Analysis of the influence of the adhesive on process distortions of the co-bonded stringer foot specimens

Abstract : Process induced distortions prediction is a major issue for structural parts like self-reinforced panels. They may cause important displacements for parts of large dimension and compromise the quality of the assembly. Development of numerical process models is necessary to avoid the expensive and time-consuming trial-and-error approach. Various numerical models exist to predict those distortions. However, regarding co-bonded integrated structures, the influence of the adhesive film on final distortions is often ignored. The aim of this study is to simulate process induced distortions for co-bonded integrated structures and to understand the contribution of the adhesive film on those distortions. To do that, Finite Element Analysis (FEA) simulations are used. To be able to set up the FEA, thermal and mechanical properties are characterized for the epoxy-carbon fiber prepreg M21EV/IMA and the epoxy adhesive film FM300-M. Various models and parameters associated are determined and used to describe thermal and mechanical behaviour of both materials. Those models and properties are then employed to implement a FEA on ABAQUS using FORTRAN subroutines. The numerical model simulates process induced distortions during an autoclave cycle for co-bonded parts. Using this model, we aim to define stringer foot specimen geometry and lay-up to enable an experimental/numerical comparison.