A technique for dynamic proportional multiaxial compression on soft materials

A novel experimental technique for imposing proportional dynamic confining pressure on specimens subjected to high strain rate compression was developed. A description of the experimental technique and experimental results on two polymeric materials are presented. The axial compression is provided by an aluminum split Hopkinson pressure bar (SHPB). The test section of the SHPB, together with the specimen, is sealed inside a small, fluid-filled pressure vessel. Upon axial loading, the shortened specimen results in a reduction in fluid volume, thereby generating lateral confining pressure on the specimen. This dynamic confining pressure is proportional to the axial loading on the specimen, with the proportionality depending on the properties and dimensions of the fluid and the specimen. Experimental results show that under dynamic confinement, the compressive strength of soft specimens increases significantly even at Experimental Setup low strains as compared with unconfined cases at high strain rates.