Structural Analysis and Optimization of Layered Composite Structures: Numerical and Experimental Investigations

Katarina Maksimović, Stevan Maksimović

The investigation in this work is focused on developing reliable computation procedure to analyze initial failure load for pin-loaded holes at the layered composite structures. Finite element method (FEM) is used to determine stress distribution around the fastener hole. The model takes into account contact at the pin-hole interface. Combining Chang-Scott-Springer characteristic curve model and Tsai-Wu initial failure criterion are used to determine joint failure. Special attention in this work is on pin-load distributions and its effect on load level of failure and its location. Here is contact finite element pin/lug model analyzed. The influence of stacking sequences of layered CFC composites type NCHR 914/132/300, containing pin-loaded holes is investigated, too. The computation results are compared with own and available experimental results. An efficient optimization method is presented for minimum weight design of the large-scale structural system such as aircraft structural systems. The efficiency of method is based on application of the two-level approach in structural optimization structural systems. Optimization method presented here is based on combining optimality criterion (OC) and nonlinear mathematical programming (NMP) algorithms. Finite element analysis (FEA) are used to compute internal forces at the system level. The two-level optimization approach is applied to minimum-weight design of complex aircraft structures such as aircraft parashute composite beam subject to multiple constraints.