• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.791-795
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• 2014

In this paper, in order to impart the aging condition of the parts, by configuring the cycle of temperature from low temperature was performed by applying the aging conditions for vehicle cockpit module. The reason for the selected modules of the cockpit vehicle parts, because the joint occurrence typical components of the room component is a first module and ceiling cockpit module. After setting the excitation profile using the BSR exciter only that this is for the module degradation after the initial and grasp the change in the dynamic characteristics of the modules based on the before and after deterioration may be made in the module, grasp the noise generating position I measured the noise and proximity. Was also visualized on the position of the joint is generated using a sound camera to objective results occurring where the joint is selected through subjective evaluation.

• Composites Research
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• v.34 no.3
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• pp.192-198
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• 2021

Due to enormous market growing of electric vehicles without combustion engine, reducing unwanted BSR (buzz, squeak, and rattle) noise is highly demanded for vehicle quality and performance. Particularly, innerbelt weatherstrips which not only block wind noise, rain, and dust from outside, but also reduce noise and vibration of door glass and vehicle are required to exhibit high damping properties for improved BSR performance of the vehicle. Thermoplastic elastomers (TPEs), which can be recycled and have lighter weight than thermoset elastomers, are receiving much attention for weatherstrip material, but TPEs exhibit low material damping and compression set causing frictional noise and vibration between the door glass and the weatherstrip. In this study, high damping EPDM (ethylene-propylene-diene monomer)/PP (polypropylene) thermoplastic vulcanizates (TPV) were investigated by varying EPDM/PP ratio and ENB (ethylidene norbornene) fraction in EPDM. Viscoelastic properties of TPV materials were characterized by assuming that the material damping is directly related to the viscoelasticity. The optimum material damping factor (tanδ peak 0.611) was achieved with low PP ratio (14 wt%) and high ENB fraction (8.9 wt%), which was increased by 140% compared to the reference (tanδ 0.254). The improved damping is believed due to high fraction of flexible EPDM chains and higher interfacial slippage area of EPDM particles generated by increasing ENB fraction in EPDM. The stick-slip test was conducted to characterize frictional noise and vibration of the TPV weatherstrip. With improved TPV material damping, the acceleration peak of frictional vibration decreased by about 57.9%. This finding can not only improve BSR performance of electric vehicles by designing material damping of weatherstrips but also contribute to various structural applications such as urban air mobility or aircrafts, which require lightweight and high damping properties.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.449-455
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• 2016

This study provides the finite-element (FE) squeal-model predicting friction-induced noise with respect to several friction materials that have different friction characteristics. The friction curve and the corresponding friction noise were measured for four friction materials (Cu, Ni, Al, Mg) using the pin-on-disk and reciprocating friction system. The slope of the friction curve linearized at the sliding velocity was applied to the FE model. The unstable modes in the complex eigenvalue analysis were shown to correspond to the squeal frequencies that existed in the experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4776-4783
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• 2014

Many studies have examined the reduction of primary noise sources, but quality-related noise, such as BSR, is rarely studied. This study describes the quantitative BSR test method using a multi-axial simulator. The sine sweep test was conducted to detect the system resonance and its relation to BSR noise with high frequency. This method is applied to the seat frame with/without the vibration durability test. The results showed that the $1^{st}$ lateral resonance leads to higher BSR frequency noise. In addition, the reduction of the lateral mode system stiffness after the durability test results in a decrease in the BSR noise in sine sweep test mode.