Title

Dynamic contact mechanics of thin membrane structures that wrinkle

Date of Completion

January 2001

Keywords

Engineering, Aerospace|Engineering, Civil

Degree

Ph.D.

Abstract

The motivation for this work is to model contact phenomena in thin membrane structures that wrinkle. Of special interest are parachute and airbag decelerator systems. Physical experiments have not yielded sufficient understanding of how contact affects performance of these systems. Numerical simulation can now provide an effective means for studying parachute and decelerator performance under various conditions. This research has expanded the numerical methods available to study parachute and airbag decelerator systems by developing the fundamental algorithms necessary to model contact in the discrete finite element setting utilizing well formulated continuum theory. In order to improve the efficiency of satisfying contact constraints, an alternative time integration scheme based on the Hilbert Hughes Taylor alpha method is developed. This new method takes advantage of the Augmented Lagrange method for satisfying contact constraints to calculate a discontinuous “jerk” in the acceleration due to contact. To demonstrate the effectiveness of the newly incorporated algorithms, four application problems are studied. These include an airbag soft-landing, intra-parachute canopy contact, a canopy impact with a rigid object, and inter-parachute canopy contact. ^