Extension measurement technique for rubber materials - utilises extension gauge comprising linear capillary tube in base of flexible material

摘要

An extensometer is employed to measure extensions of very deformable materials such as rubber which are subjected to an extending force. The gauge comprises a capillary whose electrical resistance is varied. An extension gauge comprises a thin U-shaped body (10) of flexible material in the base of which is a linear capillary tube (11) with wires (12) to the measuring circuit located in the arms. The bared ends of the wires are soldered to metal pods (13) which are in a perpendicular direction to the capillary and to which they are connected via elbow channels (14). These are of larger cross section that the capillary tube. The capillary is filled with an electrically conducting liquid such as mercury and is in contact with the pod assemblies. The gauge is glued to the piece under test and the resistance changes measured.