Page 144 - Biaxial Multiaxial Fatigue and Fracture

The Injuence of Static Mean Stresses Applied Normal to the Maximum Shear Planes in _.. 129

The tubular specimens (designs A and B) were cut using a numerically controlled lathe. The
exterior surfaces of the specimens were polished to a 6 pm finish. A surface finish of 12 to 16
pm was measured on the interior wall of the specimen after honing.

Testing and Results
The following loading sequences were applied to the biaxial specimens during the testing
program.

Pure Sheur, 0 Static Mean Strain Tests. Parts (a) and (b) of Fig. 5 show an example of the
loading history applied to a specimen to obtain a pure shear strain cycle on the maximum shear

1
&axial

Fig. 5. Schematic of pure shear, zero mean stress loading.