目的 通过研究老化后的超高分子量聚乙烯(UHMWPE)无纬布力学特性，了解防弹衣在自然环境下的抗老化性能，为防弹装备使用和存储提供科学指导。方法 采用三维数字图像相关技术(3D-DIC)和万能材料试验机开展了其准静态拉伸力学性能测试。结果 十年自然老化后的UHMWPE无纬布应力应变曲线仍呈近似线性特征，但平均拉伸模量仅为18.0 GPa。结合试验过程中的全场应变变化过程，分析了UHMWPE无纬布试件的变形特性，发现拉伸过程中应变在分析区域内的分布较均匀。结论 十年自然老化后的UHMWPE无纬布软质防弹衣平均拉伸模量明显降低，防弹性能无法满足使用要求。

The work aims to study the mechanical properties of aged unidirectional UHMWPE sheets, and learn the aging resistance of body armors in natural environment and provide scientific guidance for the use and storage of bullet-resisting equipment. The quasi-static tensile mechanical properties of UHMWPE were tested by 3D-DIC and a universal material testing machine. The experimental results showed that the stress-strain curve of unidirectional UHMWPE sheets after ten years of natural aging was still approximately linear, but the average tensile modulus was only 18.0 GPa. The deformation characteristics of unidirectional UHMWPE sheets specimens were analyzed based on the whole field strain variation process in the test process. It was found that the strain distribution in the analysis area was uniform during the tensile process. After ten years of natural aging, the average tensile modulus of unidirectional UHMWPE sheet soft body armor is obviously reduced, and the bullet-resisting performance cannot meet the requirements of use.