• Tribology and Lubricants
• /
• v.31 no.1
• /
• pp.6-12
• /
• 2015

This paper investigates the stick-slip characteristic of magnetorheological elastomer (MRE) between an aluminum plate and the surface of the MRE. MRE is a smart material and it can change its mechanical behavior with the interior iron particles under the influence of an applied magnetic field. Stick-slip is a movement of two surfaces relative to each other that proceeds as a series of jerks caused by alternate sticking from friction and sliding when the friction is overcome by an applied force. This special tribology phenomenon can lead to unnecessary wear, vibration, noise, and reduced service life of work piece. The stick-slip phenomenon is avoided as far as possible in the field of mechanical engineering. As this phenomenon is a function of material property, applied load, and velocity, it can be controlled using the characteristics of MRE. MRE as a soft smart material, whose mechanical properties such as modulus and stiffness can be changed via the strength of an external magnetic field, has been widely studied as a prospective replacement for general rubber in the mechanical domain. In this study, friction force is measured under different loads, speed, and magnetic field strength. From the test results, it is confirmed that the stick-slip phenomenon can be minimized under optimum conditions and can be applied in various mechanical components.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.24 no.5
• /
• pp.374-380
• /
• 2014

This article proposes a design guideline to reduce squeal noise generated by an automobile wiper blade. In order to explain the squeal noise phenomenon, a source of squeal noise is experimentally investigated using a rotating disk equipment, and then a single-degree-of-freedom stick-slip vibration model is established for a blade tip. Based on analytical results, we discuss a tendency of the squeal noise for various physical parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.680-681
• /
• 2014

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.3
• /
• pp.270-276
• /
• 2024

In this study, we analyzed the stick slip characteristics through friction experiments on materials used in mechanical and electronic products, and propose improvements to reduce abnormal noise generated inside refrigerators. To analyze the stick slip phenomenon of the materials, we fabricated a friction testing device and conducted friction experiments. Additionally, we measured the vibration and noise levels of internal components to analyze the occurrence and location of abnormal noise inside the refrigerator. By comparing the results of the refrigerator's phenomenon analysis and friction experiment, we confirm that the abnormal noise occurring inside the refrigerator is caused by the stick slip phenomenon of internal components. Finally, to propose improvements for abnormal noise reduction, we performed friction experiments using the Taguchi method and validated the performance of the proposed improvements by applying them to refrigerators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.376-377
• /
• 2008

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.255-261
• /
• 2002

A four-degree of freedom model is suggested to understand the basic dynamical behaviors of the normal interaction between two masses of the friction induced normal vibration system. The two masses may be considered as the pad and the disk of the brake. The phase space analysis is performed to understand complicated in-plane dynamics of the non-linear model. Attractors in the phase space are examined for various conditions of the parameters. In certain conditions, the attractor becomes a limit cycle showing the stick-slip phenomena. In this paper, on the basis of the in-plane motion not only the existence of the limit cycle but also the size of the limit cycle is examined o demonstrate the non-linear dynamics that leads the unstable state and then the normal vibration is investigated as the state of the in-plane motion For only one case of the system frequency(two masses with same natural frequencies), the propensity of the normal vibration is discussed in detail. The results show an important fact that it may be not effective when too much damping is present in the only one part of the masses.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.2
• /
• pp.116-125
• /
• 2003

Four models for stick-slip friction are presented and are adopted for a numerical simulation study for a manual transmission clutch damper in idle mode. Meaning of parameters for friction models are explained and proper values are suggested. Also explained ate the reason why those specific values for the parameters are chosen. Preferable model for the clutch damper In Idle mode is discussed in terms of calculation efficiency and fidelity of the model based on real measured data. For clutch damper idle mode simulation studies, all four models perform equally well.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.26 no.1
• /
• pp.55-62
• /
• 2016

Nuclear fuels are always exposed to hot temperature and high speed coolant flow during the reactor operation. Thus the fuel rod accompanies small amplitude vibration due to the turbulent flow. The random vibration causes friction between the fuel rod and the grid structure which provides the lateral supports. The friction is critical to the fuel rod fretting wear, and it degrades fuel performance when a severe wear is developed. LuGre friction model is introduced in the paper, and the performance was evaluated comparing to the classical Coulomb model. It is shown that the developed friction force considering the Coulomb friction is not enough to stop or delay the motion while the stick-slip can be simulated using LuGre friction model. Numerical solutions of the two dimensional spacer grid cell model with the modern friction are also reviewed, and it is discussed that the new friction model simulates well the nonlinear mechanism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.89-96
• /
• 2002

A two-degree of freedom model is suggested to understand the basic dynamical behaviors of the interaction between two masses of the friction induced vibration system. The two masses may be considered as the pad and the disk of the brake, The phase space analysis is performed to understand complicated dynamics of the non-linear model. Attractors in the phase space are examined for various conditions of the parameters of the model especially by emphasizing on the damping parameters. In certain conditions, the attractor becomes a limit cycle showing the stick-slip phenomena. In this paper, not only the existence of the limit cycle but also the size of the limit cycle is examined to demonstrate the non-linear dynamics that leads the unstable state. For the two different cases of the system frequency ((1)two masses with same natural frequencies, (2) with different natural frequencies), the propensity of limit cycle is discussed in detail. The results show an important fact that it may make the system worse when too much damping is present in the only one part of the masses.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.7
• /
• pp.502-509
• /
• 2002

A two-degree of freedom model Is suggested to understand the basic dynamical behaviors of the interaction between two masses of the friction induced vibration system. The two masses may be considered as the pad and the dusk of the brake. The phase space analysis is performed to understand complicated dynamics of the non-linear model. Attractors in the phase space are examined for various conditions of the parameters of the model especially by emphasizing on the damping parameters. In certain conditions, the attractor becomes a limit cycle showing the stick-slip phenomena. In this Paper, not only titre existence of the limit cycle but also the sloe of the limit cycle is examined to demonstrate the non-linear dynamics that leads the unstable state. For the two different cases of the system frequency[(1) Two masses with same natural frequencies, (2) with different natural frequencies] . the propensity of limit cycle Is discussed In detail. The results show an important fact that it may make the system worse when too much damping Is present in the only one part of the masses.