EFFECT OF THERMAL RESIDUAL STRESSES ON BUCKLING AND POST-BUCKLING PROPERTIES OF LAMINATED COMPOSITES PERIMETRALLY REINFORCED

Abstract

SEVERAL MECHANICAL PROPERTIES CAN BE AFFECTED BY THE OCCURRENCE OF CURING RESIDUAL STRESSES AND THEIR EFFECTS ARE MORE PRONOUNCED IN LAM-INATED COMPOSITES. THE EFFECT OF THE THERMAL RESIDUAL STRESSES ON THE BUCKLING AND POST BUCKLING PROPERTIES OF LAMINATED COMPOSITES PERIME-TRALLY REINFORCED IS EXPERIMENTALLY CHARACTERIZED IN THIS STUDY. CAR-BON/EPOXY LAMINATES WERE PREPARED USING TWO DIFFERENT TECHNIQUES. ONE GROUP OF LAMINATES WAS PREPARED BY CO-CURING THE REINFORCEMENT AT 177 °C. THE SECOND GROUP OF LAMINATES WAS PREPARED BY SECONDARY BONDING OF THE REINFORCEMENT TO THE LAMINATE AT ROOM TEMPERATURE (22°C). A TOPOGRAMMETRY EQUIPMENT WAS UTILIZED TO DETERMINATE THE BUCKLING AND POST-BUCKLING PROPERTIES OF THESE TWO GROUPS OF LAMI-NATES. A NUMERICAL MODEL WAS ACHIEVED USING A COMMERCIAL SOFTWARE FOR COMPARISON WITH THE EXPERIMENTAL RESULTS. A SUITABLE ACCURACY WAS OBSERVED WHEN COMPARING EXPERIMENTAL AND NUMERICAL RESULTS. THE CO-CURED LAMINATES DEVELOPED CONSIDERABLY HIGHER CRITICAL LOAD OF BUCKLING VALUES THAN THOSE OBTAINED FOR LAMINATES PRODUCED WITH SECONDARY BONDING AT ROOM TEMPERATURE. THE EXPERIMENTAL AND NUMERICAL RESULTS OF THIS STUDY DEMONSTRATE THE IMPORTANCE OF CURING INDUCED THERMAL RESIDUAL STRESSES ON THE MECHANICAL BEHAVIOR OF LAMINATES COMPOSITES.