design and weight optimization of pin loaded composite plates

in design and optimization process of laminated composite structures, the number of layers, layer angles, stacking sequence, material types and etc should be specified. each of aforesaid parameters can be applied as a design variable. in this paper the target is to minimize the weight of laminated composite pin loaded structures. the laminated composite structures are designed based on the load of pin. pin mounting in laminated composite plates causes stress concentration around the hole of pin. in this research the programming facility of fe software (ansys) is used for design and optimization of laminated plate. constrains of minimization problem is based on tsai-wu criterion. the pin loaded plate is divided to two regions: the around of hole and far away from hole. the optimization process is solved concurrently and interactively for two regions. the selected stacking sequences are the quasi isotropic, cross ply and angel ply. the target is to obtain a configuration with accessible number of plies. for this reasom the branch and bound method was used. the obtained results show that the quasi isotropic plate is stronger than cross ply plate and cross ply plate is stronger than angle ply plate. but this order is reversed in a special load. in the other words the cross ply plate is being stronger than quasi isotropic plate in this case. in this paper also effect of geometric parameters over the strength of pin loaded plates are investigated .