芳Ⅲ编织绳动态拉伸性能研究

芳Ⅲ编织绳是常见的降落伞伞绳材料，在开伞过程中承受较大的冲击载荷，为研究其动态拉伸性能，文章以3.5-750芳Ⅲ编织绳为例，进行了动态拉伸试验及仿真模拟。首先使用万能强力机对3.5-750芳Ⅲ编织绳开展了4个不同应变率工况下的动态拉伸破坏试验，获得拉力-等效应变曲线，研究发现随拉伸应变率的增加，编织绳的断裂强力和弹性模量均增大，而断裂应变和韧性均减小。随后利用ABAQUS软件，建立了芳Ⅲ编织绳的纱线级有限元模型，依据试验结果对Johnson-Cook动态本构模型进行拟合及参数修正，并应用于编织绳动态拉伸破坏仿真，得到不同应变率下的仿真结果。与试验对比，研究表明，拟合、修正得到的Johnson-Cook动态本构模型可有效地模拟柔性编织绳动态拉伸行为，为柔性编织绳的动态力学性能研究提供了仿真手段。

Study on Dynamic Tensile Properties of Aramid Ⅲ Braided Rope

Aramid Ⅲ braids is a common parachute rope material, which is subjected to a large impact load in the process of parachute opening. In order to study its dynamic tensile properties, this paper takes 3.5-750 aramid Ⅲ braided rope as an example to carry out dynamic tensile test and numericalsimulation. Firstly, the dynamic tensile failure tests of 3.5-750 aramid Ⅲ braided rope under four different strain ratesarecarried out by a universal strength machine, and the tension-equivalent strain curvesareobtained. It is found that with the increase of tensile strain rate, the breaking strength and elastic modulus of the aramid Ⅲ braids increase, while the breaking strain and toughness decrease. Then, the yarn-level finite element model of this type of the aramid Ⅲ braidsis established by using ABAQUS software. According to the test results, Johnson-Cook dynamic constitutive modelis fitted and the parametersaremodified, and then applied to the dynamic tensile failure simulation. The numericalsimulation results at different strain ratesareobtained and compared with the experimental results. Compared with the experiments, the results show that the fitting and modified Johnson-Cook dynamic constitutive model can effectively simulate the dynamic tensile behavior of flexible braided rope, which provides a simulation method for the study of dynamic mechanical properties of flexible braided rope.