• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.591-594
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• 2000

In the recent day, fatigue life prediction techniques play a major role in the design of components in the ground vehicle industry. Full scale durability testing in the laboratory is an essential of any fatigue life evaluation of components or structure of the automotive vehicle. Component testing is particulary important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, 3-axis durability testing device is used to carry out the fatigue test. In this paper, The operation software for simultaneously driving 3-axis vibration testing device is developed and the displacement of the 3-axis actuator is separately calibrated by LDT Moreover, the input and output data are displayed in windows of PC controller with real time.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.156-163
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• 1996

The brakes are the most important safety-critical accident avoidance components of a motor vehicle. They must perform safely under a variety of operating conditions and must have enough strength not to fail during the life of a vehicle. Recently, anti-lock brake systems are used on more and more passenger cars. The ABS brakes modulate brake line pressure to prevent brakes from locking during braking. In this study, finite element analysis, material test for FCD45, measurement of stress and cumulative fatigue damage analysis were performed to evaluate fatigue damage of the caliper housing under ABS mode.

• 자동차안전학회지
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• 제14권3호
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• pp.30-34
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• 2022

The CFT(Cornering Fatigue test) and RFT(Radial Fatigue Test) are tests for evaluating the endurance of the disc and rim region of the wheel. In recent, automobile wheel safety standards have been revised and the applied load and target life criteria are different from existing conditions. The verification evaluation of all wheels requires a lot of time and cost. In this study, the endurance severity of each test was compared through strain-life approach by selecting 4 steel and 8 aluminum wheels.

• 한국철도학회논문집
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• 제2권2호
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• pp.31-38
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• 1999

Two representative types of the AGT (Automated Guideway Transit) system, which are bogie and steering types, are available for the side-guided system. Each system primarily consists of the bogie frame, suspensions, wheelsets and axles, braking system and transmission system. Among these components, the bogie frame is one of the most significant components subjected to the whole vehicle and passenger loads. This paper describes structural analyses and associated fatigue analyses for each bogie frame depending on the various loading conditions on a basis of the railway vehicle code UIC 515-4. Subsequently, comparisons are made between those two types to estimate which type is more reliable in terms of strength and fatigue. It is observed that the bogie type is a little advantageous over the steering one from the strength analysis. However, the two types are found to be in a reliable range of fatigue even though a realistic fatigue load case is further carried out. In addition, an optimal size of thickness is suggested for designs of the bogie frame.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.1-9
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• 2005

An end beam is one of the most important structural members supporting uncovered freight under in-service loading. In general, it needs to endure over 25 years. However fatigue fracture has occurred at dynamic stress concentration location of the end beam because user's specifications demanded high speed and vehicle manufacturer made the uncovered freight car with comparatively low strength and stiffness. For durability analysis, finite element analysis is performed to evaluate the problem of uncovered freight structure and local strain. The uncovered freight car was operated on actual problematic railroad line to measure dynamic stress versus time history on the critical part from which a crack is initiated often. Rainflow cycle counting method was used to estimate fatigue damage at dangerous area under operating condition. Therefore, this study shows that analytical fatigue life at the end beam can be predicted on the basis of S-N curve and structure analysis and has a fairly good correlation with experimental fatigue life.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.155.2-155.2
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• 2005

• 한국자동차공학회논문집
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• 제19권4호
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• pp.47-53
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• 2011

Firstly, FEM model for the body frame of a fuel cell vehicle was built up and design optimization results based on different schemes were exhibited. One scheme was to minimize weight while maintaining the normal mode frequencies and the other was to increase the frequencies without weight change. Next, for a rear frame model, shape parameter study on collapse characteristics such as peak resistance load and absorbed energy was carried out. Also, the stiffness of frame mounting brackets was predicted using inertance calculation and the durability of those mounting brackets for vehicle system loads was evaluated. Finally, for a representative mounting model, the influence on durability due to thickness change was analyzed.

• 자동차안전학회지
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• 제8권1호
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• pp.26-30
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• 2016

The steel road wheel on ventilation holes was cracked in the vehicle durability test. But the component durability test by uni-axial, CFT(Cornering Fatigue Test) and RFT(Radial Fatigue Test) had been satisfied. That is, the uni-axial component test could not forecast the crack of vehicle. Therefore this study developed the bi-axial test mode to reflect a vehicle condition(to reflect both vertical and lateral force simultaneously) based on real load data which was measured in Europe and China and developed CAE simulation too. It reproduced the cracks same as vehicle's and verified by bi-axial test machine in the LBF(Fraunhofer Institute for Structural Durability and System Reliability) durability research center in Germany. Finally this the durability CAE simulation by using HMC(Hyundai Motor Company)'s the bi-axial test mode predicts feasibly the steel wheel's durability performance before vehicle durability test.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.155-160
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• 2002

Metal matrix composites had generated a lot of interest in recent times because of significant in specific properties. It was also highlighted as the materials of frontier industry because strength, heat-resistant, corrosion-resistant, wear-resistant were superiored. In this study the strength properties of $Al_{18}B_4O_{33}/AC4CH$ were represented mixing the binder of $Al_2O_3$ and $TiO_2$. It was also fabricated by squeeze casting. $Al_{18}B_4O_{33}/AC4CH$ was fabricated at the melt temperature of $760^{\circ}C$ the perform temperature of $700^{\circ}C$ and mold temperature of $200^{\circ}C$ under the pressure of 83.4MPa and observed SEM. Fatigue crack growth rate tests on compact tension specimen(half-size) of thickness 12.5mm were conducted by using sinusoidal waveform. Compact tension specimens(half-size) were used and fatigue crack growth rate da/dN and stress intensity factor range ${\Delta}K$ were analyzed concerning to the R value of 0.1 and 0.05. In order to find out the value of ${\Delta}K$, load amplitude constant method was applied by the standard fatigue testing method describes in ASTM E647-95a. As the results of this study, Fatigue crack growth rate increased with in creasing the load ratio, Consequently, At equivalent stress intensity factors, the fatigue crack growth rates in MMC were faster than those of AC4CH alloy. then the fatigue life and the fatigue crack growth rate was investigated using scanning election microscopy(SEM)

• 한국자동차공학회논문집
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• 제6권1호
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• pp.143-150
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• 1998

The evaluation of joint fatigue strength of light weight materials for electrical vehicle body has been performed through single lap joint tests with the design parameters such as joint style, adherend, bonding overlap length and bonding thickness. Fatigue strength was evaluated through 5-Hz, tension-tension, load controlled test with the stress ratio zero value. It is experimentally observed that fatigue strength of joint increases for the increase of overlap length. The combinations of Al-Al and Al-FRP adherends show that fatigue strength of joint is hardly changed for the increase of bonding thickness, but FRP-FRP adherend specimen shows that fatigue strength of joint increases after decreases for the increase of bonding thickness. Al-Al adherend specimen has much higher fatigue length than Al-FRP and FRP-FRP adherend specimens. Riveting at adgesive bonded joint gives little effect on fatigue strength.