Collaborative Fatigue Behavior under Wear and Fatigue Co-loads

The wear and fatigue tests of GDL-1 steels specimens were carried out by using a self-developed wear and fatigue equipment under different levels of strain ranging from 240 to 280 MPa with contact loads of 30 N. Through analyzing wear volume of specimens,the effect of wear and fatigue co-loads on fatigue life of specimens were studied. The propagation mechanism of micro-cracks on subsurface were observed by scanning electron microscopy,and the shear stress values below the contact surface were calculated by using Hertz Linear Elastic Theory and Smith Contact Theory. Experimental results show that under the wear and fatigue Co-loads,rheological effect of deformation layer made the fatigue micro-cracks expand gradually parallel with sheer stress direction,and contribute to improve fatigue life. Under this condition,a model of fatigue cracks propagation under wear and fatigue co-loads was proposed preliminarily. Calculation results show that the x_z in depth of 0.03 mm was the maximum and the specimens below depth of 0.18 mm may be caused plastic deformation to form the deformation layer.