The concept of identifying, characterizing and assessing sound transfer paths from sources to receiving points by applying transfer path analysis (TPA) has been keeping continuous interest since its introduction some 25 years ago. The attractive prospects of TPA-based clues to aimed modifications at particular sound sources and/or sound transmission paths have been confirmed by many successful applications of the approach. Nevertheless, the method still lacks full, undisputed acknowledgement and approval as a widespread tool of sound contribution analysis.
Apart from unrealistic early expectations this may be due to considerable measuring efforts to sufficiently describe all relevant sources. For this reason, the instrumental realization of the approach has been subject to continuous modifications to tighten up the procedure and to reduce its measuring and evaluating efforts.
Based on a review of the most relevant implementations of the TPA approach, the paper will compare the related benefits and drawbacks with respect to typical applications. Reducing the measuring effort typically limits insight to source mechanisms, thus limiting the predictive accuracy for source and transmission path modifications. However, the high performance in analyzing excitation and transmission of sound and vibration by handsome procedures makes this approach a most attractive and valuable tool for the NVH engineer.
This will be illustrated in particular for operational transfer path analysis where manageable efforts are obtained by registering truly operational data only. If evaluated properly, these data allow for valuable and targeting sound contribution analysis without tedious single measurements. Illustrated by examples from practical evaluations, the paper will review this methodology together with recent extensions like sensitivity analysis and thus outline realistic perspectives of TPA as an indispensable tool of demanding NVH engineering.