Title: Door-Closing Sound Quality Improvement Process Based on Beamforming Method, Wavelet Analysis, and Component Design Optimization
text: Door-closing sound quality is a very important noise, vibration, and harshness (NVH) attribute since it may have a significant impact on customers’ perception, recognition, and luxury sensation of an automobile brand. Therefore, its evaluation methodology and design process have been one of the research and engineering efforts for all NVH organizations in the automotive industry. In many cases, the resolution of a door-closing sound quality issue lacks a systematic approach, and engineers rush to work when an issue surfaces. While subjective evaluation may easily find a door-closing sound problem, it oftentimes cannot directly pinpoint and go right to the root cause of the issues, and engineers could only guesstimate the possible relevant structural components based on past experiences. In this work, a door-closing sound quality development process, which has already been implemented in vehicle programs, is summarized and presented. The process involves a systematic workflow in a relatively short turnaround time. It begins with the beamforming method to carry out the sound source localization to facilitate the accurate determination of the key areas that impact the door-closing sound quality and then followed by objective measurements to acquire the sound data for the examination of the temporal behavior and spectral content processed by the wavelet analysis. After a better understanding of the key components along with the sound characteristics obtained, the effort is then focused on the investigation of the component mechanisms and optimization of the relevant hardware kinematics. A case study based on a high-end passenger vehicle is presented, and in this particular example, it is found that the door latch design and weather strip on the upper window frame are the critical components. Once the design proposal is implemented, the door-closing sound quality has finally met the program target.