柔性伞衣织物的自由变形折叠建模及其充气机制研究

为解决冲压翼伞充气耦合计算中柔性伞衣织物的折叠建模这一关键技术难题,根据柔性伞衣真实的物理折叠特点,引入自由变形思想,提出针对多气室柔性伞衣织物的展向折叠建模方法。采用直接约束型曲面变形技术,通过控制节点移动实现曲面变形,基于坐标矩阵变换对柔性伞衣织物进行展向压缩折叠;并用初始应力方法修正几何误差,使折叠模型具有初始本构力学特征。对翼伞柔性伞衣织物建立展向折叠模型,基于任意拉格朗日-欧拉方法进行充气过程的流固耦合计算,得到充气过程中结构动力学变化及非稳态流场的分布情况,与空投实验进行对比分析,证明了基于自由变形的新型柔性伞衣织物折叠建模方法的准确性与可行性。

Free form deformation modeling method and inflation mechanism of folded canopy fabrics

Folded flexible canopy fabrics of ram-air parachutes modeling is a key problem in the interaction calculation during inflation process. According to physical folding characteristics, a modeling method of folded canopy fabrics was proposed based on free form deformation. The wing surface deformation was achieved by moving control nodes with direct constraint method of free form deformation. The spanwise folding was obtained by coordinate matrix transformation. In order to modify the geometric errors, the initial stress method was introduced to make the folded model with mechanical characteristics. The folded canopy fabrics model of a certain ram-air parachute was established using this method, and the fluid-structure interaction calculation was carried out based on the arbitrary Lagrange-Euler method during inflation process. The three-dimensional shape, stress and unsteady flow field distribution were obtained. The corresponding calculation and airdrop experiment verified the rationality and feasibility of this method.