1. UKM Learning and Research Repository
2. PHD Thesis / Tesis PHD
3. Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

Title:	An investigation into passenger car structural dynamic behavior relationship to ride comport
Authors:	Zahir Hanouf (P36303)
Supervisor:	Mohd. Jailani Mohd. Nor, Prof. Dr.
Keywords:	Investigation into passenger car Passenger car structural dynamic Car structural dynamic behavior Ride comport Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	15-May-2014
Description:	Dynamic characterization of vehicle structures is a crucial step in NVC analysis and helps in refining the vibration and noise in new vehicles, which is becoming a marketing edge as well. Therefore understanding dynamic behavior of each structural part of the vehicle is a major requirement in improving the NVC characteristics of a vehicle. The main focus of this research is to investigate structural dynamic behavior of a passenger car using modal analysis part by part technique and apply this method to derive the interior noise sources. In the first part of this work computational modal analysis part by part tests were carried out to identify the dynamic parameters of the passenger car. Two softwares were used to carry out these tests namely VPG 3.2 and LS-Dyna. Finite elements models of the different parts of the car are constructed using VPG 3.2 software. Ls-Dyna pre and post processing was used to identify and analyze the dynamic behavior of each car components panels. These tests had successfully produced natural frequencies and their associated mode shapes of such panels like trunk, hood, roof and door panels. In the second part of this research, experimental modal analysis part by part is performed on the selected car panels to extract modal parameters namely frequencies and mode shapes. The study establishes the step-by-step procedures to carry out experimental modal analysis on the car structures, using single input excitation and multi-output responses (SIMO) technique. To ensure the validity of the results obtained by the previous method an inverse method was done by fixing the response and moving the excitation and the results found were absolutely the same. Finally, comparison between results obtained from both analyses showed good similarity in both frequencies and mode shapes. Conclusion drawn from this part of study was that modal analysis part-by-part can be strongly used to establish the dynamic characteristics of the whole car. Furthermore, the developed method is also used to show the relationship between structural vibration of the car panels and the passengers' noise comfort inside the cabin. Two analysis techniques were used for this matter, namely signal analysis and modal analysis. The main goal of these techniques is to identify the dominating frequencies inside the passenger car and then diagnose the structural vibration components that can be the sources of the interior noise. The results showed that the dominating peaks inside the passenger cabin is associated with the resonance of the front suspension system at 62 Hz and the resonance of the cross roof beam at 163 Hz and 173 Hz. These frequencies are in the frequency range of the passenger's discomfort. Even though, there is an arguing among researchers in the open literature review regarding the frequency range of discomfort, still the most researchers are agreed that the frequency range of discomfort can be either less than 100Hz or less than 200 Hz which is strongly agreed with the findings of this study. This study is conducted on a Malaysian passenger car, because studies on noise and vibration comfort in Malaysian automotive industry still in its infancy stage. Most researches conducted in Malaysia are concentrated on the measurement of the comfort or discomfort inside the cabin by using surveys. However, there is a lack of research about determination of the sources of noise and vibration that affects the passenger's discomfort. Therefore, it is important that both methods should be investigated in order to identify the sources of discomfort and how they affect the passenger's comfort, especially Malaysia has its own automotive industry. This studycan be considered as an important preliminary effort to understand the effect of noise and vibration towards Malaysian passengers comfort.,PhD
Pages:	189
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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