Research On Aircraft-Door-Based LVI Damage Model And Repair Tolerance Assessment Technique

With the tremendous increase in computer technique over the last decades,numerical analysis has been achieving more and more success in composite structure design and LVI of composites has become a focus among researchers.Because of the difficulty in establishing material properties,failure criterion and numerical techniques,the modelling of three-dimensional impact damage and its growth is still challenge which is why in industries,costly full-scale tests are required to improve and verify composite design.In this paper,Chang-Chang failure criterion was introduced to modify the traditional Hashin failure criterion,programmed into a user subroutine VUMAT with FORTRAN.To verify the failure criterion with test data,the VUMAT was called in ABAQUS for composite laminate with cohesive element predicting delamination.Consequently,Composite strengthened skin of airtight aircraft door 3D FE model was built with above verified simulating techniques to analyze the impact damage under the influence of mesh density,impact energy and impact location.And eventually repair tolerance analysis of composite airtight aircraft door was implemented based on safety and economy.