Abstract
Vehicle body and components (body structure, doors, hood, tailgate, mirrors, etc) are rigidly welded or attached to the vehicle body by means of articulated elements that allow a high level of mobility. In the latter case, for example, this may cause poor vibration performance of the part when exposed to oscillating loads such as the ones produced by the engine, the road irregularities and the aerodynamic forces. The poor vibration performance of a closure, for example, affects comfort perception and can cause squeak and rattle or lead to a high level of wind noise inside the vehicle. The problems associated with small displacements of these parts during driving conditions can be analysed using signal processing in both the time and the frequency domain. Also, from a practical point of view, the investigation of the relative movement of these elements with respect to the body shows a great potential for problem solving.
This paper presents case-studies based on the application of experimental methods for analysing the in-service movement of body parts, closures and vehicle parts using time and frequency domain signal processing in combination with geometrical equations that define the ‘spatial relationship’ between the measured points. These methods of analysis define the absolute and relative dynamic behaviour of these parts with respect to the vehicle body. It is shown that these methodologies are of particular interest in defining countermeasures to control the in-service displacements of any vehicle part and thus the information provided is of high interest for fatigue, NVH or comfort analysis.
KEYWORDS: Signal Integration, Time and Frequency Domain, Operational Deflection Shapes, Least Mean Square Application.