Tuesday  |  Salon 11  |  05:20 PM–05:40 PM

#16232, Dynamic, Quasi-static, and Multi-axial Properties of Parachute Canopy Fabrics

The measurement of material properties of the fabrics used for the construction of parachutes is critical to a robust and safe design. With a comprehensive knowledge of material characteristics, it is possible to tune parachute designs in terms of cost and efficiency. Through quasi-static testing of selected materials intended canopy fabric, the salient material behavior has been determined concerning nonlinearity, hysteresis, recovery, anisotropy, and strain-rate dependence. Intermediate strain rate tests are needed to determine these properties at application relevant conditions, such as inflation and decent. Such characterization requires higher speeds than what is accessible in standard quasi-static load frames. The intermediate strain rate apparatus design presented in this work is based on a split-Hopkinson bar testing setup, which is modified for testing fabric specimens at rates of 1-100 /s. During such a test, the sample deformation is primarily observed with a high-speed camera. In this approach, the potential interference of gages on the mechanical response of the sample used in direct strain measurement is eliminated. Furthermore, full field and time resolved deformation maps may be determined via Digital Image Correlation (DIC) methodology. From DIC, it is possible to extract the in-plane strain components: axial, transverse, and shear. Force may also be calculated based on the mass and deceleration of the head assembly during the test. The results of testing on selected canopy fabrics at estimated deployment levels are presented.

Marinos Blanas   University of Massachusetts Lowell
Fernando Campos   University of Massachusetts Lowell
Patrick Drane   University of Massachusetts Lowell
Alex Krueger   University of Massachusetts Lowell
Al Witkowski   Katabasis aerospace
James Sherwood   University of Massachusetts Lowell
Alireza Amirkhizi   University of Massachusetts Lowell