Application of normalized energy method to inspection of bolt connection state in large engineering equipments

Bolt connection is one of the main connection forms of large engineering equipments, and its state directly affects safe operation of equipments. Thus, the detection of bolt connection state has important significance. However, for some bolts, in many cases the smaller components of the connection can not be excited and installed inspection elements, and the signal can be collected only on the larger foundation. In the paper, the energy about the vibration signals at various states of bolt connection was analyzed, and the correspondence relationship between the normalized energy of the fundation and the connection state. The test results indicated that the normalized energy of connection foundation varied with the tightening degree of the bolt connection, and the normalized energy method could be used to inspect the connection state.