Zamani D, Racionero Sánchez-Majano A, Pagani A
MUL 2 Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy.
Department of Aerospace Engineering, Universidad Carlos III de Madrid, Av. de la Universidad 30, 28911 Leganés-Madrid, Spain.
Struct Multidiscipl Optim. 2025;68(6):107. doi: 10.1007/s00158-025-04043-6. Epub 2025 Jun 14.
Automated fiber placement (AFP) has made it possible to vary the steering angle along curvilinear fiber paths, thus improving mechanical performance compared to traditional composite materials. Variable-angle tow (VAT) or variable-stiffness composites (VSC) have been developed to enhance structural performance through material optimization and effective load-bearing configurations. These advanced materials contribute to achieving optimal performance while reducing the weight of aircraft and aerospace structures. However, defects such as gaps and overlaps may arise during the manufacturing process. Whereas the latter increases local thickness, the former causes resin-rich areas within each lamina. The mass and structural optimization of this kind of structure is challenging as it combines discrete and continuous design variables, namely the number of layers and the fiber path parameters, where the latter influence the presence of defects within the laminate. To tackle this optimization problem, this work proposes a mixed-integer strategy specifically designed to select the least-weight design of a VAT laminate while also fulfilling requirements on the first natural frequency and buckling load while accounting for the manufacturing signature of the AFP process. This study combines the Carrera unified formulation (CUF) and the defect layer method (DLM) to model the VAT laminates and incorporating the fabrication defects. The research has two main aims: (i) to determine the minimum number of layers required to satisfy the fundamental frequency and buckling constraints, considering the manufacturing signature, and (ii) to investigate the influence of the selected structural theory on the optimal design solutions.
自动铺丝（AFP）使得沿曲线纤维路径改变转向角成为可能，因此与传统复合材料相比，其机械性能得到了提升。变角度丝束（VAT）或变刚度复合材料（VSC）已被开发出来，通过材料优化和有效的承载配置来提高结构性能。这些先进材料有助于在减轻飞机和航空航天结构重量的同时实现最佳性能。然而，在制造过程中可能会出现诸如间隙和重叠等缺陷。后者会增加局部厚度，而前者会在每个层板内形成富树脂区域。这种结构的质量和结构优化具有挑战性，因为它结合了离散和连续的设计变量，即层数和纤维路径参数，其中后者会影响层压板内缺陷的存在。为了解决这个优化问题，本文提出了一种混合整数策略，专门设计用于选择VAT层压板的最轻重量设计，同时在考虑AFP工艺制造特征的情况下满足对一阶固有频率和屈曲载荷的要求。本研究结合了卡雷拉统一公式（CUF）和缺陷层方法（DLM）来对VAT层压板进行建模并纳入制造缺陷。该研究有两个主要目标：（i）考虑制造特征，确定满足基频和屈曲约束所需的最少层数；（ii）研究所选结构理论对最优设计方案的影响。
