A review on optimization of composite structures Part I: Laminated composites

Effect of automated fiber placement (AFP) manufacturing signature on mechanical performance of composite structures

Predicting the low velocity impact damage of a quasi-isotropic laminate using EST

Maturity assessment of the laminate variable stiffness design process

Interlaminar to intralaminar mode I and II crack bifurcation due to aligned carbon nanotube reinforcement of aerospace-grade advanced composites

Robotic Automated Fiber Placement (RAFP) has revolutionized manufacturing of large aerostructures in recent years. From producing lower costing parts to reducing scrap, RAFP has also helped in manufacturing large parts with contours precisely, with repeatable production once the RAFP machine is programmed. RAFP manufacturing allows a designer to utilize curvilinear fiber paths specifically designed to optimize structural performance, for example, maximizing buckling loads, minimizing stress concentrations etc. At the same time, RAFP introduces unintended manufacturing imperfections. These, which can include overlaps and gaps, lead to thickness non-homogeneities in structural panels. In this paper, steered fiber paths for maximizing the buckling loads of RAFP panels while explicitly accounting for manufacturing imperfections is considered. A novel method to model fiber paths is introduced where each course of the lay-up can be explicitly modeled, including manufacturing artifacts of course width, admissible tow curvature, and control on unintended manufacturing deviations that can lead to gaps and overlaps. A machine learning based surrogate modeling technique in conjunction with Genetic Algorithm is used to derive the optimal solutions.

Optimal fiber paths for robotically manufactured composite structural panels

Effect of Automated Fiber Placement (AFP) Manufacturing Signature on Mechanical Performance

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.

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Avinkrishnan A. Vijayachandran

Papers

Effect of automated fiber placement (AFP) manufacturing signature on mechanical performance of composite structures

Optimal fiber paths for robotically manufactured composite structural panels

Effect of Automated Fiber Placement (AFP) Manufacturing Signature on Mechanical Performance

Fiber Path Optimization of Symmetric Laminates with Cutouts for Thermal Buckling

Particle Toughened Interfaces Enhance Mechanical Response of Composites