Volume 6, Issue 5 (September 1978)
Powder-Cushion Gripping to Promote Good Alignment in Tensile Testing
A tensile testing technique utilizing a powder-cushion between the specimen/grip surfaces has been devised and tested. Bending strains associated with this gripping technique have been determined as a function of load with a buttonhead specimen instrumented with nine strain gages. Experiments with eight different powders showed that lubricating powders such as graphite and boron nitride are more effective in producing good alignment, with graphite considered superior. Alignment obtained with the graphite powdercushion is comparable with that obtained with more complex devices and procedures.