Process-Induced Residual Thermal Stresses in Advanced Fiber-Reinforced Composite Laminates

Abstract

A study of process-induced stresses in advanced fiber-reinforced composite laminates is presented. An analysis of the residual thermal stresses is conducted on the basis of laminate thermoelasticity theory in conjunction with a quasi-three-dimensional finite element method. Formulation of the numerical method is briefly outlined in the paper. To illustrate the fundamental nature of the problem, numerical examples for a quasi-isotropic [0 deg/90 deg/ ± 45 deg]s graphite-epoxy composite system are presented. Complex three-dimensional stress states of significant magnitude are reported. Emphasis is placed on the interlaminar stress distributions along ply interfaces. Effects of laminate stacking sequence on the residual thermal stresses are examined in detail. Implications of the results on deformation and failure of composite laminates are discussed.

The origins of residual stress and its evaluation in composite materials

“…• Elastic model: Early process models used elastic models to describe the behavior of the material (e.g., Harper & Weitsman, 1981;Loos & Springer, 1983;Nelson & Cairns, 1989;Stango & Wang, 1984). In these models, the stress calculation is based on the final relaxed modulus of the material: Although this type of model might provide some insights into the behavior of the material and development of residual stresses, it cannot capture the complexity of the problem or give quantitatively good results.…”

Experimental and numerical study of distortion in flat, L‐shaped, and U‐shaped carbon fiber–epoxy composite parts

“…To avoid this issue, prediction of the dimensional changes has been of interest to many investigators who tried to address the issue by developing simple equations [53,54] as well as analytical and numerical models [6,12,25,26,30,32,[55][56][57][58][59][60]. The model that incorporates more phenomena can provide more accurate predictions.…”

Curing-Induced Distortion Mechanism in Adhesive Bonding of Aluminum AA6061-T6 and Steels

“…Based on their studies, the residual stress in adhesive-bonded joints with dissimilar adherends is closely related with the glass transition temperature or the curing temperature of the adhesives. Currently, modeling such as finite element method [15][16][17][18][19] has been applied to analyze the thermal stress in adhesive-bonded joints. However, to the best of our knowledge, little information is available concerning the distortion mechanism in rivet bonding or weld-bonding of the dissimilar materials, thereby limiting the implementation of adhesive bonding in multimaterial vehicle manufacturing.…”