• 대한조선학회지
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• 제7권2호
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• pp.27-40
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• 1970

The distribution of stress and strain in elastic stages is investigated by the experiments of two dimensional photoelastic coating and Moire fringe method. Center block type and cover plate type of fillet welds are used as specimens in the test. The results are as follows. 1) Center block type gets less uniform stress distribution than cover plate type. And its stress concentration factor, especially at root, is larger than that at toe. 2) When main plate and cover plate closely contact and it cause friction, stress concentration decreases more than that in case of slit. That is because stress can be transmitted on the contact surface. 3) When slit is made, the outside of fillet gets more stress than the inside of it. 4) While the plastic strain distribution of center block type reaches the maximum at root and differs very slightly from that under lower loading, the plastic strain distribution of cover plate type is inclined to get the maximum at the outside of fillet rather than at root. 5) When the plastic strain value of cover plate type is compared with that of center block type at toe and root, the relations between the former and the latter shows root<toe and root>toe. 6) Because stress distribution becomes changed according to loading, fracture angle cannot be estimated by the peaks of elastic stress distribution. 7) The strain distribution just before fracture can be found by Moire fringe method.

• 한국자동차공학회논문집
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• 제3권5호
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• pp.1-9
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• 1995

The purpose of this study is to develop a computer simulation program for analyzing load transmission characteristics of a helical gear system in design stage. In this analysis, the rotational delay, load distribution, root stress, and contact area are investigated. That is, the influence function of deflection is obtained by finite element analysis and the influence function of approach and gear tooth error are considered. Load distribution, rotational delay, and contact area are calculated by solving load-deflection equation which includes these influence functions and tooth error, and the influence function of the bending moment is obtained by finite element analysis. The root stress is calculated by the load distribution and the influence function of the bending moment. The results of the simulation are cross-checked through a specially designed experimental set-up.

• 한국정밀공학회지
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• 제23권11호
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• pp.126-134
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• 2006

In this study, the effect of stem-end design on contact pressure and stress distribution in revision TKR was investigated using finite element method. The finite element model of tibia, including the cortical bone, the cancellous bone and canal, was developed based on CT images. The implant models with various stem lengths, diameters, friction coefficients, and press-fit effects were considered. The results showed that the longer stem length, the stronger press-fit, the bigger stem diameter, and the higher friction coefficient increased both peak contact pressure and Von-Mises stress distributions. The results supported the clinical hypothesis that peak contact pressure and stress are related to the stem end pain. The results of this study will be useful to design the stem and reduce the end-of-stem pain in revision TKR.

• Tribology and Lubricants
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• 제19권6호
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• pp.357-364
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• 2003

The sub­surface stress field beneath the gear's contact surface caused by the contact pressure in lubricated condition has been calculated. To evaluate the influence of the clearance shape on the stress field, two kinds of tooth profile models were chosen. One is the conventional cylinder contact model and the other is the new numerical model. Love's rectangular patch solution was used to obtain the sub­surface stress field. The analysis results show that the sub­surface stress is quite dependent on both the contact pressure and the profile model. The maximum effective stress of the new model is lower than that of the old model. The depth where the maximum effective stress occurs in the new model is not proportional to the intensity of the external load.

• 한국철도학회논문집
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• 제6권2호
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• pp.142-148
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• 2003

A wheel and axle failure can cause a derailment with its attendant loss of life and property. The service conditions of railway vehicles have become severe in recent years due to a general increase in operating speeds. Damages of railway wheel are a spatting by wheel/rail contact and thermal crack by braking heat etc. One of the main source of damage is a residual stress. therefore it is important to evaluate exactly. A Residual stress of wheel is formed at the process of heat treatment when manufacturing. it is changed by contact stress developed by wheel/rail contact. Distributions of residual stress vary according to a magnitude of wheel load, a magnitude of friction when acceleration and deceleration. The objective of this paper is to estimate the influence of wheel motion on the residual stress distribution in the vicinity of the running surface.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.210-217
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• 1997

This paper presents the numerical results of the stress analysis of wheel-rail contact problems. Two models which have straight and tapered(1:20) contact geometries between the wheelset and rail are analyzed using the finite element approach. From the simulation results we found that the tapered geometry of wheel-rail contact base line showed very stable contact stress distributions for a whole contact position between the wheel and rail in a curved rail section. The FEM computed results may present an optimized geometry of wheel-rail contact in a high-speed railway system.

• Tribology and Lubricants
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• 제17권5호
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• pp.373-379
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• 2001

The problem of interest is formulating elastic contact problem of a layered semi-infinite solid in terms of Fourier integral. The plane strain problem is considered for a solid composed of homogeneous isotropic two layers with different mechanical properties. General solutions for the subsurface stress and deformation field of frictionless elastic bodies under normal loading using of Fourier transformation technique are obtained. The numerical results for the stress distribution of coated solid for some particular cases are given.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.663-667
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• 2003

Mechanical force acted on the rail wheel causes excessive wear and increases the maintenance cost. The present paper proposes newly designed wheel profiles in order to reduce the contact stress. Numerical analysis on the stress distribution of wheel-rail contact stress is carried out using ABAQUS, a commercial finite element code. The result of KNR1/40 conical wheel is compared to those of the proposed wheels, all of which are arc wheel profile type.

• Structural Engineering and Mechanics
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• 제83권3호
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• pp.341-351
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• 2022

During bolted flange assembly, the contact stiffness of some areas of the joint surface may be low due to the elastic interaction. In order to improve the contact stiffness at the lowest position of bolted flange, the correlation model between the initial bolt pre-tightening force and the contact stiffness of bolted flange is established in this paper. According to the stress distribution model of a single bolt, an assumption of uniform local contact stiffness of bolted flange is made. Moreover, the joint surface is divided into the compressive stress region and the elastic interaction region. Based on the fractal contact theory, the relationship model of contact stiffness and contact force of the joint surface is proposed. Considering the elastic interaction coefficient method, the correlation model of the initial bolt pre-tightening force and the contact stiffness of bolted flange is established. This model can be employed to reverse determine the tightening strategy of the bolt group according to working conditions. As a result, this provides a new idea for the digital design of tightening strategy of bolt group for contact stiffness of bolted flange. The tightening strategy of the bolted flange is optimized by using the correlation model of initial bolt pre-tightening force and the contact stiffness of bolted flange. After optimization, the average contact stiffness of the joint surface increased by 5%, and the minimum contact stiffness increased by 6%.

• 대한기계학회논문집A
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• 제23권11호
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• pp.2033-2039
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• 1999

One of the main causes of severe wear or crack initiation in wheel and rail is the contact stress due to wheel-rail contact. In this paper, the shape design based on more reasonable contact stress analysis rather than a general Hertzian contact theory is investigated in order to reduce the contact stress. The optimal design is performed using the simple 2-D finite element model and its results are verified by 3-D finite element analysis.