The investigation on a multi-body parachute cluster model

The complicated behaviors of parachute cluster systems, such as inter-canopy contact and lead-lag, were highly non-linear coupled with fluid and structural interaction (FSI). It was very difficult to analyze the cluster by the traditional design method using the cluster efficiency factor, or by the numerical simulation based on FSI which is still computationally challenging. In this paper, a simplified multi-body parachute cluster model was proposed by taking the entire cluster as a multi-body system and each parachute inside as an individual one. The inflating and inflated canopies were assumed as elastic bodies and the contact force between canopies was established by the penalty formulations. A typical parachute cluster used in the heavy cargo airdrop system (HCADS) was selected as an example, where there are four main parachutes. The inter-canopy contact and the lead-lag during the inflation process were simulated and verified by the airdrop tests. In summary, the proposed multi-body model is an effective numerical tool to design the parachute cluster, which can provide more detailed kinetic and kinematic characteristics of each canopy in the cluster with some coefficients properly achieved from the tests or numerical simulation.