Foldable composite structures are bellows-like structures that can be stored in a flat state and deployed to a finite volume after folding. These composite structures are being increasingly demanded for numerous engineering applications including aerospace, aeronautics, robotics and medical. In this study, we report an original processing route for obtaining foldable composite laminates. These composite laminates were obtained by selectively curing pre-impregnated materials that were made of three layers of plain weave fabrics impregnated with an UV-curable epoxy-acrylate resin system. After selective curing, the composite laminates were made of rigid domains (cured zones) connected by flexible domains (uncured zones) that played the role of hinges upon folding. The selective curing of the photocurable resin system was performed using two different approaches. The first approach consisted in depositing UV-blocking masks designed numerically onto the surface of pre-impregnated materials before placing them inside the chamber of an UV-curing machine. The second one consisted in using a Digital Light Processing (DLP) 3D printing machine. The UV-curable epoxy acrylate resin exhibited fast curing kinetics characterized by a gelation time on the order of 1 s. Hence, both types of approaches enabled foldable composite laminates with very short time cycles (≈ 5 to 10 s) to be obtained. The as-obtained pre-impregnated sheets were folded into 3D composite structures and then irradiated with UV-light. This original fabrication method is versatile enough to provide a wide diversity of composite part geometries that are promising for many engineering applications. The observations of the microstructure of processed samples revealed that the reinforcement fabrics were rather well impregnated by the epoxy acrylate resin. These observations also tended to show that both types of approaches enabled a complete and efficient in-depth curing of the resin system.

可折叠复合结构是波纹管状结构，可以以平坦的状态存放，折叠后可以展开到有限的体积。包括航空航天、航空、机器人和医疗在内的众多工程应用对这些复合结构的需求越来越大。在这项研究中，我们报告了获得可折叠复合层压板的原始加工路线。这些复合层压板是通过选择性固化预浸渍材料获得的，该材料由三层平纹织物制成，浸渍有紫外线固化环氧丙烯酸树脂系统。选择性固化后，复合层压板由刚性域（固化区）和柔性域（未固化区）连接而成，柔性域在折叠时起到铰链的作用。光固化树脂体系的选择性固化使用两种不同的方法进行。第一种方法包括将数字设计的紫外线阻挡掩模沉积在预浸渍材料的表面上，然后将它们放入紫外线固化机的腔室内。第二个是使用数字光处理 (DLP) 3D 打印机。UV 固化环氧丙烯酸酯树脂表现出快速固化动力学，其特点是凝胶时间约为 1 秒。因此，这两种方法都能够获得具有非常短时间周期（≈ 5 到 10 秒）的可折叠复合层压板。将获得的预浸渍片折叠成 3D 复合结构，然后用紫外线照射。这种原始的制造方法具有足够的通用性，可以提供广泛多样的复合材料零件几何形状，这些几何形状对于许多工程应用都是有希望的。对加工样品的微观结构的观察表明，增强织物被环氧丙烯酸树脂浸渍得相当好。这些观察结果还表明，这两种类型的方法都能够实现树脂系统的完全有效的深度固化。