Decomposition method based on a modified Arcan fixture and its application in an in situ combined load tester

A miniature in situ tester integrated with a modified Arcan fixture was developed, providing simultaneous tensile and shear loading functions, to investigate the mechanical behaviors of bulk materials under combined loads or unidirectional load. Using the tester, a decomposition method was proposed to obtain the true tensile stress-strain and shear stress-strain relationships. Then, the feasibility of the decomposition method was verified via tensile loading, combined loading and shear loading tests on an extruded AZ31B magnesium alloy with initial gripping angles of 0 degrees, 45 degrees and 90 degrees, respectively. The tensile stress-strain curve and shear stress-strain curve were extracted from the combined stress-strain curve and compared with the results obtained from the unidirectional load tests. Finally, metallographic microscope images of the magnesium alloy under combined load conditions were captured as an illustration of the in situ function, and the fracture morphologies of the magnesium alloy under various loading conditions were also analyzed via a scanning electron microscope.