ROBUST DESIGN OPTIMISATION OF ADVANCE HYBRID (FIBERMETAL) COMPOSITE STRUCTURES

D. S. LEE; C. MORILLO; S. OLLER; G. BUGEDA; E. OÑATE

Conferencia; Mechanics of Nano, Micro and Macro Composite Structures; 2012

 The paper develops a methodology for design optimisation of laminated advanced Hybrid Composite Structures (HCSs). HCSs are consisting of alternating layers of Fiber-Reinforced Polymer (FRP) and metal sheets. These hybrid materials can be used in the fields of aerospace and marine due to superior mechanical properties over the conventional FRP laminates and the high-strength monolithic metal alloys. Mechanical properties and responses for off-design conditions of HCSs can be improved using an innovativemethodology coupling Multi-Objective Genetic Algorithm (MOGA) and robust design method.The concept of robust design approach ensures that a structure will be tolerant to unexpected loading and operating conditions. In this paper, two applications are considered; the first application is to maximise the stiffness of the hybrid composite while minimising its total weight through a multi-objective design optimisation. The second application considers a Robust Multi-objective Design Optimisation (RMDO) to minimise total weight of hybrid composite structure and to minimise both the Normalised Mean Displacement (NMD) and the Standard Deviations of the Displacement (SDD) considering critical load cases including bending, shear, and torsion load cases. For the optimisation process, a distributed/parallel Multi-Objective Genetic Algorithm (MOGA) in Robust Multi-objective Optimisation Platform (RMOP) developed at CIMNE is used and it is coupled to a Finite Element Analysis (FEA) based composite structure analysis tool named Compack to find the optimal combination of laminates sequences for HCSs. Numerical results show the advantages in mechanical properties of advance HCS over the Metal Structures (MSs), and also the use of RMDO methodology to obtain higher characteristics of HCS in terms of mechanical properties and its stability at the variability of load cases.