Poly lactic acid (PLA) is widely used for the manufacture of biodegradable stents (BDSs). It was observed and investigated that tensile loads can significantly affect the degradation rate of PLA in our previous study. Additionally, non-uniform degradation can arise from complicated stress distributions in implanted stents under long-term and pulsatile tensile loading. The objective of this work...

This numerical investigation of an advanced Gurson–Tvergaard–Needleman(GTN) model is an extension of the original work of Ben Bettaieb et al. (2011). The model hasbeen implemented as a user-defined material model subroutine (VUMAT) in the Abaqus/explicitFE code. The current damage model extends the previous version by integrating the threedamage mechanisms: nucleation, growth an...

The probabilistic analysis takes into consideration an effect of scatter in elastic and strength properties of composite beam, and velocity of impactor. The damage model is implemented in the FE (finite element) code by a VUMAT (user-defined subroutine). The inter ply failure is modeled using cohesive surfaces between the plies. Dynamic response is obtained using explicit time domain integratio...

The paper briefly summarizes the theoretical derivation of the objective stress rates that are work-conjugate to various finite strain tensors, and then briefly reviews several practical examples demonstrating large errors that can be used by energy inconsistent stress rates. It is concluded that the software makers should switch to the Truesdell objective stress rate, which is work-conjugate t...

Carbon fiber reinforced thermoplastic polymer (CFRTP) laminates can be used in packaging electronics components to reduce weight and shield external disturbance. The CFRTP structures operation are inevitably suffer dynamic loading conditions such as falling rocks, tools impacts. In this study, a strain rate dependent material model for accurately evaluating the response of with different stacki...

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...

In the present work, a set of physically-based failure criteria are applied to cross-ply Non-Crimp Fabric (NCF) composite. The proposed account for stitch reinforcement and induced in- out-of-plane fibre misalignment. A distinction between matrix failures in tension compression is introduced, while in-plane shear non-linear response directly incorporated model as well. constitutive associated w...

The present paper presents an investigation and analysis study of the effect head shapes impactor on damages observed during low-velocity impact T700/Epoxy composite laminate. Two types impactors were investigated: hemispherical flat-face. A new criterion based LARC05 damage model was linked as a LARC_VUMAT subroutine to simulate explore effects form shape through three-dimensional finite eleme...

In this paper, we have modified the stress integration scheme proposed by Choi and Yoon [1]; which is based on numerical approximation of yield function gradients, to implement in finite element code ABAQUS three elastic isotropic, plastic anisotropic constitutive models with yielding described Yld2004-18p [2], CPB06ex2 [3] Yld2011-27p [4] criteria, respectively. We developed both VUMAT UMAT su...

Understanding the effect of thermomechanical loads during finish cutting processes, in our case hard milling, on surface integrity workpiece is crucial for creation defined quality characteristics high-performance components. Compared to computationally generated modifications by simulation, measurement-based determination material can only be carried out selectively and a point-by-point basis....