Development of a Robust Static Punch Experiment for Screening Unprocessed Ultra-High Molecular Weight Polyethylene (UHMWPE) Unidirectional Cross-Ply Material.

摘要

At the request of the US Army Research Laboratory s Specifications and Standards Office, a novel experimental methodology for punch testing of Ultra-High Molecular Weight Polyethylene (UHMWPE) composites was developed. This test procedure will act as a quality-assurance test method and subsequently be an addendum to the new military specification MIL-DTL-32398. There are currently no intermediate mechanical testing methods to evaluate the production quality of new, unprocessed sheet material from UHWMPE manufacturers. Such methods are essential for assessing and predicting the acceptability of sheet goods prior to the curing/molding process relative to the product s ballistic performance. The primary challenge all laboratories face when testing unprocessed UHMWPE is gripping the slippery material to achieve repeatable data. We have designed and developed a relatively simple, cost-effective punch test procedure that addresses the issues associated with gripping UHMWPE composites during tests. A test protocol is presented that is simple, and the overall execution of the technique does not impose significant expense for test fixtures. This report details design iterations for the test fixture, specimen geometry, and gripping methods. Punch test results from the final fixture concept and experimental procedures have demonstrated repeatability for both load-displacement response and failure behavior in an unprocessed UHMWPE cross-ply composite sheet configuration.