Application of PATCHES-III to the Three-Dimensional Response of Laminated Composite Structures,
MCDONNELL DOUGLAS ASTRONAUTICS CO HUNTINGTON BEACH CALIF
Pagination or Media Count:
A recently developed program for the stress analysis of general solids of composite material is applied in this study to a sandwich panel impact problem and a partially cracked laminate problem. Objectives of the study are 1 to determine the load distribution, the stresses and the deformations in individual plies of these composite laminates and 2 to demonstrate the modeling capabilities and limitations of the PATCHES-III program. Preparatory to the analyses, the program was updated to automate the superposition of symmetry - asymmetry subcases for more efficient modeling. The present application of the PATCHES-III system to laminated composites was successful in predicting the three-dimensional response of individual plies at very reasonable modeling and computational costs. Engineering checks of the overall response with hand calculations using beam and plate models were in good agreement for both the sandwich panel and the partially cracked laminate. A modeling error in the boundary conditions for the latter problem introduced fictitious normal forces for the asymmetry subcase. These forces were evaluated when the error was discovered and found to be small, on the order of 0.015 lbs. maximum, and judged not to have a significant effect on the redistribution of load around the crack. The constraint force calculations were made possible by a postprocessor data file system developed as one of the objectives of the effort. The Experience gained from the present study also indicates the need for improvement in certain areas.
- Computer Programming and Software
- Structural Engineering and Building Technology