The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Ahmet Akkus - One of the best experts on this subject based on the ideXlab platform.
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effect of welding Nugget Diameter on the fatigue strength of the resistance spot welded joints of different steel sheets
Journal of Materials Processing Technology, 2006Co-Authors: Murat Vural, Ahmet Akkus, B EryurekAbstract:Abstract This paper presents an experimental study on the fatigue strength of resistance spot welded galvanized steel sheets and austenitic stainless steel (AISI 304) sheets. The sheet materials were joined by using resistance spot welding as a lap joint. Material combination and Nugget Diameter were selected as experimental parameters. The high cycle fatigue tests were performed and S – N curves were obtained for each specimen. The results show that galvanized steel sheet combination has the highest fatigue limit. The sheet combination which has the minimum fatigue limit is galvanized–AISI 304 sheet combination. For austenitic stainless steel–galvanized steel sheet joint, the measurements of the Nugget Diameter and crack length were performed after fatigue tests. Crack growth rate of the spot welded galvanized–AISI 304 joining type is slower than that of base metals given in literature. C and m coefficients of Paris–Erdogan equation for spot welded AISI 304–galvanized steel sheet joints were obtained.
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on the resistance spot weldability of galvanized interstitial free steel sheets with austenitic stainless steel sheets
Journal of Materials Processing Technology, 2004Co-Authors: Mert Vural, Ahmet AkkusAbstract:Abstract This paper presents an experimental study on the resistance spot weldability of galvanized Interstitial Free (cold formable) steel sheets with austenitic stainless steel sheets. Galvanized IF and austenitic stainless steel sheets were joined by using resistance spot welding as lap joint. Firstly, the variation of the Nugget Diameter according to welding current was investigated. Tensile-shear tests were applied to the welded specimens Also, the form and Diameter of the Nuggets were investigated as macroscopically. The effect of the welding parameters on the microhardness distribution was investigated. The high cycle fatigue tests were performed each welded specimens and S–N curves for each specimens were obtained. The results were discussed and plotted as graphs and figures.
B Eryurek - One of the best experts on this subject based on the ideXlab platform.
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effect of welding Nugget Diameter on the fatigue strength of the resistance spot welded joints of different steel sheets
Journal of Materials Processing Technology, 2006Co-Authors: Murat Vural, Ahmet Akkus, B EryurekAbstract:Abstract This paper presents an experimental study on the fatigue strength of resistance spot welded galvanized steel sheets and austenitic stainless steel (AISI 304) sheets. The sheet materials were joined by using resistance spot welding as a lap joint. Material combination and Nugget Diameter were selected as experimental parameters. The high cycle fatigue tests were performed and S – N curves were obtained for each specimen. The results show that galvanized steel sheet combination has the highest fatigue limit. The sheet combination which has the minimum fatigue limit is galvanized–AISI 304 sheet combination. For austenitic stainless steel–galvanized steel sheet joint, the measurements of the Nugget Diameter and crack length were performed after fatigue tests. Crack growth rate of the spot welded galvanized–AISI 304 joining type is slower than that of base metals given in literature. C and m coefficients of Paris–Erdogan equation for spot welded AISI 304–galvanized steel sheet joints were obtained.
Mert Vural - One of the best experts on this subject based on the ideXlab platform.
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on the resistance spot weldability of galvanized interstitial free steel sheets with austenitic stainless steel sheets
Journal of Materials Processing Technology, 2004Co-Authors: Mert Vural, Ahme AkkusAbstract:This paper presents an experimental study on the resistance spot weldability of galvanized Interstitial Free (cold formable) steel sheets with austenitic stainless steel sheets. Galvanized IF and austenitic stainless steel sheets were joined by using resistance spot welding as lap joint. Firstly, the variation of the Nugget Diameter according to welding current was investigated. Tensile-shear tests were applied to the welded specimens Also, the form and Diameter of the Nuggets were investigated as macroscopically. The effect of the welding parameters on the microhardness distribution was investigated. The high cycle fatigue tests were performed each welded specimens and S–N curves for each specimens were obtained. The results were discussed and plotted as graphs and figures. © 2004 Elsevier B.V. All rights reserved.
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on the resistance spot weldability of galvanized interstitial free steel sheets with austenitic stainless steel sheets
Journal of Materials Processing Technology, 2004Co-Authors: Mert Vural, Ahmet AkkusAbstract:Abstract This paper presents an experimental study on the resistance spot weldability of galvanized Interstitial Free (cold formable) steel sheets with austenitic stainless steel sheets. Galvanized IF and austenitic stainless steel sheets were joined by using resistance spot welding as lap joint. Firstly, the variation of the Nugget Diameter according to welding current was investigated. Tensile-shear tests were applied to the welded specimens Also, the form and Diameter of the Nuggets were investigated as macroscopically. The effect of the welding parameters on the microhardness distribution was investigated. The high cycle fatigue tests were performed each welded specimens and S–N curves for each specimens were obtained. The results were discussed and plotted as graphs and figures.
Kang Zhou - One of the best experts on this subject based on the ideXlab platform.
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study on effect of electrode force on resistance spot welding process
Journal of Applied Physics, 2014Co-Authors: Kang ZhouAbstract:This paper deals with the effect of electrode force on resistance spot welding process. As one of the most important parameters during the process, the electrode force can influence the process in different aspects. Dynamic resistance, which can reflect the internal physical variation of the workpiece, is employed to monitor the characteristic variation of the workpieces. According to theoretical analysis, large electrode force may easily induce surface expulsion. Also, it can decrease the overall dynamic resistance values and postpone the time when first melting point appears, as well as enlarge the duration between times when first melting point and peak value appear. Larger electrode force induces the initial smaller Nugget Diameter, and then the Nugget Diameter has a higher growth speed. However, the overall Nugget Diameter may be smaller and its growth terminates earlier than when smaller electrode force is applied. Final experiments validated all the theoretical analysis.
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online Nugget Diameter control system for resistance spot welding
The International Journal of Advanced Manufacturing Technology, 2013Co-Authors: Kang Zhou, Lilong CaiAbstract:The aim of this paper is to provide an integrated real-time control system for resistance spot welding (RSW), which is capable of producing welds with predetermined Nugget Diameters. Nugget Diameter is a commonly used criterion for estimating the weld quality; thus, the system can be used for online quality control of RSW. The proposed system consists of two parts: a constant current controller and an online Nugget Diameter estimator. The constant current controller is used to guarantee the consistency of the Nugget formation and growth during the welding process, while the online Nugget Diameter estimator can be used as a sensor for online estimation of the Nugget Diameter. The proposed online Nugget Diameter estimator is a mathematical function of the heat energy absorbed by the weld, which is taken into account only after the time when the first melting point of a weld appears. This time can be obtained by means of the dynamic resistance curve with a high resolution. A mathematical model of the online Nugget Diameter estimator is proposed and realized based on the experiment results and mathematical analysis. The welding process would be terminated when the difference between the actual Nugget Diameter and the predetermined desired value is within a given tolerance. According to a series of experiments, the welds used in the experiments had Nugget Diameters, which were well within the limits and the errors were within the given tolerance.
Yung-li Lee - One of the best experts on this subject based on the ideXlab platform.
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evaluation of multiaxial spot weld fatigue parameters for proportional loading
International Journal of Fatigue, 2000Co-Authors: Hong Tae Kang, Mark E Barkey, Yung-li LeeAbstract:Abstract The authors have conducted set of experiments to study the effects of combined tension and shear loads on the fatigue life of spot welded joints. The fatigue life of the specimens depended on the applied load amplitude, the ratio of shear to normal loading, and spot weld Nugget Diameter. The lower load amplitudes had longer fatigue lives, as did the cases which contained a higher amount of shear loading and specimens with a larger Nugget Diameter. Based on the test results, Swellam and co-workers' model, Sheppard's model, Rupp and co-workers' model, and an interpolation/extrapolation model are evaluated. The four approaches were correlated with the experimental fatigue life for the multiaxial test results with reasonable accuracy. The success of Swellam and co-workers' method relies heavily on determining the appropriate parameters β and b 0 . Sheppard's structural stress method agreed reasonably well for mutiaxial test results, although the maximum structural stress range is sensitive to the variation of the sheet thickness, and the determination of Δ M * is a complex procedure. Rupp and co-workers' method is suitable for application to large structural models because mesh refinement is not necessary for modeling the spot weld connection.
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Ultimate Strength of Resistance Spot Welds Subjected to Combined Tension and Shear
Journal of Testing and Evaluation, 1998Co-Authors: Yung-li Lee, T. J. Wehner, T. W. Morrissett, Eric PakalninsAbstract:A new test setup and data concerning the ultimate strength behavior of resistance spot welds in a mild strength steel subjected to combined tension and shear loads are presented. A test plan based on a design of experiments (DOE) with three design factors (coupon width, coupon length, and Nugget Diameter) was conducted to investigate the influence of the factors on the ultimate strength of the resistance spot welds under different loading angles. In this program, test loads were monotonically applied to the resistance spot weld at a specific angle until the load carrying capacity of the resistance spot weld was exceeded. It was found that the Nugget Diameter contributes the most (more than 70%) to the total variation of the recorded ultimate strength and that the coupon length has little effect. A deterministic ultimate strength model was proposed to take into account the interaction of in-plane shear and 90° out-of-plane tensile loading in the resistance spot weld. A reliability model was also demonstrated to evaluate the ultimate strength of a single resistance spot weld.
