Experimental Study on the Detection of Damage in Large-Scale Used Parts Using SIMO NOFRFs

In order to ensure the quality of remanufacturing parts, it is necessary to detect the fatigue damage in the used parts. NOFRFs have been characterized nonlinearity of the system and used to detect to the fatigue damage of the used parts. For the large-scale parts, the single-input multi-output system model (SIMO) and the estimation method for the NOFRFs of SIMO should be built. The new detection indexes based on SIMO NOFRFs were constructed with the concept of information entropy, the definition and estimation methods were given. The pulse hammer experiment was carried out on the used parts (reduction gearbox chassis with different fatigue damage), SIMO NOFRFs were estimated with the data of the hammer excitation measurement, and then the detection indexes could be calculated. The result showed that it is effective for the new detection index to evaluate synthetically the damage of large-scale used chassis parts.