Wide-Width Geotextile Testing with Video Extensometry
SourceThis paper demonstrates the difference between the results of using a conventional direct contact LVDT extensometer versus a non-contacting Video Extensometer where load at specific strains, ultimate load and elongation were measured. Previously, video extensometry has not been used for geotextile testing. Comparisons are made determining their measurement capability and ease of use. Direct contact systems displace yarns and rupture filaments in the fabric sample, which alter both the elongation and ultimate load of the sample. By measuring strain without placing a load on the yarns perpendicular to the loading direction, yarn slippage is eliminated. This principle allows for maximum tensile strength without pseudo failures due to yarn damage. Comparisons are also determined for length of time to calibrate, sample preparation before data acquisition, marking techniques and general observations made from using both systems.