The viscoplastic behavior of a carbon-fiber/polymer matrix composite was investigated through two different modeling efforts. The first model is phenomenological in nature and utilizes the tensile and stress relaxation experiments to predict the creep strain. The phenomenological model was constructed based on the overstress viscoplastic model. In the second model, the composite viscoplastic be...

The fracture of viscoplastic materials is a complex process due to its time-dependent and plastic responses. Numerical simulation for fractures plays significant role in crack prediction failure analysis. In recent years, the phase field model has become competitive approach predict growth been extended inelastic materials, such as elasto-plastic, viscoelastic etc. However, contribution energy ...

A physically based elasto-visco-plastic constitutive model is presented and compared to experimental results for a DD14 mild steel. The model requires significantly fewer material parameters compared to other visco-plasticity models from the literature while exhibiting very good accuracy. Accordingly, the parameter identification is simple and intuitive, requiring a relatively small set of expe...

Local damage models are known to produce pathological mesh dependence in finite element simulations. The solution is to either use a regularization technique or to adopt a non-local damage model. Viscoplasticity is one technique which can regularize the mesh dependence of local damage model by incorporating a physical phenomenon in the constitutive model i.e. rate effects. A detailed numerical ...

1.Abstract A continuum-based design sensitivity analysis (DSA) applied to the thickness design of the anisotropic elasto-plastic shell structures is developed. Since main interest lies in developing path-following algorithms for solving sensitivity problems of elasto-plasticity, such an incremental or a step-by-step formalism will be employed to implementation into the structural analysis progr...

Electronic power modules devices are paramount components in the aeronautical, automotive and military applications. The solder layers are the most critical parts of the module and are usually subjected in their whole life to complex loading conditions. To improve the design task, realistic thermoelastoviscoplastic and lifetime prediction models which can describe efficiently the deformation-da...

A thermomechanical fatigue life prediction model based on the theory of damage mechanics is presented. The damage evolution, corresponding to the material degradation under cyclic thermomechanical loading, is quantified thermodynamic framework. The damage, as an internal state variable, is coupled with unified viscoplastic constitutive model to characterize the response of solder alloys. The da...