Session: CIE-03-01 - Computational Multiphysics

Paper Number: 90996

90996 - Elasto-Plasticity, Damage and Multiphysics Effects on the Behavior of Adhesive Step Lap Joints 

The potential effects of the presence of damage in the adhesive material as well as the combined environmental excitation in multi-material adhesive step-lap joints (ASLJ) often encountered in aircraft industries are frequently neglected. Historically, the design and qualification of ASLJs are based only within the scope of elasto-plastic response and failure. The present work describes the implementation and application of a computational framework enabling the performance evaluation of such joints under quasi-static loading conditions under the simultaneous presence of plasticity, damage and environmental stimulus. In particular, a ASLJ involving Ti-6Al-4V alloy adherents with a FM-300K adhesive is modeled under the proposed framework for various material responses and mutliphysics excitations. Sensitivity analysis with respect to damage-relevant material properties is first conducted to establish the variation limits of the macrosopic behavior of the ASLJ relative to elasto-plasticity. Then the heat transport effects representing the environmental condions, is added to the non-linear structural analysis.  It is shown that the assumption of assuming elasto-plastic failure as being the only behavior defining the failure of the adhesive, may not be an adequate assumption for designing and qualifying  ASLJs. Specifically, considering presence of plasticity, damage and environmental effects indicates that there are reasons to re-examine the design practices of such joints.

Presenting Author: John Michopoulos Naval Research Laboratory

Presenting Author Biography: Head of Computational Multiphysics Systems Lab at US-NRL

Authors:

John Michopoulos Naval Research Laboratory
Nicoleta Apetre US Naval Research Laboratory
Athanasios Iliopoulos US Naval Research Laboratory
John Steuben US Naval Research Laboratory