Residual strength prediction of damaged composite bonded and bonded-riveted aircraft panels with integral boundary equations method

摘要

In recent time transition to aircraft designing based on the fail-safe principle and increasing use of composite materials in different areas of engineering have led to necessity to develop efficient methods of solving the local strength problems for aircraft structures with cracks. For composite materials the usual mechanical attachments don't provide the required strength. Therefore, the development of computational methods for stress-strain state and residual strength of the bonded and bonded-riveted damaged aircraft structural elements made of metal alloys and composite materials is an actual problem. The essence of the research is in presentation of solutions of correspondent static problems in terms of potentials with unknown intensities. The solution of the task for stiffened composite panels is received by reducing boundary conditions on cutout or crack contours and displacement compatibility conditions at attachment points, lines of the stiffening elements to a system of boundary integral equations. An algorithm for numerical solution of the received equations is offered as well as its realization in the form of computer program. Analytical results on residual static strength of aluminum and composite panels containing fatigue cracks are presented, and load-carrying capability of these airframe units is evaluated. Analytical results on residual static strength of aluminum and composite panels containing fatigue cracks are presented, and load-carrying capability of these airframe units is evaluated.