Assessment and prediction of mechanical wear life are imperative for ensuring the effective application, reducing maintenance cost and minimizing material waste, especially for the machines whose main failure modes are related to wear. For an assembled product, the prediction of wear life is difficult because there is no an appropriate method for direct measurement. The direct product of wear is believed to contain key information of the wear status of the contact surfaces and has been suggested as an indicator for mechanical failures. Currently, several online oil debris monitoring methods are proposed with high precision for accurate debris detection, but there is still a lack of a model to describe the relationship between the wear statu...