Deformation of MC-4 Ram-Air Canopy due to Control and Suspension Line Retraction

In the past two years we have developed expertise in using a nonlinear, finite element- based simulation software package to compute the inflated geometry of a ram-air parachute canopy from its cut-pattern. Specifically, we have examined the geometry of MC-4 parachute canopy with uniform and variable pressure distributions. Moreover, we have devised a set of metrics to compare the canopy geometry under various loading scenarios. The inflated canopy geometry is a key element for further CFD and FSI simulations. We propose to investigate in detail the effects of different line pull scenarios, including the length, number, and location of the lines (control ones at the trailing edge and/or the suspension lines on the edge), on the MC-4 canopy. In this manner, the effects of line pull on the canopy geometry would be found in a systematic way. Even though general knowledge exists regarding the way control lines affect the canopy, a quantitative means of assessing the variation of the canopy geometry with the line length would provide a deeper understanding and a useful tool for parachute system trajectory control schemes. The other aspect of the proposed effort is the continuation of support for the experimental test efforts in two different wind tunnels. Support would be provided not only in the data analysis and interpretation stage but also, and more importantly, in the design and implementation stage. A methodical approach in the test sequence and the importance of a complete set of diagnostic techniques are keys to a successful test campaign. This project will be primarily focused on characterizing the effects of suspension and/or control line lengths on the global geometry of the canopy under fixed pressure distributions.