An experimental method for vibrational insertion loss of mechanical joints

摘要

An experimental method is presented in this paper to determine vibro-acoustic properties of mechanical joints. A new quantity, vibrational insertion loss, which is the vibration reduction introduced by a joint and is used to describe vibro-acoustic performance of a mechanical joint in a finite system, is introduced. Two test-rigs are manufactured and tested for planar and non-planar joints. Results show that for well-defined joints, repeatability and reproducibility of the suggested parameter less than 2 dB can be achieved. Comparisons are also made between the vibrational insertion loss and the vibration level difference. It is illustrated that the vibration level difference can only detect the change of modal behaviour of the system, while the vibrational insertion loss can be used to detect both changes of modal behaviour and of system damping introduced by the insertion of the joint. [References: 3]