Matrix cracking evolution in open-hole laminates subjected to thermo-mechanical loads

In this work, a constitutive model is developed and used to predict matrix cracking and fiber damage evolution in all the plies of symmetric laminates when both mechanic and thermal loads are applied. A model previously developed is modified to take into account the thermal stresses that appear in each ply when the temperature is reduced below the Stress Free Temperature. Data of matrix damage initiation and evolution due to thermomechanical loads for four materials and six laminate lay-ups taken from the scientific literature are used to validate the model. A good correlation between the predictions and the experimental results is found. The model is used to analyze the thermomechanical damage in laminates containing a centered hole subjected to in-plane tensile loads. It is observed that the thermal load alone does not produce a stress concentration around the hole but the thermal residual stress accelerates damage accumulation during mechanical load. (C) 2017 Elsevier Ltd. All rights reserved.The authors are indebted for the financial support of this work to the Ministry of Economy and Finance of Spain (project DPI2013-42240-R)

Effect of adhesive thickness and overlap on the behaviour of composite single-lap joints

The effect of adhesive thickness and adherent overlap on behavior of composite single-lap joints (SLJ) under tensile load is studied by using a 3D finite-element model. A bilinear Cohesive Zone Model (CZM) law is used to represent the adhesive behavior and its parameters are determined as a function of adhesive thickness by carrying out Double Cantilever Beam and End-Notched Flexure tests. The performance of SLJ is defined by peak load, maximum shear, and peel stresses. For the range of adhesive thicknesses considered, both maximum shear and peel stresses decrease with increasing adhesive thickness, while they increase with increasing overlap length