Fiber Path Optimization of Symmetric Laminates with Cutouts for Thermal Buckling

Abstract

Automated fiber placement technology has pushed for the need to explore nonconventional fiber paths in laminated composites. This paper investigates optimal spatially varying fiber paths in a symmetric linear orthotropic laminate, which could increase the critical buckling temperature under uniform applied thermal loads. The key idea here is to achieve gains in buckling performance yet focus on manufacturability of the obtained optimal fiber path. The subject of this study is a four-layer symmetric orthotropic laminated plate, with a central circular cutout that is clamped on all the edges. A novel finite element algorithm is proposed, which imposes a condition on the definition of discrete fiber angles within each element. The main objectives of the proposed finite element approach are to maintain continuity of the fiber paths and to use a computationally efficient model by reducing the number of optimization variables.