Folded Parachute Modeling Method Based on IMM

The parachute modeling with multilayer folding is a key problem that must be solved for the numerical simulation of folded parachute opening.According to the characteristics of parachute folding,a modeling method based on initial metric method modification was proposed.The folded model with local geometric errors was obtained firstly with space coordinate matrix transformation.Then the differences between the mapping and the reference configuration were calculated,and as the initial displacements were imposed on the mapping configuration.As a result,the initial element geometric errors caused by coordinate matrix transformation in the first step were modified.At last,a small parachute model with Z-shaped folding was established with this method.The corresponding calculation and wind tunnel test verified the feasibility and rationality of this method.This modeling method not only can resolve the problem of complicated folded parachute modeling,but also can guide the other fabric modeling which has large volume compression.