This paper continues the evaluation of the feasibility of using a four-post road simulator to replicate operating conditions and perform response-only modal analysis on a truck frame. Work presented in this paper is continuation of a previous study that investigated the use of OMA methods for the same structure. This previous study helped in performing preliminary groundwork which included proof of concepts and suitability of existing techniques. Different excitation methods were employed and modal estimates from these tests were successfully validated against estimates from conventional EMA tests. However, the excitation methods employed in previous study were not true operational conditions. An attempt is made in this paper to employ more realistic operational conditions to excite the structure by using a four-post road simulator. Testing the truck frame using four-post road simulator poses several challenges due to factors such as effect of suspension systems, effect of dynamic boundary conditions, etc. which are close to situations encountered in real life. Considering that the excitations are vertical and restricted to the four wheelpan locations in this case, they do not satisfy the general OMA requirements of spatially well distributed excitations, and might pose challenges in modal parameter estimation. It should also be noted that other excitation conditions such as wind, driveline unbalance and engine vibration are not considered. In addition to utilizing OMA techniques, two other methods are considered. These methods compute transfer functions between measured outputs and measured input pressure and displacements (from the four-post road simulator), thus providing a function similar to a Frequency Response Function (FRF). These functions differ from conventional FRFs in terms of their numerical characteristics and form, and their applicability for modal parameter estimation is evaluated. Results obtained from the various tests are compared and validated with those from conventional EMA impact tests. From these results, the four-post road simulator is found to be marginally suitable for conducting modal tests involving OMA methods on the automotive structure. The displacement based pseudo FRF method also offer promising results, while shortcomings of the pressure based method are discussed.
Feasibility of using four-post road simulator for modal analysis of a truck frame
2009
26 Seiten, 25 Bilder, 2 Tabellen, 12 Quellen
Aufsatz (Konferenz)
Englisch
Optimal frame design of an off-road truck
Kraftfahrwesen | 2001
|Four-wheel steel frame truck and steel frame draft gear
Engineering Index Backfile | 1901
OPTIMAL FRAME DESIGN OF AN OFF-ROAD TRUCK
British Library Conference Proceedings | 2001
|British Library Conference Proceedings | 2003
|SAE Technical Papers | 1971
|