An effective numerical approach is proposed for structural damage analysis, especially for structures which may be damaged at multiple locations to different extents. The structural damage state is represented by defining a set of field-variable functions, and the degradation of material properties is described. Then, through customization of the commercial finite element software ABAQUS/Standard, the damage state is directly assigned to the integration points of elements, thereby avoiding modification of the finite element model. Afterwards, the damaged structures by ABAQUS/Standard is conducted numerically. Finally, this approach is verified by simulating the growth of delamination for a pre-delaminated composite plate and a composite plate under impact loading, respectively.
In order to effectively describe the progressively intralaminar and interlam- inar damage for composite laminates, a three dimensional progressive damage model for composite laminates to be used for low-velocity impact is presented. Being applied to three-dimensional （3D） solid elements and cohesive elements, the nonlinear damage model can be used to analyze the dynamic performance of composite structure and its failure be- havior. For the intralaminar damage, as a function of the energy release rate, the damage model in an exponential function can describe progressive development of the damage. For the interlaminar damage, the damage evolution is described by the framework of the continuum mechanics through cohesive elements. Coding the user subroutine VUMAT of the finite element software ABAQUS/Explicit, the model is applied to an example, i.e., carbon fiber reinforced epoxy composite laminates under low-velocity impact. It is shown that the prediction of damage and deformation agrees well with the experimental results.
