Finite element modeling of effective properties of nanoporous thermoelastic composites with surface effects

This investigation concerns to the determination of the material properties of nanoscale thermoelastic composites of an arbitrary anisotropy class with stochastically distributed porosity. In order to take into account nanoscale level at the borders between material and pores, the GurtinMurdoch model of surface stresses and the highly conduct- ing model are used. Finite element package ANSYS was used to simulate representative volume and to calculate the effective material properties. This approach is based on the theory of effective moduli of composite mechanics, modeling of representative volumes and the finite element method. Here, the contact boundaries between material and pores were covered by the surface membrane elastic and thermal shell elements in order to take the surface effects into account

Finite element modeling of effective properties of nanoporous thermoelastic composites with surface effects

This investigation concerns to the determination of the material properties of nanoscale thermoelastic composites of an arbitrary anisotropy class with stochastically distributed porosity. In order to take into account nanoscale level at the borders between material and pores, the GurtinMurdoch model of surface stresses and the highly conduct- ing model are used. Finite element package ANSYS was used to simulate representative volume and to calculate the effective material properties. This approach is based on the theory of effective moduli of composite mechanics, modeling of representative volumes and the finite element method. Here, the contact boundaries between material and pores were covered by the surface membrane elastic and thermal shell elements in order to take the surface effects into account

Comparative Study on Progressive Damage Models for Composites

The evolution of damage in laminated fiber reinforced composites is a complex phenomenon, which involves interaction of different modes of failure like fiber breakage, matrix cracking, fiber-matrix debonding and delamination. In the present work the effect of fiber volume fraction and different damage mechanisms such as fiber breakage, fiber-matrix debond and matrix cracks on the effective properties of unidirectional fiber-reinforced composites is predicted based on a micromechanical analysis. The material properties are calculated using a three-dimensional micromechanical representative volume element (RVE). A finite element based progressive damage model is developed to predict failure behavior of a laminate in respective load-constraint conditions. The proposed model also helps to determine where and how failure occurs first and how the damage evolves. Hashin’s and Puck’s failure models are used for laminated composite plates of various stacking sequences and their respective numerical results are compared. The influences of the failure criteria and material degradation model are studied through a numerical analysis. The case studies considered vary from a unidirectional laminate with a hole, laminates with single bolt lap joint