limited investigations in polymeric materials. The miniature size of SPT eases and motivates its use biomedical applications, like mechanical characterization surgical implants made different polymers. It is noted that aim these publications was properties inherent to tensile test (yield strength, ultimate Youn...

A new technique, High-Temperature Scanning Indentation (HTSI), is proposed to investigate metallurgical evolution occurring during anisothermal heat treatments. This technique based on the use of high-speed nanohardness measurements carried out linear thermal ramping system with appropriate settings. specific loading procedure, a quarter sinus function, creep segment and three-step unloading me...

In the present work, large deformation rate-dependent constitutive behavior of isotactic polypropylene is studied via an experimentally validated macroscale model. To analyze nonlinear response material, mechanical tests are conducted at room temperature and a phenomenological model proposed to describe viscoplastic yielding damage semicrystalline polymer. The based on finite elastic-viscoplast...

Rocket engine thrust chambers withstand very high temperatures and thermal gradients during service that induce multiple damaging phenomena such as plasticity, low-cycle-fatigue (LCF) creep. Numerical models can be used the design of these mechanical components in order to simulate main processes, accounting for complex material behavior due non-linear hardening viscoplasticity. This work repre...

Abstract This work presents a viscoplastic localization criterion to detect quasi‐instantaneous (i.e., load‐induced) and delayed (creep‐induced) strain in rate‐dependent solids. The study is based on the theory of controllability description mechanical response. Analytical precursors unstable states are defined through systems ordinary differential equations (OEDs). use proposed criteria illust...