Use of accelerated life tests on transmission belts for predicting product life, identifying better designs, materials and suppliers

Accelerated life tests (ALT) are useful in identifying better designs, materials and component suppliers, and also predicting component life in a shorter time. Therefore, ALTs are particularly useful during the product design stage. The use of an ALT in determining the proper transmission belt design in an appliance design is discussed herein. Meeting the reliability at the specified life under the normal operating conditions is the key design parameter. In this regard, a test fixture was designed to accelerate the main failure modes based on the previous experience. The common failure mode focused in this ALT is the breakage of the belt cords (that impregnated with rubber) due to the reverse bending at the idler-tension pulleys. Broken cords may increase the noise level. These are failures in the eyes of the customer and tend to occur long before the catastrophic failures. In this study, a transmission belts were run at three different stress levels, which facilitate a better extrapolation of normally operated life. At the beginning of the tests, a higher stress level was used in comparing and determining the better compound and the supplier in a shorter time. In the end, these tests and analyses were found to be helpful in determining the better material and also in predicting the life of the transmission belt at the normal operating conditions.