Transfer path analysis based on operational response data and consideration of the transmissibility function

Abstract

Complex mechanical systems such as those in ships, offshore plants, automobiles and home appliances often have noise, vibration and harshness(NVH) problems which must be studied to maintain the safety and satisfaction of the users. One of the best methods to study NVH behavior of a system is Transfer Path Analysis(TPA). It allows us to trace the flow of vibro-acoustic energy from the sources to the receiver through paths and to identify operational forces. TPA has proved to be a reliable method for assessing the NVH behavior especially in automobile industry. Despite its reliability, a novel method has consistently been demanded because TPA has limitations such as unequal boundary conditions with operating condition, long analysis time and complexity. In recent years, Operational Transfer Path Analysis(OTPA) has attracted interest of the industry as an alternative tool of TPA since OTPA is a simpler and faster method with correct boundary conditions than TPA. This study shows how to obtain more accurate transmissibility function, which is the main accuracy factor in OTPA, and compares between TPA and OTPA results. Furthermore, a strain transmissibility and novel hybrid transmissibility concept are proposed. It is also shown that the proposed transmissibility function can be used to estimate the strain in mechanical systems and therefore both strain gauge consumption and measurement time can be substantially reduced.