THERMAL-EXPANSION COEFFICIENTS OF CRACKED LAMINATES

Effective thermal expansion coefficients of cross-ply laminates containing many intralaminar ply cracks are evaluated as functions of ply thermomechanical properties and crack density. The method employed is applicable to any cracked laminate if internal stress fields due to mechanical loads are known. Results obtained demonstrate strong reduction of expansion coefficients due to cracks. It is shown that because of opening of cracks by tension and closing by compression the laminate has several different expansion coefficients, each valid for a different load-temperature combination.