Block-programme fatigue testing of automobile wheel spindles automobile division

The paper reports the results of fatigue tests carried out on Ford Capri wheel spindle bodies. The first three programmes were aimed at investigating the effect of the sequence in which the loads were applied in a multilevel constant-frequency block programme. A further programme was carried out to investigate the effect on the fatigue life of removing the low-load cycles from the test sequence.The first three programmes demonstrated that the sequence in which individual blocks were applied had no significant effect on the fatigue life. From the fourth programme it was concluded that the removal of stress levels equal to and less than 1·75 times the r.m.s. (root mean square) value of the normal load frequency distribution had no effect on the fatigue damage. If these stress levels are removed there is an 87 1/2 per cent reduction in testing time. The slopes of the life function curves for all four programmes were nearly identical, and gave a mean value of 6·9 which is in agreement with other workers. Last...