Failure Analysis of a Composite Laminate in HyperWorks through “Ply Elimination” Procedure

The failure analysis of a composite laminate can be carried out through different first-ply failure criteria. traditional criteria, such as Tsai-Wu criterion, allow the evaluation of the Margin of Safety (MS) for each ply, but generally they are not considered to be reliable enough. In fact, from engineering experience, it has been demonstrated that a negative MS does not necessarily imply a catastrophic failure of the structure. In reality a stress redistribution arises in the structure as a result of stiffness modifications caused by local damage, thus permitting the structure ultimate resistance to the external loads.

The well known Ply Elimination Procedure allows in-depth investigations into the resistance capabilities of composite laminates. The procedure is iterative and based on the local degradation of the elastic properties of the areas with negative MS and the re-analysis of the degraded structure through the failure criterion.

The subroutine HM_PE.tcl, programmed in Tcl-Language, has been developed as an accessory tool to be run in HyperWorks for an automatic application of the ply elimination loop to the finite element model of a composite laminate.

The Author

Agusta Westland, Ing. Daniele Di Sanzo

<< Back