• 한국소음진동공학회논문집
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• 제13권12호
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• pp.903-910
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• 2003

A two-degree-of-freedom model is suggested to describe basic dynamical behaviors of the interaction between the pad and the disc of a disc brake system. Although a pad (and a disc) has many modes of vibration in practice, only one mode of each component Is considered. In this paper, a linear analysis is performed by means of the stability analysis to show various conditions for the system to become unstable, and is based on the assumption that the existence of limit cycle (this corresponds to an unstable equilibrium point inside the limit cycle) represents the squeal state of the disc brake system. The results of the stability analysis show that the damping of the disc is as much Important as that of the pad, whereas the damping of the pad only is considered In most practical situations.

• 한국소음진동공학회논문집
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• 제23권6호
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• pp.485-494
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• 2013

This paper deals with experimental evaluation methods for high speed judder on the brake-caliper system. Firstly, two types of brake caliper systems due to the wheel vibration was evaluated. Secondly, the high-speed judder of the brake was also investigated using the subjective rating evaluation in the high-speed road test. These experimental evaluations were carried out by changing the materials of brake pad and the specifications of the brake-corner module. Based upon the test results, a new specification of the brake pad, $15{\times}5$ vertical chamfer, was proposed. The new brake pad showed 3 points, 60 %, improvement in the subjective-rating evaluation comparing with conventional one. Besides, we need to decide properly with judder characteristic of pad material and have to carefully take into consideration other design parameters; caliper, disc, and the braking performance, durability, squeal noise.

• Tribology and Lubricants
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• 제24권4호
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• pp.163-169
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• 2008

Tribological properties of ceramic brake discs were investigated using a commercial friction material. The discs were manufactured by liquid silicon infiltration (LSI) into a C-C preform. The disc surface was modified by two different methods, producing sliding surfaces with chopped carbon fibers and carbon felt. In addition, the composition of the surface was also changed. Friction characteristics of the discs were examined using a 1/5 scale dynamometer. Results showed that the type and composition of the disc surface significantly affected the level of braking effectiveness and high temperature brake performance. The discs with felt surfaces showed higher friction levels than those with chopped fiber surfaces and SiC tended to increase the friction level while C lowered the friction coefficient. The ceramic disc was more sensitive to the deceleration rate than gray iron, showing high speed sensitivity.

• Steel and Composite Structures
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• 제19권4호
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• pp.939-952
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• 2015

In this paper, brake pad performance of two organic matrix composites namely, Sample 1 (contains no brass filler) and Sample 2 (contains 1.5% brass filler), is studied based on tribological and squeal noise behavior. In the first stage, a pin-on-disc tribometer is used to evaluate the frictional behavior of the two pads. On the following stage, these pads are tested on squeal noise occurrence using a drag-type brake dynamometer. From the two type of tests, the results show that; (i) brass fillers play a dual role; firstly as reinforcing element of the brake pad providing primary contact sites, and secondly as solid lubricant by contributing to the formation of a layer of granular material providing velocity accommodation between the pad and the disc; (ii) brass fillers contribute to friction force stabilization and smooth sliding behavior; (iii) the presence of small weight quantity of brass filler strongly contributes to squeal occurrences; (iv) there is close correlation between pin-on-disc tribometer and brake dynamometer tests in terms of tribological aspect.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.820-825
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• 2004

This paper deals with friction-induced vibration of disc brake system under constant friction coefficient. A linear, finite element parameter model to represent the floating caliper disc brake system is proposed. The complex eigenvalues are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model, the experimental modal test and the dynamometer test are performed. The comparison of experimental and simulation results shows a good agreement and the analysis indicates that mode coupling due to friction force is responsible for disc brake squeal. And squeal type instability is investigated by using the parametric rotor simulation. This indicates parameters which have influence on the propensity of brake squeal. This helped to validate the FEM model and establish confidence in the simulation results. Also they may be useful during real disk brake model.

• 자동차안전학회지
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• 제11권1호
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• pp.23-29
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• 2019

Recently, use of composite materials has been increasing for body structures and chassis parts in the car industry because of weight reduction effect and excellent mechanical thermal characteristics. However, application of composite materials in brake system is very difficult because it is hard to obtain enough brake performance due to low heat storage capacity of the composite materials. In this paper, we will present new carbon ceramic composite disc with high flow characteristic. To obtain this characteristic, new vent structures were designed by using ARIZ method and substance-field model analysis. The flow effect of these vent structures on the brake performance was verified by pugh matrix and cooling test. The test results show improvement of cooling performance up to $30^{\circ}C$. Finally, These results will improve brake the reliability of the brake performance for the high performance vehicles and electric vehicles.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.77-87
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• 2012

In this paper, the method and its effectiveness to decrease the uneven wear of the brake pad were proposed. A finite element analysis was performed to analyze the pressure distributions on the contact surfaces. The optimum brake pad shape was determined by a robust design using the Taguchi method. The effectiveness of the optimum design was clarified by the wear tests with a dynamometer.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.8-19
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• 2014

In this paper, a robust design of the back-plate of the brake pad to decrease the uneven wear of the pad was studied. A finite element analysis was performed to analyze the pressure distributions on the contact surfaces. Optimized back-plate shape of the brake pad was determined using the Taguchi method. The effectiveness of the robust design was clarified by the wear tests with a dynamometer.

• 한국소음진동공학회논문집
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• 제24권10호
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• pp.749-755
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• 2014

The analytical-finite element(FE) squeal model is applied to investigate the squeal propensity associated with contact stiffness of the disc brake system. The system contact stiffness is incorporated into the perturbed equations of motion in the analytical manner where the brake components are modeled by FE method. The results show that the contact stiffness of the friction material and the contact stiffness between the pads and caliper are the influential factors on the squeal propensity. Particularly, the modal instability of the 3200 Hz squeal mode drastically changes with respect to the contact stiffness between the pads and caliper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.630-634
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• 2001

Predicting brake squeal noise in design stage can be beneficial to reducing the expense of development. In this paper, the possibility of pre-estimating squeal phenomena of a disc brake system was investigated. To preestimate squeal phenomena, complex eigenvalue analysis was performed for brake system. The evaluation of noise dynamometer test verified the prediction and it corresponded with the result of complex eigenvalue analysis.