• 제목/요약/키워드: Durability Life

검색결과 802건 처리시간 0.03초

동적 특성을 고려한 차량 현가 시스템의 내구해석 기법 (Durability Analysis Technique of Automotive Suspension System Considering Dynamic Characteristics)

  • 한우섭;이혁재;임홍재;이상범
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.336-341
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    • 2003
  • In this paper, resonance durability analysis technique is presented for the fatigue life assessment considering dynamic effect of a vehicle system. In the resonance durability analysis, the frequency response and the dynamic load on frequency domain are used. Multi-body dynamic analysis, finite element analysis, and fatigue life prediction method are applied for the virtual durability assessment. To obtain the frequency response and the dynamic load, the computer simulations running over typical pothole and Belgian road are carried out by utilizing vehicle dynamic model. The durability estimations on the rear suspension system of the passenger car are performed by using the presented technique and compared with the quasi-static durability analysis. The study shows that the fatigue life considering resonant frequency of vehicle system can be effectively estimated in early design stage.

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차량내구시험과 시장 사용환경에서의 브레이크 패드 마찰재 마모수명에 대한 통계적 평가 (The Statistical Evaluation for the Wear Life of Brake Pad Linings in Vehicle Durability Test and Customer Usage Environment)

  • 서경원;정관영
    • 한국자동차공학회논문집
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    • 제7권5호
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    • pp.213-220
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    • 1999
  • The life data analysis of the system and component are useful to describe the result of reliability test in product life to satisfy customer's growing need and to change test specifications or design criteria by life data analysis. And vehicle durability tesr occurred market environment. In this study, a statistical analysis for the wear life of brake pad linings helped perform correlation procedure between vehicle durability test and market. B-life values of the brake pad wear life data from both vehicle durability test and marker usage were compared to determine acceleration of the test by the Weibull, normal and log-normal distribution. The acceleration coefficient of the vehicle durability test can access to evaluate design criteria of product and test specification.

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Durability design and quality assurance of major concrete infrastructure

  • Gjorv, Odd E.
    • Advances in concrete construction
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    • 제1권1호
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    • pp.45-63
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    • 2013
  • Upon completion of new concrete structures, the achieved construction quality always shows a high scatter and variability, and in severe environments, any weaknesses and deficiencies will soon be revealed whatever durability specifications and materials have been applied. To a certain extent, a probability approach to the durability design can take the high scatter and variability into account. However, numerical solutions alone are not sufficient to ensure the durability and service life of concrete structures in severe environments. In the present paper, the basis for a probability-based durability design is briefly outlined and discussed. As a result, some performance-based durability requirements are specified which are used for quality control and quality assurance during concrete construction. The final documentation of achieved construction quality and compliance with the specified durability are key to any rational approach to more controlled and increased durability. As part of the durability design, a service manual for future condition assessment and preventive maintenance of the structure is also produced. It is such a service manual which helps provide the ultimate basis for achieving a more controlled durability and service life of the given concrete structure in the given environment.

가상시험기법을 이용한 승용차 전륜 알루미늄 서브프레임 내구설계 (Durability Design of a Passenger Car Front Aluminum Sub-frame using Virtual Testing Method)

  • 남진숙;신행우;최규재
    • 한국생산제조학회지
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    • 제21권3호
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    • pp.368-375
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    • 2012
  • Durability performance evaluation of automotive components is very important and time consuming task. In this paper, to reduce vehicle component development time and cost virtual testing simulation technology is used to evaluate durability performance of a passenger car front aluminum sub-frame. Multibody dynamics based vehicle model and virtual test simulation model of a half car road simulator are validated by comparisons between rig test results and simulation results. Durability life prediction of the sub-frame is carried out using the model with road load data of proving ground which can evaluate accelerated durability life. We found that the durability performance of the sub-frame is sufficient and it can be predicted within short time compared to rig test time.

Prediction of RC structure service life from field long term chloride diffusion

  • Safehian, Majid;Ramezanianpour, Ali Akbar
    • Computers and Concrete
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    • 제15권4호
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    • pp.589-606
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    • 2015
  • It is well-documented that the major deterioration of coastal RC structures is chloride-induced corrosion. Therefore, regional investigations are necessary for durability based design and evaluation of the proposed service life prdiction models. In this paper, four reinforced concrete jetties exposed to severe marine environment were monitored to assess the long term chloride penetration at 6 months to 96 months. Also, some accelerated durability tests were performed on standard samples in laboratory. As a result, two time-dependent equations are proposed for basic parameters of chloride diffusion into concrete and then the corrosion initiation time is estimated by a developed probabilistic service life model Also, two famous service life prediction models are compared using chloride profiles obtained from structures after about 40 years in the tidal exposure conditions. The results confirm that the influence of concrete quality on diffusion coefficients is related to the concrete pore structure and the time dependence is due to chemical reactions of sea water ions with hydration products which lead a reduction in pore structure. Also, proper attention to the durability properties of concrete may extend the service life of marine structures greater than fifty years, even in harsh environments.

공진 주파수를 고려한 차량 섀시 부품의 피로해석 (Fatigue Analysis of Vehicle Chassis Component Considering Resonance Frequency)

  • 이상범;임홍재
    • 한국공작기계학회논문집
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    • 제13권6호
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    • pp.94-101
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    • 2004
  • The purpose of this raper is to assess the benefits of frequency domain fatigue analysis and compare it with more conventional time domain techniques. The multi-body dynamic analysis, FE analysis and fatigue life prediction technique are applied for the frequency domain fatigue analysis. To obtain the dynamic load history used in the frequency domain fatigue analysis, the computer simulations running over typical road Profiles are carried out by utilizing vehicle dynamic model. The fatigue life estimation for the rear suspension system of small-sized passenger car is performed by using resonance durability analysis technique, and the estimation results are compared with the conventional quasi-static durability analysis results. For the pothole simulation, the percent changes, of the fatigue life between the two durability analysis techniques don't exceed 10%. But for the Belgian road simulation because of the resonance effect, the fatigue life using the resonance durability analysis technique are much smaller estimated than the quasi-static durability analysis results.

파워스티어링 오일펌프용 풀리의 피로수명을 고려한 형상최적화 (Shape Optimization Considering Fatigue Life of Pulley in Power-Steering Pulley)

  • 심희진;김정규
    • 대한기계학회논문집A
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    • 제30권9호
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    • pp.1041-1048
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    • 2006
  • The pulley is one of core mechanical elements in the power steering system for vehicles. The pulley operates under both the compressive loading and the torque. Therefore, to assure the safety of the power steering system, it is very important to investigate the durability and the optimization of the pulley. In this study, the applied stress distribution of the pulley under high tension and torsion loads was obtained by using finite element analysis. Based on these results the fatigue life of the pulley with the variation of the fatigue strength was evaluated by a durability analysis simulator. The results at 50% and 1% for the failure probability were compared with respect to the fatigue life. In addition to the optimum design for the fatigue life is obtained by the response surface method. The response function utilizes the function of the life and weight factors. Within range for design life condition the minimization of the weight, one of the formulation, is obtained by the optimal design. Moreover the optimum design by considering its durability and validity is verified by the durability test.

차량 현가 시스템의 공진내구해석에 대한 연구 (A Study on Resonance Durability Analysis of Vehicle Suspension System)

  • 이상범;한우섭;임홍재
    • 한국음향학회지
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    • 제22권6호
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    • pp.512-518
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    • 2003
  • 본 논문에서는 차량시스템의 진동효과를 고려하는 내구평가를 위한 공진내구해석이 수행된다. 공진내구해석을 수행하는데 있어서 주파수응답과 주파수영역의 동하중이 사용된다. 다물체 동역학해석, 유한요소해석 및 피로수명예측기법이 가상내구 평가를 위해 적용된다. 주파수응답과 동하중이력을 얻기 위해 차량 다물체 모델을 이용하여 전형적인 파트홀과 벨지안로를 통과하는 컴퓨터 시뮬레이션을 수행한다. 공진내구해석기법을 사용하여 승용차의 후방 현가장치에 대한 내구평가를 수행하고 그 결과를 준정적내구해석결과와 비교한다. 본 연구를 통하여 차량 시스템의 공진주파수를 고려한 피로수명을 초기설계 단계에서 효과적으로 평가할 수 있다는 것을 알 수 있다.

Probability-based durability design software for concrete structures subjected to chloride exposed environments

  • Shin, Kyung-Joon;Kim, Jee-Sang;Lee, Kwang-Myong
    • Computers and Concrete
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    • 제8권5호
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    • pp.511-524
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    • 2011
  • Although concrete is believed to be a durable material, concrete structures have been degraded by severe environmental conditions such as the effects of chloride and chemical, abrasion, and other deterioration processes. Therefore, durability evaluation has been required to ensure the long term serviceability of structures located in chloride exposed environments. Recently, probability-based durability analysis and design have proven to be reliable for the service-life predictions of concrete structures. This approach has been successfully applied to durability estimation and design of concrete structures. However, currently it is difficult to find an appropriate method engineers can use to solve these probability-based diffusion problems. In this paper, computer software has been developed to facilitate probability-based durability analysis and design. This software predict the chloride diffusion using the Monte Carlo simulation method based on Fick's second law, and provides durability analysis and design solutions. A graphic user interface (GUI) is adapted for intuitive and easy use. The developed software is very useful not only for prediction of the service life but for the durability design of the concrete structures exposed to chloride environments.

Improving Durability Performance of Reinforced Concrete Structures with Probabilistic Analysis

  • Ferreira, Rui Miguel
    • International Journal of Concrete Structures and Materials
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    • 제2권2호
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    • pp.137-143
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    • 2008
  • In recent years, much research work has been performed on durability design and long-term performance of concrete structures in marine environments. In particular, the development of new procedures for probability-based durability design has been shown to provide a more realistic basis for the analysis. This approach has been successfully applied to several new concrete structures, where requirements for a more controlled durability and service life have been specified. For reinforced concrete structures in a marine environment, it is commonly assumed that the dominant degradation mechanism is the corrosion of the reinforcement due to the presence of chlorides. The design approach is based on the verification of durability limit states, examples of which are: depassivation of reinforcement, cracking and spalling due to corrosion, and collapse due to cross section loss of reinforcement. With this design approach the probability of failure can be determined as a function of time. In the present paper, a probability-based durability performance analysis is used in order to demonstrate the importance of the durability design approach of concrete structures in marine environments. In addition, the sensitivity of the various durability parameters affecting and controlling the durability of concrete structures in a marine environment is studied. Results show that the potential of this approach to assist durability design decisions making process is great. Based the crucial information generated, it is possible to prolong the service life of structures while simultaneously optimizing the final design solution.