Research Progress on Extendable and Foldable Structures

Abstract

Retractable and folding structures, as a key technology for addressing spatial constraints and achieving functional adaptability, are demonstrating increasingly broad and significant application prospects in aerospace engineering, modern architecture, and the development of various portable equipment. This paper aims to systematically trace the developmental trajectory and current research status of such structures within both academic and engineering circles globally, while thoroughly elucidating their core design principles. Through ingenious kinematic design and morphological configuration, these structures achieve controllable, reliable, and efficient morphological transitions between compact stowage and fully deployed operational states. This fundamentally enhances spatial resource utilization efficiency, alongside the structural system's functional adaptability and environmental responsiveness. Although notable progress and successful case studies have been achieved in specific engineering practices and application projects, substantial research challenges and academic frontiers remain at the fundamental level. These include developing systematic integrated design theories, elucidating dynamic operational mechanisms under complex conditions, characterizing performance under multi-physics coupling effects, and establishing comprehensive performance enhancement methods for global optimization. Subsequent sections of this paper will focus closely on core theoretical principles concerning the geometric composition, kinematic and dynamic analysis of scalable and foldable structures. Detailed discussions will be conducted in conjunction with their implementation forms, including grid-like structures, cable-rod systems, and folded plate configurations. The ultimate aim is to provide systematic, forward-looking, and reference-worthy academic support and literature basis for both theoretical innovation framework development and complex engineering application practice within this technological domain.