Simulation and Testing Assessment of Cruciform Parachutes using LS-DYNA® ALE

This work presents a model of the coupled aero- and structural dynamics for a cruciform parachute which can then be used to inform development of control schemes for autonomously guided airdrop systems. Currently, the United States Army uses a combination of ram-air parachutes, as part of the Joint Precision Airdrop System (JPADS), and ballistic unguided parachutes to deliver supplies in austere locations. Ram-air parachutes are highly maneuverable systems and when paired with Guidance, Navigation and Control (GN&C) flight software can be highly accurate. While a cruciform or cross parachute is significantly less maneuverable, it may offer a more cost effective alternative to deliver cargo and assist disaster relief efforts. By extending and retracting various suspension lines, which connect the payload to the parachute, different forces and moments can be manipulated for steering control. A two-way fluid-structure interaction (FSI) model was created using the LS-DYNA Arbitrary Lagrangian-Eulerian (ALE) solver. Quantitative and qualitative experimental and flight test data are used to validate the baseline model. Subsequent simulations investigate different control schemes and geometry changes to enable rapid testing and inform/guide future experiments and drop tests.