Sandwich structured (SS) composites demonstrate considerable flexural stiffness and high strength-to-weight ratios and can be tailored as functional materials. Historically they have been constrained to specific material types and geometry due to limitations in manufacturing methods. However, employing additive manufacturing (AM), specifically direct ink writing (DIW), can provide an alternative method for making SS composites with complex and controllable micro and mesostructures with multifunctionality targeted at desired mechanical, thermal, and electrical properties. DIW, an extrusion-based AM technique, uses a viscous and thixotropic ink with desired components that, once printed, is cured to obtain the final complex net shape parts. In this paper, a novel hybrid AM technique is employed to manufacture SS composite materials containing bisphenol A-based epoxy core and carbon fiber reinforced polymer (CFRP) face sheets that are fabricated via DIW and vacuum infusion process (VIP), respectfully. We demonstrate that the fabrication of these SS composites can be tailored from a thermosetting material, from which additives and/or various lattice structures can be manufactured to achieve enhanced and desirable mechanical integrity with functional properties. Surface topology and mechanical testing techniques are used to characterize the fabricated hybrid SS composites to study and assess mechanical stability. A rheo-kinetic cure model was developed for the core material to allow for additive manufacturing process requirements while ensuring complete cross-linking for the thermoset-based core material. Because of the ability to obtain relatively small core-thickness and controlled architecture, this method now allows for fabricating layered micro-sandwich structures for realizing further light-weighting in relevant applications.

夹心结构 (SS) 复合材料表现出相当大的抗弯刚度和高强度重量比，并且可以定制为功能材料。从历史上看，由于制造方法的限制，它们一直受限于特定的材料类型和几何形状。然而，采用增材制造 (AM)，特别是直接墨水书写 (DIW)，可以提供一种替代方法来制造具有复杂且可控的微观和介观结构的 SS 复合材料，该复合材料具有针对所需机械、热和电性能的多功能性。DIW 是一种基于挤出的增材制造技术，它使用具有所需成分的粘性和触变性油墨，一旦印刷，就会固化以获得最终的复杂净形状部件。在本文中，一种新型的混合增材制造技术用于制造含有双酚 A 基环氧树脂芯和碳纤维增强聚合物 (CFRP) 面板的 SS 复合材料，这些面板分别通过 DIW 和真空灌注工艺 (VIP) 制造。我们证明了这些 SS 复合材料的制造可以由热固性材料定制，从中可以制造添加剂和/或各种晶格结构，以实现增强和理想的机械完整性和功能特性。表面拓扑结构和机械测试技术用于表征制造的混合 SS 复合材料，以研究和评估机械稳定性。为核心材料开发了一个流变动力学固化模型，以满足增材制造工艺要求，同时确保热固性核心材料的完全交联。由于能够获得相对较小的核心厚度和受控架构，该方法现在允许制造分层微夹层结构，以在相关应用中实现进一步的轻量化。