Axiality of loading is very important in the tensile test, particularly under creep conditions. An experimental evaluation of bending of the test section using resistance strain gauges has been devised. This test showed that excessive bending was present in spite of the adoption of a coupling design recommended in the literature. The cause of bending was found to be solely due to a friction moment exerted by the pin joints which formed the essential feature of the couplings. A crossed knife-edge design was substituted for them with satisfactory results. Analysis of the pin joint showed it to be unsuitable for specimen alignment in the tensile test.

Axiality of loading in the tensile test

A creep laboratory for variable-load and variable-temperature testing in uniaxial tension has been established at the University of Newcastle upon Tyne. The philosophy behind the specification and design of the equipment is described, considerable attention having been paid to accurate control of the test environment. The method of processing experimental data, obtained with a data acquisition system, is outlined.

J M Booth

Papers

Equipment for creep testing at variable load and temperature