Application of a new geometrical approach to determination of combined stress endurance of insulating materials

The determination of combined-stress endurance requires that tests at single and combined stresses are performed. Such tests are shortened, their planning facilitated and interpretation of the results simplified and made more accurate by computer-aided manufacturing (CAM), the method of combined analysis of the data, based on a geometrical approach to combined stress life. An index is proposed to evaluate material endurance in combined-stress conditions, which can easily be determined by the E-T curves for long times to failure