JEC COMPOSITES MAGAZINE - Issue #76 - October/November 2012 - 86

software

Micromechanical software enables efficient multiphysics composites modelling
The complexity of engineering systems at the microlevel greatly complicates the analysis of macroscopic behaviour. Direct analysis is computationally intensive and unrealistic. SwiftComp Micromechanics is capable of predicting the effective properties of composites and local fields within the microstructure.

allan Wood, President & Ceo, analysWiFt WenBin yu, Cto, analysWiFt assoCiate ProFessor oF MeCHaniCal and aerosPaCe engineering at utaH state uniVersity

hile composite materials have proved in many ways superior to conventional materials, the increasing complexity of engineering systems at the microlevel greatly complicates the analysis of macroscopic behaviour. This analysis, however, is indispensable for a rational design of these systems. While direct analysis is possible, it is computationally intensive and unrealistic. A new micromechanics code developed at Utah State University addresses these challenging issues. SwiftComp Micromechanics, also known as VAMUCH (Variational Asymptotic Method for Unit Cell Homogenization), is a recently developed micromechanics theory capable of predicting not only the effective properties of composites and other heterogeneous materials, but also the local fields within the microstructure. Utilizing the powerful variational asymptotic method (VAM), SwiftComp is the first truly general-purpose micromechanics software program for composites.

implementing the various micromechanics theories based on VAM to simplify originally heterogeneous materials using effective homogeneous materials, the properties of which are obtained through a micromechanical analysis of a microstructure, commonly called UC (unit cell) or RVE (representative volume element), representative of the heterogeneous material (Figure 1). SwiftComp takes a finite element mesh of the UC including all the details of geometry and material as inputs to calculate the effective properties. These properties are needed for the macroscopic structural analysis to predict the global behaviour. The 3D point-wise local field distribution within the microstructure can also be recovered based on the global behaviour of the macroscopic structural analysis. In addition to providing a general framework for modelling heterogeneous materials,

SwiftComp has several unique features in both its theory and application in comparison to other micromechanics approaches. For instance, taking advantage of the smallness of the microstructure of heterogeneous materials, it formulates a variational statement of the unit cell through an asymptotic analysis of the energy functional by invoking only two very basic assumptions of micromechanics. Other convenient assumptions commonly used in the literature are avoided. Although it is easy to distinguish SwiftComp from other analytical micromechanics approaches, it is often confused as one of the FEA-based micromechanics approaches because the equations of the VAMUCH theory are solved using the finite element technique. FEA-based micromechanics approaches carry out a conventional finite element analysis of an RVE (or UC) with specially designed boundary conditions under specifically designed loads. Although SwiftComp has the same versatile modelling capability as FEA-based approaches, it is dramatically different both in its theory and application.

Micromechanics approaches
SwiftComp Micromechanics (VAMUCH), now in version 3.0, is a software program
Fig. 1: Micromechanics homogenization

Theoretical differences
Although there are significant theoretical differences between SwiftComp and other

86 jec composites magazine / No76 October - November 2012

JEC COMPOSITES MAGAZINE - Issue #76 - October/November 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #76 - October/November 2012