Abstract: With the progress of society and the times, various public transportation and high-rise buildings in cities have developed rapidly. The frequency of low-speed impacts such as falling objects and car collisions has also increased, posing economic and life-threatening risks to people. Therefore, there is an urgent need for protective equipment that can effectively resist the destructive effect of low-speed impact. Traditional protective materials are generally made of metals or high-strength ceramics. Due to their heavy weight and high stiffness, these materials lack flexibility and ductility, making it difficult to provide adequate protection for joint areas such as arms and legs. Therefore, the research and application of lightweight and flexible impact-resistant materials have become important topics in safeguarding people's lives. The development of impact-resistant materials has gone through many stages, from the initial hard materials such as steel plate and aluminum alloy plate to the later more lightweight and efficient materials such as EVA, EPS and EPP. These materials exhibit good flexibility under low strain rates but demonstrate high stiffness under high strain rates, effectively absorbing and distributing impact energy to reduce harm to the human body.
Shear Stiffening Gel (SSG), as a kind of intelligent shear hardening material, has the characteristics of dynamic weak cross-linking bond, nonlinear mechanical behavior and high energy dissipation efficiency. Upon impact, it can rapidly harden to absorb impact energy and then revert to its original state after the impact, demonstrating self-healing properties. Due to its unique strain rate sensitivity and shear hardening characteristics, SSG exhibits broad application prospects in various fields such as protective equipment, sensors and dampers. The introduction of different functional particles into SSG's multifunctional composites not only enhances its multifunctionality but also provides rigid support to the matrix, effectively mitigating the cold flow phenomenon of SSG.
SSG composites have potential advantages in the fields of energy dissipation and protection, and the stability and impact resistance of SSG can be effectively improved through various composite structure designs. These studies have demonstrated the benefits of SSG composites with different structures in energy dissipation within the realm of protection. Moreover, they have opened up new possibilities for the application of SSG in fields such as personal protection, artificial intelligence, military security, and healthcare, showcasing its immense scientific value and application prospects as an intelligent impact-resistant material. Exploring the mechanical properties of SSG and the principles behind it is essential to drive continued innovation in SSG applications. This article reviews the preparation techniques and mechanical properties of SSG, and analyzes the latest advancements in its functional improvements and practical applications. At the same time, the challenges in the research of SSG materials are also pointed out, and the development prospects of SSG materials are prospected.

Key words: shear stiffening gel, composites, impact resistance, personal protection, intelligent materials

摘要： 剪切变硬胶（SSG）复合材料因其应变率敏感和剪切硬化特性而备受瞩目。综合评述了SSG的研究进展，包括其合成技术、结构特性和材料改性，特别强调了添加功能性颗粒和创新复合结构设计可以提高SSG的稳定性和抗冲击性，还能有效改善SSG的冷流问题。此外，还探讨了SSG的复合技术、力学行为、功能化改进及其在实际应用中的新进展，并指出了当前研究面临的挑战，同时对其在智能抗冲击材料领域的未来发展潜力进行了展望，凸显了SSG在该领域的重要科学和应用价值。

关键词: 剪切变硬胶, 复合材料, 抗冲击性, 人体防护, 智能材料