Experimental and Numerical Testing of the V50 Impact Response of Flexible Fabrics: Addressing the Effects of Fabric Boundary Slippage

The impact testing of woven fabrics comprised of high strength and high modulus yarns is probabilistic in nature. This paper presents results from the experimental impact testing of 50.8 mm×50.8 mm scoured Kevlar S706 fabric samples held on four sides and impacted at the center by a 0.22 caliber ball bearing projectile. The V50 velocity response is obtained by performing impact experiments over a range of velocities and fitting the data to a normal distribution function. The impacted fabric samples show varying extents of slippage from underneath the fixtures. The effect of clamping pressure on the extent of fabric slippage is studied by varying the torque on the four bolts used to hold the fixtures together. Results from the experimental testing are compared against numerical predictions which did not consider fabric slippage effects. A simple new method to numerically model fabric slippage is developed and implemented into our computational probabilistic framework. Simulations are run using a Langlie method to obtain the new V50 velocity response of a Kevlar S706 fabric with spool based strength mappings and with boundary slippage present. Comparisons are then made between the experimental and numerical results.