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008 200715t20202020my a|||fram|| 001 0 eng d
020 _aTHE0008552(Local)
040 _aUMP
_beng
_cUMP
_erda
090 _aFTKMA .S24 2020 r Thesis
100 0 _aMohd Sahril Mohd Fouzi,
_eauthor.
245 1 0 _aIdentification of exhaust hanger location based on finite element model updating technique /
_cMohd Sahril Mohd Fouzi
264 1 _aKuantan, Pahang :
_bUMP,
_c2020
264 4 _a©2020
300 _axiv, 141 pages :
_billustrations (some color) ;
_c30 cm. +
_e1 CD-ROM
336 _atext
_2rdacontent
336 _atext
_2rdacontent
337 _aunmediated
_2rdamedia
337 _aunmediated
_2rdamedia
338 _avolume
_2rdacarrier
338 _avolume
_2rdacarrier
347 _atext file
_2rda
_bPDF
500 _aFaculty of Mechanical & Manufacturing Engineering
502 _aThesis (Master of Science) -- Universiti Malaysia Pahang – 2020
504 _aIncludes bibliographical references
520 3 _aThe development of exhaust structure to date has risen concerned among researchers and engineers due to the identification of suitable hanger location to suspend the structure on the vehicle’s chassis. This is because dynamic loads produced from uneven road condition and engine operational vibration that are transferred via hangers and propagated along the structure will affect the performance and lifespan of the exhaust structure. Hence, the present study proposed an approach to identify the best exhaust hanger location in order to improve the dynamic behaviour of the structure based on finite element (FE) model updating technique using normal mode analysis. Initially, the exhaust structure was modelled in computer aided design (CAD) software and imported into finite element analysis (FEA) software for pre-processing procedure. During the pre-processing phase, the FE model was treated with joint modelling strategy to represent the real welded exhaust structure since the joint itself gives a significant influence in the dynamic behaviour of a structure. Through joint modelling strategy, several element connectors such as rigid body element type 2 (RBE2), bar element connector (CBAR), beam element connector (CBEAM), and spring element connector (CELAS) available in the FEA software were used to model the welded joints. In order to verify the most reliable FE model with element connectors, the measured dynamic data from experimental modal analysis (EMA) were used and compared with the predicted result computed in FEA through correlation analysis. The measured dynamic data in this study were obtained from EMA using impact excitation with roving accelerometer technique. It was found that the FE model with CBAR element connector is feasible to replicate the real welded exhaust structure since it has the lowest discrepancy in correlation analysis. The discrepancy between the predicted results and its measured counterpart is appeared due to simplification made in modelled the complex geometry of exhaust structure and assumptions of material properties used during modelling process. Hence, FE model updating technique was adopted to reduce the discrepancy by adjusting the parameters iteratively. Prior to the updating process, sensitivity analysis was performed to select only sensitive parameters to be updated. The updating procedure managed to reduce the discrepancy from 4.10 % of error to 3.74 % of error. Then, the updated FE model was used for further analysis in identifying the best exhaust hanger location. In identifying the best hanger location, several case studies were designed with 35 numbers of hanger configurations. These hanger configurations for the FE model were computed using modal frequency response to evaluate its dynamic performance. Significantly, the maximum displacement of the original hanger location which was above 10 mm was successfully reduced less than 1 mm obtained from the 9th configuration. As a conclusion, a reliable FE model of welded exhaust structure has been successfully developed using joint modelling strategy and model updating technique, which later was effectively used in identifying the best hanger location numerically in minimizing the vibration effect with the reduction of displacement of the structure. This proposed method is valuable to be extended for other types of exhaust structures in identifying the best hanger location without involving any modification on the physical structure, which requires extra costs, efforts and time.
610 2 0 _aFaculty of Mechanical & Manufacturing Engineering
_xDissertations
650 0 _aUniversities and colleges
_xDissertations
650 0 _aTheses
942 _2lcc
_cTHESIS