• 제목/요약/키워드: archard's wear model

검색결과 29건 처리시간 0.021초

마멸에 의한 온간단조의 금형수명 예측에 관한 연구(I) -금형 마멸 모델의 정립- (A Study on Prediction of Die Life of Warm Forging by Wear(I) -Construction of Die Wear Model-)

  • 강종훈;박인우;제진수;강성수
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 1998년도 춘계학술대회논문집
    • /
    • pp.88-93
    • /
    • 1998
  • The service life of tools in metal forming process is to a large extent limited by wear, fatigue fracture and plastic deformation. In warm forging processes wear is the predominant factor for operating lives of tools. To predict tool life by wear, Archard's wear model is generally applied. Usually hardness of die is considered to be a function of temperature in Archard's wear model. But hardness of die is a function of not only temperature but also operating time of die. To consider softening of die by repeated operations, it is necessary to express hardness of dies by a function of temperatures and operating time. By experiment of reheating of dies, die softening curves were obtained. Finally modified Archard's wear model in which hardness of die was expressed as a function of main tempering curve was proposed.

  • PDF

Modification of Thin Film Friction and Wear Models with Effective Hardness

  • Kim, Chang-Lae;Kim, Hae-Jin
    • Tribology and Lubricants
    • /
    • 제36권6호
    • /
    • pp.320-323
    • /
    • 2020
  • Thin film coatings are commonly exploited to minimize wear and optimize the frictional behavior of various precision mechanical systems. The enhancement of thin film durability is directly related to the performance maximization of the system. Therefore, a fine approach to analyze the thin film wear behavior is required. Archard's equation is a representative and well-developed law that defines the wear coefficient, which is the probability of creating wear particles. A ploughing model is a commonly used model to determine the friction force during the abrasive contact. The equations demonstrate that the friction force and wear coefficient are inversely proportional to the hardness of the material. In this study, Archard's equation and ploughing models are modified with an effective hardness to minimize the gap between the experimental and numerical results. It is noted that the effective hardness is the hardness variation with respect to the penetration depth owing to the substrate effect. The nanoindentation method is utilized to characterize the effective hardness of Cu film. The wear coefficient value considering the effective hardness is more than three times higher than that without considering the effective hardness. The friction force predicted with the effective hardness agreed better with the results obtained directly from the friction force detecting sensor. This outcome is expected to improve the accuracy of friction and wear amount predictions.

Finite Element Model for Wear Analysis of Conventional Friction Stir Welding Tool

  • Hyeonggeun Jo;Ilkwang Jang;Yeong Gil Jo;Dae Ha Kim;Yong Hoon Jang
    • Tribology and Lubricants
    • /
    • 제39권3호
    • /
    • pp.118-122
    • /
    • 2023
  • In our study, we develop a finite element model based on Archard's wear law to predict the cumulative wear and the evolution of the tool profile in friction stir welding (FSW) applications. Our model considers the rotational and translational behaviors of the tool, providing a comprehensive description of the wear process. We validate the accuracy of our model by comparing it against experimental results, examining both the predicted cumulative wear and the resulting changes to the tool profile caused by wear. We perform a detailed comparison between the predictions of the model and experimental data by manipulating non-dimensional coefficients comprising model parameters, such as element sizes and time increments. This comparison facilitates the identification of a specific non-dimensional coefficient condition that best replicates the experimentally observed cumulative wear. We also directly compare the worn tool profiles predicted by the model using this specific non-dimensional coefficient condition with the profiles obtained from wear experiments. Through this process, we identify the model settings that yield a tool wear profile closely aligning with the experimental results. Our research demonstrates that carefully selecting non-dimensional coefficients can significantly enhance the predictive accuracy of finite element models for tool wear in FSW processes. The results from our study hold potential implications for enhancing tool longevity and welding quality in industrial applications.

등속조인트 외륜 열간단조의 금형수명 향상을 위한 단조공정 유한요소해석 (FE Analysis of Forging Process for Improving Tool Life in Hot Forging of CV Joint Outer Race)

  • 김용조
    • 한국기계가공학회지
    • /
    • 제13권3호
    • /
    • pp.56-62
    • /
    • 2014
  • During the hot forging process, the most common cause of tool failure is wear. Tool wear results in the gradual loss of part tolerances, after which eventually the tool must be replaced or repaired. In order to maximize the lifetimes of forging tools, it is important to investigate the wear mechanisms of these tools. In this study, the hot forging of the outer race of an automotive constant-velocity joint was analyzed by a finite element method to investigate the wear distribution, especially the amount and location of the maximum expected wear damage, using Archard's wear model, which was modified considering the forging temperature. Forging analyses were carried out after modifying blocker forging tools based on established versions. The modified blocker tools resulted in an increase in the tool life up to 31% with a finisher punch.

마모해석을 위한 고유치해석과 Adaptive Meshing 알고리듬을 이용한 수치해석 비교 (A Comparative Study on Eigen-Wear Analysis and Numerical Analysis using Algorithm for Adaptive Meshing)

  • 장일광;장용훈
    • Tribology and Lubricants
    • /
    • 제36권5호
    • /
    • pp.262-266
    • /
    • 2020
  • Herein, we present a numerical investigation of wear analysis of sliding systems with a constant speed subjected to Archard's wear law. For this investigation, we compared two methods: eigen-wear analysis and adaptive meshing technique. The eigen-wear analysis is advantageous to predict the evolution of contact pressure due to wear using the initial contact pressure and contact stiffness. The adaptive meshing technique in finite element analysis is employed to obtain transient wear behavior, which needs significant computational resources. From the eigen-wear analysis, we can determine the appropriate element size required for finite element analysis and the time increment required for wear evolution by a dimensionless variable above a certain value. Since the prediction of wear depends on the maximum contact pressure, the finite element model should have a reasonable representation of the maximum contact pressure. The maximum contact pressure and wear amount according to this dimensionless variable shows that the number of fine meshes in the contact area contributes more to the accuracy of the wear analysis, and the time increment is less sensitive when the number of contact nodes is significantly larger. The results derived from a two-dimensional wear model can be applied to a three-dimensional wear model.

마멸에 기초한 비대칭 열간단조 금형수명 예측에 관한 유한요소 시뮬레이션 (Finite Element Simulation on Prediction of an Asymmetric Hot Forging Die Life Based on Wear)

  • 최창혁;정경빈;김용조
    • 한국기계가공학회지
    • /
    • 제12권4호
    • /
    • pp.47-54
    • /
    • 2013
  • The main cause of die failure in hot forging is wear. Die wear directly generates the gradual loss of part tolerances, thereby causing deterioration in the dimensional accuracy of a forged part. It is very important to estimate forging cycles, called as die life, at which the die should be repaired or replaced. In this study, in order to estimate the hot forging die life, the finite element simulation of wear on an asymmetric part like a ball joint socket used in vehicle was carried out based on Archard's model. Finite element simulation results were compared with wear amounts of a used die that were measured using a contact stylus profilometer. The simulation results were in relatively good agreement with measurements obtained from the virtual die which was used by 7,000 forging cycles in a forging industry. Consequently, the die life in the hot forging of the ball joint socket was estimated by 10,500 forging cycles on the finisher die.

Spur Gear의 미끄럼 마멸률에 관한 연구 (A Study on the Sliding Wear Rate Calculation in Spur Gears)

  • 김태완;문석만;구영필;조용주
    • Tribology and Lubricants
    • /
    • 제16권5호
    • /
    • pp.357-364
    • /
    • 2000
  • In this study, the sliding wear in spur gears, using Archard's wear model, is analyzed. Formulas of tooth sliding wear depth along the line of action are derived. The tooth profile is modified Id make a smooth transmission of the normal loads and the cylinder profile for reducing the pressure spike is suggested. The sliding wear rate is calculated with these profiling results. We expect these modification methods to contribute to the reduction of sliding wear not only in the root, but the tip of tooth and tooth edge.

열연화를 고려한 금형마멸모델에 관한 연구(I)-마멸모델의 정립 (A Study on Die Wear Model considering Thermal Softening(I) -Construction of Wear Model)

  • 강종훈;박인우;제진수;강성수
    • 소성∙가공
    • /
    • 제7권3호
    • /
    • pp.274-281
    • /
    • 1998
  • The service life of tools in metal forming process is to a large extent limited by wear, fatigue fracture and plastic deformation. In elevated temperature forming processes wear is the predominant factor for tool operating life. To predict tool life by wear Achard's model is generally applied. Usually hardness of die is considered to be a function of temperature. But hardness of die is a function of not only tem-perature but also operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of a function of temperature and time. By experiment of reheating of die softening curve was obtained and applied to suggest modified Archard's Model in which hardness is a function of main tempering curve.

  • PDF

Ductile Cast Iron (DCI) 롤의 마모 특성 고찰 및 마모계수 도출을 위한 실험적 연구 (Experimental Study to Examine Wear Characteristics and Determine the Wear Coefficient of Ductile Cast Iron (DCI) Roll)

  • 변상민
    • Tribology and Lubricants
    • /
    • 제33권3호
    • /
    • pp.98-105
    • /
    • 2017
  • A pin-on-disk test is performed to measure the wear volume of a ductile cast iron (DCI) roll when it wears down using a high carbon steel and two alloy steels at different sliding velocities between the roll and the material (steel). Normal pressure is set as constant and test temperatures are 400, 500 and $600^{\circ}C$. In addition, thermal softening behavior of the DCI roll is examined using a high-temperature micro-hardness tester and the surface hardness variation of the DCI roll is expressed in terms of temperature and heating time. Based on experimental data, a wear coefficient used in Archard's wear model for each material is obtained. The wear volume is clearly observed when the test temperature is $400^{\circ}C$ and sliding velocity varies. However, it is not measured at temperatures of $500^{\circ}C$ and $600^{\circ}C$ even with variations in sliding velocity. From the optical photographs of the pin and disk, the abrasive wear is observed at $400^{\circ}C$ clearly, but no at $500^{\circ}C$ and $600^{\circ}C$. At higher temperatures, the pin surface is not smooth and has many tiny caves distributed on it. It is found that wear volume is dependent on the carbon contents rather than alloy contents. Results also reveal that the variations of wear coefficients are almost linearly proportional to the carbon contents of the material.

초고강도강판 프레스성형용 금형의 CrN 코팅층 마모수명 예측 (Wear Life Prediction of CrN Coating Layer on the Press Tool for Stamping the Ultra High Strength Steel Sheet)

  • 이정흠;배상범;윤국태;허재영;김세호;박춘달
    • 소성∙가공
    • /
    • 제26권3호
    • /
    • pp.137-143
    • /
    • 2017
  • In this study, a wear test method was proposed to predict the wear life of the CrN layer coated on the surface of the press tools for manufacturing the auto-parts with ultra high strength steel (UHSS) with a tensile strength of 1.5 GPa. The pin-on-disc type wear test was carried out to confirm the feasibility and the reproducibility of the wear amount according to the test conditions such as the normal force, the sliding velocity, and the sliding speed. The test conditions were obtained from the finite element stamping analysis and the wear simulation. With the wear amount from the wear test, a prediction model of the wear depth in the CrN coating layer was proposed according to the test conditions with the design of experiments such as Taguchi method and the response surface method. The derived prediction model was then compared to the result of the Archard wear model, fully describing that the proposed model can effectively predict the wear life of the press tools for the auto-parts with UHSS.