Composites

ABAQUS Composite Failure and Fracture

Prediction Software Available

Last spring, ABAQUS announced it would offer new capability for its advanced finite element analysis software suite with an add-on called VCCT for ABAQUS. The add-on is based on specific Virtual Crack Closure Technique (VCCT) software originally developed by Boeing and refined by ABAQUS to provide fracture and failure prediction in laminated composites (AM, August 2004). ABAQUS now reports the implementation and commercial availability of the VCCT for ABAQUS add-on, integrated into the ABAQUS/Standard Version 6.5 analysis environment.

By accurately simulating delamination in composite structures, the VCCT for ABAQUS add-on software can help identify the overall load at which a crack initiates and predict the behavior of the structure as the crack length increases. Equally important, VCCT for ABAQUS analyzes the stability and load-carrying capability of the composite structure after failure, which is vital for ensuring durability and damage tolerance in aerospace components. Dale Berry, manager of engineering applications for ABAQUS, reports that VCCT can be calculated at run time during an ABAQUS simulation rather than as a postprocessing routine and does not require definition of interface elements at the bond line since it is based on the existing surface-based debond capability in ABAQUS/Standard.�No remeshing, reanalysis, or standalone postprocessing is necessary, unlike traditional VCCT.

Further, both stable and unstable crack growth problems can be solved using the existing stabilization methods within ABAQUS as well as some additional tools available within VCCT for ABAQUS. Multiple cracks in a structure with each crack progressing at its own rate can also be analyzed; Berry notes that multiple cracks can interact with each other during the solution. Finally, full graphical plotting of crack growth patterns and other VCCT output variables is completely supported by ABAQUS/Viewer.

VCCT for ABAQUS, while licensed separately from other ABAQUS products, utilizes the well-regarded nonlinear and composites analysis capability of ABAQUS. "When a structural component cracks, does it fail immediately or does it exhibit residual strength and over what time period? This is what VCCT for ABAQUS can help analyze, by extending the virtual testing of composite structures," Berry concluded.

- By Vicki P. McConnell, Technology Editor