The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
Wonseok Jung - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Design of Leaf Spring Using Artificial Neural Network
Key Engineering Materials, 2006Co-Authors: Wonseok Jung, Gee Wook Song, Jung Seob HyunAbstract:The vehicle suspension system is directly influenced to ride and handling. Therefore, the major components of the vehicle suspension system should have enough Fatigue strength during its lifetime to protect passenger from the traffic accident. Spring is one of the major suspension part of vehicle. Thus, in this paper, a Fatigue Design method for leaf spring was proposed. At first, numerical stress analysis for leaf spring assembly was performed. On the base of the analysis results, Fatigue strength of leaf spring was assessed. And next, after studying numerically on geometrical parameters of leaf spring assembly, an economical prediction method of Fatigue Design Criterion for leaf spring assembly using the theory of artificial neural network was developed and certified its usefulness. Without performing a lot of additional Fatigue test for a long time, Fatigue Design Criterion for a new leaf spring assembly having different geometry can be predicted on the base of the already obtained Fatigue data.
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Stress Analysis of the Automobile's Coil Spring Including Residual Stresses by Shot Peening
Key Engineering Materials, 2006Co-Authors: Wonseok JungAbstract:Durability assessment for the suspension system of the vehicle is very important. In order to secure reliability on the results of durability assessment and Fatigue Design Criterion, accurate stresses for the interesting component must be basically calculated. In this paper, numerical stress analyses for the automobile’s coil spring were performed. Residual stresses by shot peening were also analyzed. The effects of the stress analysis results on Fatigue strength of the coil spring were discussed. From the results, Fatigue durability of the shot peened coil spring could be considerably improved by the effects of compressive residual stress. However, being attacked by corrosive environments, it could decrease by corrosion Fatigue degradation.
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Fatigue Design Criterion of lcv leaf spring based on road load response analysis
Key Engineering Materials, 2005Co-Authors: Ilseon Sohn, Wonseok Jung, Won Wook JungAbstract:Suspension system of light commercial vehicle (LCV) has enough endurance to protect passenger and freight. Leaf spring is major part of LCV suspension system. Thus, Fatigue strength evaluation of leaf spring based on road load response was carried out. At first, the strain of leaf spring was measured on the city mode driving condition and proving ground driving condition. And , the damage analysis of road load response was carried out. After that, Fatigue test of leaf spring was also carried out. Based on e-N life relation, Fatigue life of leaf spring was evaluated at Belgian mode, city mode and drawing test specification called the 3 steps test mode. Next, it is compared the Design life of leaf spring and evaluated Fatigue life by the 3steps test mode. From the above, new target of Belgian mode and city mode was proposed to gratify Design specification of leaf spring. It is expect that the proposed target can be satisfied leaf spring Fatigue endurance at specific road condition.
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The Influence of Residual Stresses by Shot Peening on Fatigue Strength of the Automobile's Coil Spring
Key Engineering Materials, 2005Co-Authors: Wonseok Jung, Soon-cheol Park, Won Wook JungAbstract:Durability assessment for the suspension system of the vehicle is very important. Particularly, corrosion Fatigue strength of coil spring depends on many factors including mechanical and environmental properties. In this paper, residual stresses by multiple shot peening were analyzed using finite element analysis, and evaluated its effect on corrosion Fatigue strength. And also, a corrosion Fatigue Design Criterion for coil spring of light commercial vehicle (LCV) based on proving ground response was proposed.
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Fatigue Design of Leaf Spring Based on Proving Ground
Key Engineering Materials, 2004Co-Authors: Ilseon Sohn, Wonseok Jung, Seo-jung ParkAbstract:The suspension system of vehicle is directly influenced to ride and handling. Therefore, suspension part should have enough endurance during its lifetime to protect passenger. Spring is one of major suspension part of vehicle. Thus, in this paper, a Fatigue Design method for leaf spring based on proving ground response was proposed. At first, stress and displacement of leaf spring are measured through the proving ground test. And next, the maximum load acting on leaf spring assembly under driving condition was defined from the road load response. On the base of these results, Fatigue tests for leaf spring assembly and 3-point bending Fatigue tests for material of leaf spring were carried out. From the above, the maximum load-Fatigue life relation of leaf spring material and assembly was defined, and 3-point bending test result has good agreement with leaf spring assembly Fatigue test result. Thus, it is expect that economical Fatigue Design Criterion for leaf spring assembly can be determined from Fatigue data of simple smooth specimen by 3 point bending Fatigue tests.
Ilseon Sohn - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Design Criterion of lcv leaf spring based on road load response analysis
Key Engineering Materials, 2005Co-Authors: Ilseon Sohn, Wonseok Jung, Won Wook JungAbstract:Suspension system of light commercial vehicle (LCV) has enough endurance to protect passenger and freight. Leaf spring is major part of LCV suspension system. Thus, Fatigue strength evaluation of leaf spring based on road load response was carried out. At first, the strain of leaf spring was measured on the city mode driving condition and proving ground driving condition. And , the damage analysis of road load response was carried out. After that, Fatigue test of leaf spring was also carried out. Based on e-N life relation, Fatigue life of leaf spring was evaluated at Belgian mode, city mode and drawing test specification called the 3 steps test mode. Next, it is compared the Design life of leaf spring and evaluated Fatigue life by the 3steps test mode. From the above, new target of Belgian mode and city mode was proposed to gratify Design specification of leaf spring. It is expect that the proposed target can be satisfied leaf spring Fatigue endurance at specific road condition.
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Fatigue Design of Leaf Spring Based on Proving Ground
Key Engineering Materials, 2004Co-Authors: Ilseon Sohn, Wonseok Jung, Seo-jung ParkAbstract:The suspension system of vehicle is directly influenced to ride and handling. Therefore, suspension part should have enough endurance during its lifetime to protect passenger. Spring is one of major suspension part of vehicle. Thus, in this paper, a Fatigue Design method for leaf spring based on proving ground response was proposed. At first, stress and displacement of leaf spring are measured through the proving ground test. And next, the maximum load acting on leaf spring assembly under driving condition was defined from the road load response. On the base of these results, Fatigue tests for leaf spring assembly and 3-point bending Fatigue tests for material of leaf spring were carried out. From the above, the maximum load-Fatigue life relation of leaf spring material and assembly was defined, and 3-point bending test result has good agreement with leaf spring assembly Fatigue test result. Thus, it is expect that economical Fatigue Design Criterion for leaf spring assembly can be determined from Fatigue data of simple smooth specimen by 3 point bending Fatigue tests.
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Fatigue Design of various type spot welded lap joints using the maximum stress
KSME International Journal, 2004Co-Authors: Wonseok Jung, Ilseon SohnAbstract:Recently, a new issue in Designing spot welded structures such as automobile and train car bodies is to predict an economical Fatigue Design Criterion. One of the most typical and traditional methods is to use a ΔP—N_f curve. However, since the Fatigue data on the ΔP—N_f curve vary according to the welding conditions, materials, geometry of joint and Fatigue loading conditions, it is necessary to perform the additional Fatigue tests for determining a new Fatigue Design Criterion of spot-welded lap joint having specific dimension and geometry. In this study, the stress distributions around spot welds of various spot welded lap joints such as in-plane bending type (IB type), tension shear type (TS type) and cross tension type (CT type) were numerically analyzed. Using these results, the ΔP—N_f curves previously obtained from the Fatigue tests for each type were rearranged into the Δσ - N _ f relations with the maximum stresses at the nugget edge of the spot weld.
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A Fatigue Design Method of Spot-Welded Lap Joint Using Neural Network
International Journal of Modern Physics B, 2003Co-Authors: Wonseok Jung, Ilseon SohnAbstract:In order to establish a long life Fatigue Design Criterion of spot-welded thin sheet structures such as the automobile and the train bodies, an economical method was proposed. As a mechanical parameter to determine the Fatigue Design Criterion of spot-welded structure, the maximum stress equation was defined by using artificial neural network. By using the maximum stress equation and the Fatigue data previously obtained as the Fatigue test results, the Fatigue Design Criterion of spot-welded joint could be predicted without any additional Fatigue tests. The results predicted by this method showed good agreement with actual Fatigue test results.
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Fatigue Strength Evaluation of Spot-Welded Multi-Lap Joint by the Maximum Stress Intensity Factor, Kθmax
International Journal of Modern Physics B, 2003Co-Authors: Wonseok Jung, Ilseon SohnAbstract:Fatigue strength and reliability of structural components in railroad commercial vehicles are usually decided by spot weld. Thus, it is very important to develop a Fatigue Design method for spot welded multi-lap joints in railroad commercial vehicles. The objective of this paper is to provide an integrated Fatigue Design Criterion for spot-welded multi-lap joints used in the body of railroad commercial vehicles. Based on finite element analysis, the Fatigue life data for spot-welded multi-lap joints is correlated in terms of the maximum stress intensity factor, Kθmax, that is the fracture mechanical parameter. From the results, using Δ Kθmax - Nf relationship, a proper Fatigue life Design rule independent on geometric variables and material properties for components having spot welded multi-lap joints can be established.
Seung Yeb Baek - One of the best experts on this subject based on the ideXlab platform.
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Fracture Mechanics Approach to X-Ray Diffraction Method for Spot Welded Lap Joint Structure of Rolled Steel Considered Residual Stress
Transactions of The Korean Society of Mechanical Engineers A, 2011Co-Authors: Seung Yeb BaekAbstract:Cold and hot-rolled carbon steel sheets are commonly used in railroad cars or commercial vehicles such as the automobile. The sheets used in these applications are mainly fabricated by spot welding, which is a type of electric resistance welding. However, the Fatigue strength of a spot-welded joint is lower than that of the base metal because of high stress concentration at the nugget edge of the spot-welded part. In particular, the Fatigue strength of the joint is influenced by not only geometrical and mechanical factors but also the welding conditions for the spot-welded joint. Therefore, there is a need for establishing a reasonable Criterion for a long-life Design for spot-welded structures. In this thesis, P-N Δ f relation curves have been used to determine a long-life Fatigue-Design Criterion for thin-sheet structures. However, as these curves vary under the influence of welding conditions, mechanical conditions, geometrical factors, etc. It is very difficult to systematically determine a Fatigue-Design Criterion on the basis of these curves. Therefore, in order to eliminate such problems, the welding residual stresses generated during welding and the stress distributions around the weld generated by external forces were numerically and experimentally analyzed on the basis of the results, reassessed Fatigue strength of gas welded joints.
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Reliability assessment and prediction of a Fatigue Design Criterion for the gas-welded joints
Journal of Mechanical Science and Technology, 2010Co-Authors: Seung Yeb BaekAbstract:Gas metal arc welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle structures. However, since the Fatigue strength of the joints welded by gas metal arc welding is considerably lower than that of the parent material due to stress concentration and metallurgical changes at the weld, the Fatigue-strength assessment of welded joints is very important for the reliability and durability of railroad cars and the establishment of a Criterion for long-life Fatigue Design. In this paper, in order to save time and cost for the Fatigue Design, an accelerated life-prediction method that is based on the theory of statistical reliability was investigated. Its usefulness was verified by comparing the (Δσ_a)_R-N_f relationship that was obtained from actual Fatigue test results with the (Δσ_a)R-(N_f)_ALP relationship that was derived from accelerated life testing. And the reliability of the predicted life was evaluated. The reliability of the accelerated life-prediction on the base of actual test data was analyzed to be 80% for the plug-type gas-welded joints and 95% for the ring-type gas-welded joints.
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Reliability assessment and prediction of a Fatigue Design Criterion for the gas-welded joints †
Journal of Mechanical Science and Technology, 2010Co-Authors: Seung Yeb BaekAbstract:Gas metal arc welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle structures. However, since the Fatigue strength of the joints welded by gas metal arc welding is considerably lower than that of the parent material due to stress concentration and metallurgical changes at the weld, the Fatigue-strength assessment of welded joints is very important for the reliability and durability of railroad cars and the establishment of a Criterion for long-life Fatigue Design. In this paper, in order to save time and cost for the Fatigue Design, an accelerated life-prediction method that is based on the theory of statistical reliability was investigated. Its usefulness was verified by comparing the (Δσa)R-Nf relationship that was obtained from actual Fatigue test results with the (Δσa)R-(Nf)ALP relationship that was derived from accelerated life testing. And the reliability of the predicted life was evaluated. The reliability of the accelerated life-prediction on the base of actual test data was analyzed to be 80% for the plug-type gas-welded joints and 95% for the ring-type gas-welded joints.
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A Study on Fatigue Design of CT-Type Spot Welded Lap Joint
Journal of the Korean Welding and Joining Society, 2010Co-Authors: Seung Yeb BaekAbstract:Abstract Stress distribution and deformation on the CT-type(Cross Tension type) spot welded lap joint subjected to out of plane tensile load were investigated by finite element method. Using the maximum principal stresses at the nugget edge obtained by FEM analysis, evaluated the Fatigue strength of the CT-type spot welded lap joints having various dimensions and materials. and also, the influence of the geometrical parameters of CT-type spot welded lap joints on stress distribution and Fatigue strength must be evaluated. thus, in this paper, ΔP-N f curve were obtained by Fatigue tests. Using these results, ΔP-N f curve were systematically rearranged in the Δσ-N f relation with the hot spot stresses at the CT-type spot welded lab joints. It was found that the proposed Δσ-N f relation could provide a more reasonable Fatigue Design Criterion for the CT-type spot welded lap joints. Key Words : Tensile shear load, Spot welding, Nugget, Stress concentration, Fatigue strength, Maximum stress
S. K. Park - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Design approach for the spot-welded T-type member using a simulated single spot-welded joint
International Journal of Automotive Technology, 2008Co-Authors: D. H. Bae, Gaehang Lee, S. K. ParkAbstract:In order to develop a Fatigue Design method for actual railroad car and commercial vehicle body structures using the Fatigue data of simulated single spot-welded lap joints, we first analyzed the stress distribution and evaluated Fatigue strength of spot-welded T-type members that are the components of actual railroad car and commercial vehicle body structures. Next, Fatigue Design approach of these members using the Fatigue data of single spot-welded lap joints was investigated. From our results, we found that, even though there was a quantitative difference of Fatigue strength between the single spot-welded joint and the actual members over the same number of Fatigue cycles, through the use of appropriate correction, the Fatigue Design Criterion of actual spot-welded members, such as those used in railroad car and commercial vehicle body, can be predicted using the Fatigue strength of single spot-welded joint.
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Fatigue Design of the Railroad Car Body Member Using a Simulated Single Spot Welded Joint
Key Engineering Materials, 2007Co-Authors: S. K. ParkAbstract:In order to develop a Fatigue Design method for the actual railroad car body structures using the Fatigue data on simulated single spot welded lap joints, firstly, evaluated Fatigue strength on the spot welded t-type member which is a component of the actual railroad car body structure. And next, possibility of Fatigue Design for spot welded T-type member using the Fatigue data of single spot welded lap joints was investigated. From the results, it was found that, even though there is some difference in Fatigue strength between single spot welded joint and the actual members under the same Fatigue life, the Fatigue Design Criterion could be predicted by correction between them.
Won Wook Jung - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Design Criterion of lcv leaf spring based on road load response analysis
Key Engineering Materials, 2005Co-Authors: Ilseon Sohn, Wonseok Jung, Won Wook JungAbstract:Suspension system of light commercial vehicle (LCV) has enough endurance to protect passenger and freight. Leaf spring is major part of LCV suspension system. Thus, Fatigue strength evaluation of leaf spring based on road load response was carried out. At first, the strain of leaf spring was measured on the city mode driving condition and proving ground driving condition. And , the damage analysis of road load response was carried out. After that, Fatigue test of leaf spring was also carried out. Based on e-N life relation, Fatigue life of leaf spring was evaluated at Belgian mode, city mode and drawing test specification called the 3 steps test mode. Next, it is compared the Design life of leaf spring and evaluated Fatigue life by the 3steps test mode. From the above, new target of Belgian mode and city mode was proposed to gratify Design specification of leaf spring. It is expect that the proposed target can be satisfied leaf spring Fatigue endurance at specific road condition.
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The Influence of Residual Stresses by Shot Peening on Fatigue Strength of the Automobile's Coil Spring
Key Engineering Materials, 2005Co-Authors: Wonseok Jung, Soon-cheol Park, Won Wook JungAbstract:Durability assessment for the suspension system of the vehicle is very important. Particularly, corrosion Fatigue strength of coil spring depends on many factors including mechanical and environmental properties. In this paper, residual stresses by multiple shot peening were analyzed using finite element analysis, and evaluated its effect on corrosion Fatigue strength. And also, a corrosion Fatigue Design Criterion for coil spring of light commercial vehicle (LCV) based on proving ground response was proposed.
