| A finite element code was developed for calculating the stresses and strains in thick, curved, composite laminates subjected to an arbitrary, but consistent, combination of forces and displacements. The laminate may be arbitrarily curved in one plane but must have no curvature in the other two perpendicular planes. The accuracy of the stress analysis was evaluated by generating numerical results for three problems for which analytical solutions exist, and by comparing the numerical and the analytical results. In every case the agreement between the numerical and analytical results was excellent.; The analysis and the computer code were specialized to racetrack shaped composite straps loaded by pins in tension. A procedure was also established for estimating the failure loads of such straps, by utilizing the strains provided by the finite element method and the Tsai-Wu failure criteria.; Tests were performed to validate the strap stress analysis and failure model. Fourty-three straps were made of either T300/976, IM6/081, T1000/081 graphite-epoxy, K92/081 kevlar-epoxy, or S-2/081 glass-epoxy. The strains and failure loads of these straps were measured, and the data were compared to the calculated strains and failure loads. The calculated values agreed well with the data.; Lastly, the use of the computer code in the design of composite straps is discussed, and charts for estimating the failure loads of different types of straps are presented. |
