Stick–slip vibration and squeal noise from a rubber blade in contact with glass

Abstract

본 연구는 고무 블레이드와 유리의 상대운동에 의해 생성된 스퀼소음을 실험적으로 조사하고, 스퀼소음을 발생시키는 스틱-슬립 진동을 수치적으로 조사하였다. 윈드쉴드에서 와이퍼가 미끄러지는 거동을 나타내기 위해, 회전디스크와 고정 고무 블레이드를 사용하여 실험장치를 구성하였다. 실험장치를 통해 고무 블레이드 강성과 스퀼소음에 대한 상대속도의 영향을 조사하였다. 스퀼소음에 대한 일부 실험결과를 1자유도 스틱-슬립 이론모델을 통해 검증하고 설명하였다. 실험에서 확인하기 어려웠던 면내방향 진동이 스퀼소음에 미치는 영향을 확인하기 위하여, 바닥면의 축방향 변형을 고려한 새로운 스틱-슬립 진동 모델을 제안하였다. 첫번째로, 고무 블레이드와 회전하는 디스크 사이에서 발생하는 스퀼소음을 실험적으로 분석하였다. 스퀼소음을 규명하기 위해 소음과 진동을 측정하기 위한 실험을 수행하였다. 와이퍼 블레이드의 소음은 두 가지 실험 조건으로 측정되었는데, 고정된 와이퍼와 회전하는 유리를 이용한 실험과 고정된 윈드쉴드에서 와이퍼가 반복운동을 하는 조건에서의 실험이다. 와이퍼 블레이드 단면강성, 길이 변화 속도가 스퀼소음에 미치는 영향을 조사하였다. 스퀼소음은 고무 블레이드의 진동에 의해서 발생하며, 단면강성에 영향을 받지만 길이에는 영향을 받지 않는다. 또한 유리에 대한 와이퍼의 속도가 증가함에 따라 스퀼소음 주파수가 특정 주파수로 수렴하는 것으로 확인되었다. 그리고 스퀼소음과 스틱-슬립 진동과의 연관성을 1자유도 진동자 모델을 이용하여 분석하였다. 다음으로, 축방향 변형하는 양단고정 빔과 이송하는 진동자 사이에 발생하는 스틱-슬립 진동에 대해 조사하였다. 해석모델의 축방향 변형은 회전 디스크의 접선방향 변형을 나타낸다. 접선방향의 마찰력은 고무 블레이드와 유리사이의 접촉면 작용한다. 이론모델을 이용하여 운동방정식을 스틱상태와 슬립상태에 대해서 유도하고, 빔과 진동자 사이의 스틱-슬립 진동에 대해 분석하였다. 또한 축방향 변형에 의해 물체가 빔과 불규칙적으로 접촉하는 위치를 수학적으로 표현하였다. 수치해석을 통해 둘 사이에서 발생하는 긴 주기의 스틱-슬립 진동은 진동자에 의해 영향을 받고 짧은 주기의 스틱-슬립 진동은 빔 변형에 주로 영향을 받는 것을 확인하였다. 게다가 진동자에 높은 감쇠비가 부여되면, 빔의 변형에 의해 스틱-슬립 진동이 발생하는 것을 확인하였다. 마지막으로 진동자의 고유주파수의 고조파가 빔의 고유주파수와 일치하거나 가까워질 때 진동자와 내부공진이 발생되는 것을 확인하였다.|This study experimentally investigates the squeal noise generated by the relative motion of a rubber blade and a windshield, and numerically analyzes the stick-slip vibration generating the squeal noise. To implement the wiper’s sliding behavior on the windshield, an experimental setup was established that uses a rotating disk and a fixed rubber blade. This setup was used to investigate the effects of the rubber blade stiffness and the relative speed on squeal noise. Some experimental results for the squeal noise were validated and explained by using a theoretical single-degree-of-freedom stick–slip vibration model. To analyze the effects of in-plane vibration on the squeal noise, which is difficult to be identified in the experiment, we proposed a new stick–slip vibration model that includes the axial deformation of the bottom surface. First, the squeal noise between the rubber blade and the rotating disk was experimentally analyzed. In order to identify the squeal noise, we performed some experiments to measure noise and vibration. The squeal noises were measured with two experimental conditions: one is for a fixed wiper on a rotating glass disc, and the other is for a swinging wiper on a fixed windshield. We investigated the effects of the cross-sectional stiffness, length and speed of the rubber blade on the squeal noise. It is found that the squeal noise is caused by the high-frequency vibrations of the rubber blade and is influenced by the cross-sectional blade stiffness regardless of the change in dynamic characteristics due to the change in blade length. It is also found that the peak frequency of the squeal noise converges to a specific frequency as the speed of the rubber blade relative to the glass increases. Then, the relationship between the squeal noise and the stick-slip vibration was investigated by using the-single-degree-of-freedom stick-slip vibration model. Next, we investigate the stick–slip vibration between an axially flexible beam fixed at both ends and an oscillator moving on the beam. The axial deformation of the stick–slip model represents the tangential deformation of the disk. The friction force of the tangential direction acts on the contact surface between the rubber blade and the glass in the experiment. Using this theoretical model, the stick–slip vibrations between the oscillator and the beam were analyzed after deriving the equations of motion for the stick and slip states. In addition, to obtain the irregularly changed contact position due to the axial deformation of the beam and oscillator movement, a mathematical expression for the contact position was derived. It is found that the long-period stick–slip vibration is influenced mainly by the oscillator and the short-period vibration is influenced mainly by axial deformation of the beam. Furthermore, the dynamic responses show that even if a high damping ratio is applied to the oscillator, stick–slip vibration due to axial deformation of the beam can occur. And then, the analysis shows that a kind of the internal resonance occurs between the oscillator and the beam when the harmonics of the natural frequency of the oscillator match or approach the natural frequencies of the beam.; This study experimentally investigates the squeal noise generated by the relative motion of a rubber blade and a windshield, and numerically analyzes the stick-slip vibration generating the squeal noise. To implement the wiper’s sliding behavior on the windshield, an experimental setup was established that uses a rotating disk and a fixed rubber blade. This setup was used to investigate the effects of the rubber blade stiffness and the relative speed on squeal noise. Some experimental results for the squeal noise were validated and explained by using a theoretical single-degree-of-freedom stick–slip vibration model. To analyze the effects of in-plane vibration on the squeal noise, which is difficult to be identified in the experiment, we proposed a new stick–slip vibration model that includes the axial deformation of the bottom surface. First, the squeal noise between the rubber blade and the rotating disk was experimentally analyzed. In order to identify the squeal noise, we performed some experiments to measure noise and vibration. The squeal noises were measured with two experimental conditions: one is for a fixed wiper on a rotating glass disc, and the other is for a swinging wiper on a fixed windshield. We investigated the effects of the cross-sectional stiffness, length and speed of the rubber blade on the squeal noise. It is found that the squeal noise is caused by the high-frequency vibrations of the rubber blade and is influenced by the cross-sectional blade stiffness regardless of the change in dynamic characteristics due to the change in blade length. It is also found that the peak frequency of the squeal noise converges to a specific frequency as the speed of the rubber blade relative to the glass increases. Then, the relationship between the squeal noise and the stick-slip vibration was investigated by using the-single-degree-of-freedom stick-slip vibration model. Next, we investigate the stick–slip vibration between an axially flexible beam fixed at both ends and an oscillator moving on the beam. The axial deformation of the stick–slip model represents the tangential deformation of the disk. The friction force of the tangential direction acts on the contact surface between the rubber blade and the glass in the experiment. Using this theoretical model, the stick–slip vibrations between the oscillator and the beam were analyzed after deriving the equations of motion for the stick and slip states. In addition, to obtain the irregularly changed contact position due to the axial deformation of the beam and oscillator movement, a mathematical expression for the contact position was derived. It is found that the long-period stick–slip vibration is influenced mainly by the oscillator and the short-period vibration is influenced mainly by axial deformation of the beam. Furthermore, the dynamic responses show that even if a high damping ratio is applied to the oscillator, stick–slip vibration due to axial deformation of the beam can occur. And then, the analysis shows that a kind of the internal resonance occurs between the oscillator and the beam when the harmonics of the natural frequency of the oscillator match or approach the natural frequencies of the beam.