Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


ucin1277133229.pdf (3.27 MB)

ETD Abstract Container

Abstract Header

Feasibility of use of four-post road simulators for automotive modal applications

Sharma, Balaji R.
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277133229

Abstract Details

2010, MS, University of Cincinnati, Engineering : Mechanical Engineering.
Modal analysis is a critical part of the automotive development process. Identification of the vehicle's modal signature, especially in the low-frequency end of the spectrum, is essential for tuning the dynamic performance of the vehicle structure for optimal ride and handling comfort. Traditional methods to characterize the system - in terms of its natural frequencies, associated damping values and mode shapes - have typically employed conventional impact and shaker tests. While these tests are able to accurately study the modal behavior of the vehicle under static conditions, they are not truly reflective of the real-world operating conditions of the vehicle A four-post road simulator is used in automotive development to simulate on-road conditions in the laboratory primarily for durability, transmissibility, noise and vibration studies, etc. Some of these studies often involve a similar setup of response sensors across the automotive structure as conventional modal tests. Utilization of the road-simulator for modal analysis can potentially reduce the duration of the automotive development cycle in the testing phase, allowing for a faster time-to-market, in addition to improved accuracy of estimation of the vehicle's dynamic performance under simulated operating conditions. This thesis work explores the feasibility of using a four-post road simulator for experimental modal analysis (EMA) of automotive structures. The MTS 320 Road Simulator in the Structural Dynamics Research Laboratory, University of Cincinnati, is employed for the study, with a truck frame being the test structure. Frequency response functions (FRFs) are estimated with displacement and pressure measurements at the hydraulic excitation posts of the simulator, provided by transducers built into the four-poster, replacing force measurements as inputs. The applicability of these non-conventional FRF formulations for modal parameter identification using existing parameter estimation algorithms is studied. Additionally, response-only data based on random excitations from the simulator is processed under the framework of Operational Modal Analysis (OMA) for parameter estimation. Modal estimates from these tests are compared with one another and with those from conventional EMA-based impact tests, and a summary of results is presented based on the findings therein. The thesis begins with a general overview of the automotive testing process, and the role of experimental modal analysis and the four-post road simulator therein. Thesis objectives are presented in terms of utilizing the four-post road simulator for estimation of the modal parameters of automotive structures in the absence of force measurements, and the motivation for the same is discussed. Fundamental principles of experimental and operational modal analysis are presented further, in addition to the theory behind the use of non-force measurements in the measurement of modified FRFs and consequently the estimation of modal parameters. The document then proceeds to describe the experimental setup and the various tests conducted as a part of the study, with a summary of results from each test. A detailed discussion follows on the comparison of results between the tests, and an overall summary of results is presented. Conclusions from this research work are presented along with recommendations for future work in this area.
Randall Allemang, PhD (Committee Chair)
Allyn Phillips, PhD (Committee Member)
David Brown, PhD (Committee Member)
76 p.
Mechanical Engineering
Experimental Modal Analysis; Operational Modal Analysis; Automotive Testing; Four-post road simulators

Recommended Citations

Citations

  • Sharma, B. R. (2010). Feasibility of use of four-post road simulators for automotive modal applications [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277133229

    APA Style (7th edition)

  • Sharma, Balaji. Feasibility of use of four-post road simulators for automotive modal applications. 2010. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277133229.

    MLA Style (8th edition)

  • Sharma, Balaji. "Feasibility of use of four-post road simulators for automotive modal applications." Master's thesis, University of Cincinnati, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277133229

    Chicago Manual of Style (17th edition)

ucin1277133229
885
© 2010, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.