Development of a Pre-Validation Mode for Cooling Module by Test and CAE 2018-01-0466
In case of cooling module rotated by belt, many sources (vehicle’s vibration, belt’s tension and thrust force by rotated fan) are acting on it. Because it is not easy to analyze them individually, there were no rig test modes for pre-validation while developing a new vehicle.
In this study, we correlated the strain gauges signal to belt’s tension and fan’s thrust force, and measured acceleration of a vehicle and cooling module by driving a vehicle on the several test roads. In that case of measured acceleration data, we could analyze it by using PDF and construct the representative rig test modes considering vibrational fatigue characteristics by using the FDS. These modes can be utilized while developing a new vehicle without measuring anymore.
Also, we could understand each load’s characteristics. It is confirmed that the factors affecting the fatigue were not only the vehicle’s vibration but also the belt’s installation tension. So it needs to add belt’s installation tension as a static load condition for rig test. Since the domain frequency range of tension and thrust force while driving is lower than 2 Hz, the fatigue caused by tension and thrust force is not suitable by vibration rig test. This is because the minimum frequency applied by the actual vibration tester is from 5 Hz. So we realize that rig modes must contain not only the vibrational fatigue test but also static fatigue test. Another outcome is making fixture for testing the rig test modes, the fixture must have sufficient compliance to reduce the energy loss from actuator to cooling module. And the fixture must be compatible to allow easy installation of different cooling modules.