연성효과를 고려한 강성요소 모델링을 통한 다중 조인트 구조의 진동/음향 해석 및 차량 래틀소음 발생 메커니즘 분석

Abstract

In this research, the method for analysis of rattle noise from structures of vehicles is proposed. Arrayed stiffness elements were used for investigation of the dynamic characteristics of the multi-jointed structures composed of welding components. For experimentations, multi-jointed specimens having various welding currents and different missing joints were produced. Vibration transfer characteristics by different joint strength were measured. In order to fully represent the vibration characteristics of the multi-jointed specimens, spectral element method (SEM) was used for theoretical modeling. The theoretical model composed of simple spring elements having translational and rotational springs showed limitations in representing the dynamic behaviors of the specimens. Correlated spring elements reflecting coupling effect by adjacent welding joints were proposed. In aspect of the vibration characteristics, the proposed model composed of correlated spring elements was verified by comparison with the measured results of the welding specimens. Joint strength of the specimens was quantitatively investigated based on the proposed model. The theoretical model was additionally verified by the simplified specimens of various multi-jointed structures like snap fits or fuel rod bundles. The proposed model was applied to the analysis of rattle noise generated from correlation among adjacent welding components of the vehicle. The vibration characteristics of rattle noise were verified by the experiment using the welding specimens having defects. The theoretical algorithm composed of the calculation process of the dynamic behaviors based on the modified governing equation and the determination process of the time of rattle generation was configured. The analytical results of the proposed algorithm using the simple model were verified by comparison with the measured signals of rattle noise. The predicted influence factors of rattle noise were considered based on the proposed algorithm and the SEM model of the welded structures. The effect of each single rattle factor was investigated. The analysis for the complex relationships among the various rattle factors were conducted. As a result, the prediction of the optimized relationship among the factors of vehicle rattle noise is possible by the proposed research.