Reliability-based robust design optimization of laminated composite structures

Abstract

The probability approach is the most popular way to quantify uncertain parameters and perform reliability analysis. The problems of structural optimization and robust design for laminated composite structures with reliability constraints are addressed in this paper. A new methodology to determine the optimal r obust configuration of laminated composite structures with reliability constraints is proposed. In the proposed method, the criterion of Tsai-Wu is adopt to determine the failure of composite materials, the reliability analysis is performed by using Monte Carlo simulation, and the multi-objective optimization involved in the classical reliability-based robust design can be transformed into the single-objective optimization by using two-level optimization algorithm. A numerical example is given, it is shown that the proposed method is e ffective and feasible. I ntroduction Aeronautic applications of composite materials have increased due to their excellent specific stiffness, low weight, and designability. The number of layers, fiber orientation angles, thickness of each layer, and the sequence of layers can be changed to optimize laminated composite structures. Lots of unavoidable uncertainties exist when laminated composite structures are generally used under special and severe circumstances. Thus it is necessary to take the uncertainties into consideration when designing these structures. Consequently, reliability of optimized designs becomes especially important in the field of laminated composite structures (1). Reliability-based design optimization (RBDO) of composite structures is currently a very important area of research(2-5). I n the actual production, the design parameters may appear error to influence the objective function. In traditional optimization, this influence is not considered, and robust design methods can solve this problem. R obust design optimization of composite structures is another emerging area of research that is thought of as an alternative design to RBDO. Robust design is to improve product quality by minimizing the uncertainty effects in structural response. Robust design optimization of composite structures under probabilistic constraints is a very important due to uncertainties associated with physical properties of fiber-reinforced composites.