MSE Seminar Series: Jeffrey Swab
Friday, December 2, 2016
1:00 p.m.-2:00 p.m.
Room 2108, Chemical and Nuclear Engineering Building
Research Engineer at the U.S. Army Materials Lab
Static and Dynamic Compression Strength of Hot-Pressed Boron Carbide (B4C) Using a Dumbbell-Shaped Specimen
The compression strength of an armor ceramic influences its ballistic performance, but determining the intrinsic compression strength is very difficult. The specimen geometry and fixture used to apply the load, if not properly designed, can result in the generation of tensile stresses that lead to premature fracture and misleadingly low strength values. Often the compression strength is inferred from hardness values but this is not appropriate for ceramic materials. The compression strength is an input parameter in numerous modeling and simulation packages used to predict ballistic performance. Thus it is imperative that the compressive strength of candidate armor ceramics be properly and accurately measured. Dumbbell-shaped specimens were machined from a tile of a commercially available boron carbide material for evaluation. Quasi-static experiments were performed using a screw-driven load frame and the fracture process was recorded with a high-speed camera. Dynamic experiments were performed using a split-Hopkinson pressure bar setup with bars having the same diameter as the specimen and an ultra-high speed camera to record the fracture process. This presentation will summarize the results to date and identifies if a change in strain rate influences the compression strength value of boron carbide.