Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
MATSUDA Kazuki Last modified date:2024.03.04

Associate Professor / Department of Marine Systems Engineering / Faculty of Engineering


Papers
1. Kazuki Matsuda, Tsukasa Shimoka, Koji Murakami, Tomoya Uchimura, Koji Gotoh, Cyclic true stress true strain relation in the large strain region of common steel for welded structures, Welding International, https://doi.org/10.1080/09507116.2023.2282231, 38, 3, 239-248, 2023.11, [URL], Cyclic true stress - true strain curves were obtained using general-purpose shipbuilding steel in the large strain region. Test methods are incremental step test and static tensile test after cyclic loading. The stress–strain curves for static and cyclic loading were compared to investigate the cause of the difference between each other. A simple method for estimating the cyclic stress-strain curves was proposed. The diameter and curvature of the smallest cross-section of the specimen were measured using telecentric measurement device, and the true stress - true strain curve was obtained using the Bridgman correction method. Using the measurement method, cyclic stress-strain diagrams were obtained in the region where the true strain exceeded 1% by performing cyclic tensile tests using the incremental step method and static tensile tests after cyclic loading. The influence of the test method and maximum displacement conditions on the cyclic stress-strain curve was small within the scope of this study. There was little difference in the elongation between the static tensile test and the static tensile test after cyclic loading. The difference in yield stress between static and cyclic loading was discussed in terms of macro-yield mechanisms at intergranular and transgranular. A simple method for estimating cyclic stress-strain curves from a static stress-strain curve was proposed. The specimens used in this study are general-purpose shipbuilding steels, and the results should be applicable to similar steels for welding and structures..
2. Kazuki MATSUDA, Tsukasa SHIMOKA, Koji MURAKAMI, Tomoya UCHIMURA, Koji GOTOH, Cyclic true stress true strain relation in the large strain region of common steel for welded structures, QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2023, Volume 41, Issue 3, Pages 217-224. Cyclic true stress - true strain curves were obtained using general-purpose shipbuilding steel in the large strain region. Test methods are incremental step test and static tensile test after cyclic loading. The stress-strain curves for static and cyclic loading were compared to investigate the cause of the difference between each other. A simple method for estimating the cyclic stress-strain curves was proposed. The diameter and curvature of the smallest cross-section of the specimen were measured using telecentric measurement device, and the true stress - true strain curve was obtained using the Bridgman correction method. Using the measurement method, cyclic stress-strain diagrams were obtained in the region where the true strain exceeded 1% by performing cyclic tensile tests using the incremental step method and static tensile tests after cyclic loading. The influence of the test method and maximum displacement conditions on the cyclic stress-strain curve was small within the scope of this study. There was little difference in the elongation between the static tensile test and the static tensile test after cyclic loading. The difference in yield stress between static and cyclic loading was discussed in terms of macro-yield mechanisms at intergranular and transgranular. A simple method for estimating cyclic stress-strain curves from a static stress-strain curve was proposed. The specimens used in this study are general-purpose shipbuilding steels, and the results should be applicable to similar steels for welding and structures., [URL].
3. Tohru Okada, Hideki Ueda, Kazuki Matsuda, Yasunobu Miyazaki, Masanori Yasuyama, Hidetoshi Fujii, Effect of strength of steel sheets on tensile shear strength and failure mode of dissimilar joint of spot welds, Welding International, https://doi.org/10.1080/09507116.2023.2202949, 37, 5, 282-294, 2023.05, [URL], Advanced high strength steel sheet (AHSS) is widely used in the automotive body for weight reduction and the improvement of crash performance. For example, TS1500 MPa class hot stamped steel (1500HS steel) sheet is applied to many vehicle models. However, there is a concern that performance of spot welded joints will decline as steel strength increases. In order to further expand the application of AHSS, it is very important to have knowledge about the characteristics of spot welded joints. In this report, we investigated the tensile shear strength (TSS) of the 1500HS steel sheet. Then, we compared the joint strength and failure position of the same kind material joints and the dissimilar material joints with the 1500HS steel sheet in case of the plug failure. As a result, it was found that TSS of dissimilar material joints depend on base metal strength on lower strength steel side. However, fracture occurred on the 1500HS steel side except for joints with large difference of base metal strength. The mechanism is thought that the effect of strain concentration at the edge of nugget on the 1500HS steel side due to the increase of rotational deformation around the nugget..
4. Kazuki Matsuda, Yoshinari Ishida, Shinji Kodama, Fatigue strength improvement method for thin sheet GMA welding joints by weaving, Welding in the World, https://doi.org/10.1007/s40194-023-01480-z, 67, 733-739, 2023.01, [URL], A method for improving the fatigue strength of thin steel sheet gas metal arc (GMA)-welded joints using weaving welding was evaluated. Weaving created peaks and valleys at the weld toe. The valley has high stress triaxiality, and plastic deformation is unlikely to occur. Fatigue cracks occurred from the peaks with gentle toe shapes. Therefore, it is considered that the fatigue strength is improved by reducing the initiation points of the crack and stress concentration at the toe. The fatigue test results showed that the fatigue limit of the weaving welding joint was improved compared with that of the normal welding joint. Furthermore, the optimal weaving condition, which is the relationship between the weaving wavelength and torch swing amplitude, was evaluated. As a consequence, when the wave density is small, the crack initiation point is not restricted to the peak. On the other hand, when the wave density is large, the peak and valley shapes merge and the weaving effect disappears. In addition, undercuts occurred when the swing amplitude became too large. The mechanism of improving the fatigue strength was considered by observing the initiation point of the fatigue microcracks..
5. Tohru OKADA, Hideki UEDA, Kazuki MATSUDA, Yasunobu MIYAZAKI, Masanori YASUYAMA, Hidetoshi FUJII, Effect of strength of steel sheets on tensile shear strength and failure mode of dissimilar joint of spot welds, QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2022 Volume 40 Issue 4 Pages 216-225. Advanced high strength steel sheet (AHSS) is widely used in the automotive body for weight reduction and the improvement of crash performance. In general, weldability and formability of steel sheet tends to decline as steel strength increases. Hot stamping is a technique that achieves both formability and strength of steel sheet, and TS1500MPa class hot stamped steel sheet is applied to many vehicle models. On the other hand, since the joint strength characteristics of the spot weld are dominated by the melt-solidified zone and weld heat affected zone, there is a concern that performance of spot welded joints will decline as steel strength increases. In other words, in order to further expand the application of AHSS, it is very important to have knowledge about the characteristics of spot welded joints. In this report, we investigated the TSS of the TS1500MPa class hot stamped steel sheet, focusing on the characteristics of tensile shear joints. Then, we compared the joint strength and failure position of the same kind material joints and the dissimilar material joints with the TS1500MPa class hot stamped steel sheet in case of the plug failure. As a result, it was found that TSS of dissimilar material joints depend on base metal strength on lower strength steel side. However, fracture occurred on the TS1500MPa class hot stamped steel side except for joints with large difference of base metal strength. The mechanism is thought that the effect of strain concentration at the edge of nugget on the TS1500MPa class hot stamped steel side due to the increase of rotational deformation around the nugget., [URL].
6. Kazuki Matsuda, Takayuki Yonezawa, Investigation of fatigue strength of root of lap fillet welds of thin sheet and improvement method, Theoretical and Applied Fracture Mechanics, https://doi.org/10.1016/j.tafmec.2022.103667, 122, 103667, 2022.11, [URL], This study investigates the dominant factors of fatigue strength at the root of thin-sheet lap fillet arc welds, which are frequently used in automobile chassis components. A method to improve the root fatigue strength was investigated. The direction of fatigue crack propagation at the root coincided with the direction of maximum circumferential stress range. The circumferential stress was reduced by increasing the distance from the toe to the root (penetration width). Fatigue strength originating from the root was improved in welded joints where the penetration width was increased by adjusting the welding aim point and heat input..
7. Tsukasa Shimooka, Koji Murakami, Kazuki Matsuda and Koji Gotoh, Experimental Investigation on Stress-Strain Relationship of Steel under Cyclic Loading, Proceedings of Japan Welding Society, Kyushu-chapter,No. 19 (2022), 1-4..
8. Kazuyuki Teratsuji, Tomoya Uchimura, Kazuki Matsuda and Koji Gotoh, Basic Study on Grain Refinement by Laser Irradiation for Fatigue Strength Improvement, Proceedings of Japan Welding Society, Kyushu-chapter,No. 19 (2022), 37-40..
9. Yong-Yi Feng, Norihiro Watanabe, Kento Yamazaki, Kazuki Matsuda, Koji Gotoh, A Study on Prediction of Fillet Weld Bead Shape Using Machine Learning with Welding Conditions and Welding Noise as Input Variables, Proceedings of Japan Welding Society, Kyushu-chapter,No. 19 (2022), 41-44..
10. Kazuki Matsuda, Shinji Kodama, Effect of the strength of steel sheets and wires on residual stress of thin steel sheet lap-fillet GMA weld joint, Welding International, https://doi.org/10.1080/09507116.2022.2030536, 36, 2, 97-113, 2022.02, [URL], Weld residual stress of the lap fillet GMA welding joints which was performed using two strength grades of steel sheets and two strength grades of welding wires were measured. In addition, to consider the effects of steel sheet strength and weld metal strength on welding residual stress, thermal elastoplastic analysis using FEM was carried out for the experiments. As a result of the analysis using the temperature history of the heat-affected zone as a fitting parameter, the residual stress distributions near the toe were in agreement with the measurement in the FE analysis. Comparing the residual stress distributions in the direction perpendicular to the weld line on the weld metal surface near the toe, which is the occurring point of fatigue cracks in the FE analysis results, with the same steel sheet, the higher the weld metal strength the smaller the tensile residual stress. And comparing with the same wire, the higher the steel sheet strength the higher the tensile residual stress. The reason for the former is that when using high-strength wire, cooling transformation occurs at a lower temperature than using low-strength wire. As a result, it is considered that the tensile residual stress was effectively reduced by causing transformation expansion while the surrounding strength was high. The reason for the latter is considered to be that each stress value changes based on the yield stress of the steel sheet and weld metal because the plastic strain continues to occur in each direction until transformation occurs after welding. It was considered that the larger the ratio of the hardness of the weld metal to the base metal, the smaller the ratio of the residual stress of the weld metal near the toe to the yield stress..
11. Kazuki Matsuda, Shinji Kodama, Effect of galvannealed coating on corona bond strength of resistance spot welding, Science and Technology of Welding and Joining, https://doi.org/10.1080/13621718.2021.2023964, 27, 2, 132-140, 2022.01, [URL], The effect of galvannealed (GA) coating on the corona bond strengths of resistance spot welding joints was investigated. A cross tensile test was performed with removal of the nugget, using GA steel sheets and steel sheets whose coating had been removed via pickling. The maximum load with coating was lower than that without coating. When the nugget diameter was small (3√t, t: sheet thickness), GA coating reduced the corona bond strength (MPa). In contrast, when the nugget diameter was large (5√t), GA coating did not change the corona bond strength but reduced the corona bond area..
12. Kazuki MATSUDA, Shinji KODAMA, Effect of the strength of steel sheets and wires on residual stress of thin steel sheet lap-fillet GMA weld joint, QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2021 Volume 39 Issue 3 Pages 218-231. Weld residual stress of the lap fillet GMA welding joints which was performed using two strength grades of steel sheets and two strength grades of welding wires were measured. In addition, in order to consider the effects of steel sheet strength and weld metal strength on welding residual stress, thermal elastoplastic analysis using FEM was carried out for the experiments. As a result of analysis using the temperature history of the heat-affected zone as a fitting parameter, the residual stress distributions near the toe were in agreement with the measurement in the FE analysis. Comparing the residual stress distributions in the direction perpendicular to the weld line on the weld metal surface near the toe, which is the occurring point of fatigue cracks in the FE analysis results, with the same steel sheet, the higher the weld metal strength the smaller the tensile residual stress. And comparing with the same wire, the higher the steel sheet strength the higher the tensile residual stress. The reason for the former is that when using high-strength wire, cooling transformation occurs at a lower temperature than using low-strength wire. As a results, it is considered that the tensile residual stress was effectively reduced by causing transformation expansion due to while the surrounding strength was high. The reason for the latter is considered to be that the each stress value changes based on the yield stress of the steel sheet and weld metal because the plastic strain continues to occur in each direction until transformation occurs after welding. It was considered that the larger the ratio of the hardness of the weld metal to the base metal, the smaller the ratio of the residual stress of the weld metal near the toe to the yield stress., [URL].
13. Kazuki MATSUDA, Shinji KODAMA, Effect of the strength of steel sheet and wire on residual stress of thin sheet arc weld, Preprints of the National Meeting of JWS, 109, Pages 230-231, September 21 - 28, 2021., [URL].
14. Kazuki Matsuda, Shinji Kodama, Observation of fatigue microcracks and estimation of fatigue strength of a thin sheet arc welded part considering micro-ripples, International Journal of Fatigue, https://doi.org/10.1016/j.ijfatigue.2020.106087, 145, 2021.04, [URL], Fatigue tests were conducted on a thin sheet arc welded part using two types of welding wires. Microscopic observations of specimens tested at the fatigue limit stress revealed that microcracks were initiated in the micro-ripples on the weld metal surface. Furthermore, a coarse ferrite structure often contains existing microcracks. A method for quantitatively evaluating the effects of microscopic irregularities on the weld metal surface and macroscopic toe shape on the fatigue strength is proposed. It was found that microscopic irregularities on weld metal have a significant impact on the fatigue limit, depending on their metallurgical structure..
15. Kazuki MATSUDA, Shinji KODAMA, Observation of Micro Fatigue Cracks at Arc Welded Joint of Thin Steel Sheet (Report 2), Preprints of the National Meeting of JWS, Pages 164-165, September 09 - 11, 2020., [URL].
16. Kazuki MATSUDA, Shinji KODAMA, Observation of Micro Fatigue Cracks at GMA Welded Joint of Thin Steel Sheet, QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2020 Volume 38 Issue 3 Pages 157-163. Fatigue tests were performed on GMA welded joints using a prototype steel sheets with varying amounts of C. In addition, the origin of the fatigue cracks in the thin steel GMA welded joints were investigated through observation the micro cracks in the specimens that were judged to be not fractured by fatigue limit stress in the fatigue test. As a result of plane bending fatigue test of bead-on-plate welding sheet, fatigue limit of the welded specimen did not differ much between the steel sheets. Observing the specimens which were not fractured at the fatigue limit, micro cracks often occurred at the bottom of the ripples on the weld metal surface and in the ferrite structure. It was founded that fatigue cracks in thin steel sheet GMA welding using mixed gas occurred parallel along the bottom of the ripples and parallel cracks merged with the crack growth, resulting in a zigzag propagation path on the weld joint surface. The effect of ripple on the fatigue limit was predicted by comparing estimating the fatigue limit without considering the ripple with the fatigue limit obtained from experiment. Finally, the effect of ripple on the fatigue limit was more than 10% and less than 20%. And it was implied that higher the strength of the material, the greater the effect of ripple on the fatigue limit., [URL].
17. Kazuki MATSUDA, Shinji KODAMA, Stress analysis of lap fillet joint using thin steel sheet, Preprints of the National Meeting of JWS, Pages 226-227, 2019, [URL].
18. Kazuki Matsuda, Shinji Kodama, Evaluation of corona bond strength of resistance spot welding, Science and Technology of Welding and Joining, https://doi.org/10.1080/13621718.2019.1613010, 25, 1, 66-72, 2019.05, [URL], A simple method to evaluate the strength of corona bond of resistance spot welding is proposed and verified by removing the nugget of welded specimen before conducting a cross tension test. The strength of the corona bond is evaluated using thin steel sheets of different strengths. The result indicates that the higher the strength of the steel sheet, the higher the strength of the corona bond. A tensile test of the corona bond part is conducted using the small tensile test technique to verify the corona bond strength. A comparison of the stress value at the same strain (1%) indicates that the stress of the small tensile test is in the order of the strength of the steel sheet..
19. Kazuki MATSUDA, Shinji KODAMA, Evaluation of Corona Bond Area Strength of Resistance Spot Welding, International Symposium on Joining Technologies in Advanced Automobile Assembly 2018, 41-42, 2018.11.
20. Kazuki Matsuda, Shinji Kodama, Evaluation of Corona Bond Area Strength of Resistance Spot Welding, Preprints of the National Meeting of JWS, Pages 240-241, 2018., [URL].
21. Kazuki Matsuda, Yoshinari Ishida, Shinji Kodama, Observation of Micro Cracks at Arc Welded Steel Sheet, Preprints of the National Meeting of JWS, Pages 18-19, 2017., [URL].
22. Kazuki Matsuda, Yoshinari Ishida, Shinji Kodama, Yasunobu Miyazaki, Evaluation of Fatigue Crack Propagation Properties of Thin Steel Plate welds, Preprints of the National Meeting of JWS, Pages 368-369, 2016., [URL].
23. Kazuki Matsuda, Koji Gotoh, A Study of Replacing Method to the Single-Frequency Stress History to the Superimposed Stress History with Multiple Frequency Components, Conference Proceedings The Japan Society of Naval Architects and Ocean Engineers, Pages 489-492, 2015., [URL].
24. Kazuki Matsuda, Koji Gotoh, Numerical simulation of fatigue crack propagation under superimposed stress histories containing different frequency components with several mean stress conditions, Marine Structures, https://doi.org/10.1016/j.marstruc.2014.12.005, 41, 77-95, 2015.04, [URL], Fatigue crack propagation behavior under superimposed stress histories containing different frequency components with several mean stress conditions was investigated. Numerical simulation of fatigue crack propagation based on an advanced fracture mechanics approach using the RPG (Re-tensile Plastic zone Generating) stress criterion for fatigue crack propagation was improved to extract the effective part from the applied stress history for fatigue crack propagation. The parameter, which is based on the plastic hysteresis energy consumed in the vicinity of a crack tip, was applied and implemented into the numerical simulation code of fatigue crack propagation. Fatigue crack propagation tests under various superimposed stress conditions with several mean stress conditions were performed and compared with the fatigue crack propagation histories obtained from the improved numerical simulations. These comparisons show the validity of the proposed procedure for extracting the effective stress history from the superimposed stress histories with different frequency components and mean stresses. Additionally, practical fatigue strength evaluations based on the linear cumulative fatigue damage parameter were conducted to investigate the tendency of the fatigue damage value under these stress conditions..
25. Kazuki Matsuda, Koji Murakami, Koji Gotoh, Numerical Simulation of Fatigue Crack Propagation under Superimposed Stress Histories with Several Constant and Variable Mean Stresses, Journal of the Japan Society of Naval Architects and Ocean Engineers, 2014 Volume 20 Pages 119-125. Fatigue crack propagation behavior under superimposed loading histories with several mean stress conditions is highlighted.Numerical simulation of fatigue crack propagation based on an advanced fracture mechanics approach using the RPG (Re-tensile Plastic zone Generating) stress criterion for fatigue crack propagation is improved to enable the extraction of the effective loading history for fatigue crack propagation. The parameter, which is based on the plastic hysteresis consuming in the vicinity of a crack tip,is applied to extract the effective loading for fatigue crack propagation and implemented into the numerical simulation code of fatigue crack propagation. Fatigue crack propagation tests under various superimposed loading conditions, which contain several constants and variable mean stress, are performed and comparison of fatigue crack propagation histories obtained from the improved numerical simulations with the measurements is performed. These comparisons show the validity of the proposed procedure for extracting the effective loading history from the superimposed loading histories with different frequencies. Subsequently, practical fatigue strength evaluation based on the linear cumulative fatigue damage parameter were conducted to investigate the tendency of fatigue damage value affected by mean stresses., [URL].
26. Koji Gotoh, Kazuki Matsuda, Numerical Simulation of Fatigue Crack Propagation under Variable Amplitude Loading Containing Two Different Frequency Components, Journal of the Japan Society of Naval Architects and Ocean Engineers, 2013 Volume 17 Pages 75-81. Fatigue crack propagation behaviour under superposed loading histories which contain two different frequency components is highlighted. Numerical simulation of fatigue crack propagation based on an advanced fracture mechanics approach using the RPG (Retensile Plastic zone Generating) stress criterion for fatigue crack propagation is improved to enable the extraction of the effective loading history. The critical value of the plastic hysteresis for the stress versus strain relationship occurring in the vicinity of a crack tip is defined as the control parameter for extracting the effective loading history. Comparison of fatigue crack propagation curves obtained from the improved numerical simulations with the measurements under the superposed loading histories is performed. These comparisons show the validity of the proposed procedure for extracting the effective loading history from the superposed loading history containing different frequencies. Besides, the insufficiency of S-N curves approach with the cumulative damage law for the superposed loading history condition containing different frequency components is conducted., [URL].
27. Kazuki Matsuda, Koji Gotoh, Numerical Simulation of Fatigue Crack Propagation Under Simulated Whipping Loading Arising in Hull Structures, Volume 3: Materials Technology; Ocean Space Utilization, ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering (OMAE2013),, https://doi.org/10.1115/OMAE2013-10985, 3, 2013.06, [URL], Fatigue crack propagation behavior under simulated whipping loadings which contain two different frequency components is highlighted. Numerical simulation of fatigue crack propagation based on an advanced fracture mechanics approach using the RPG (Re-tensile Plastic zone Generating) stress criterion for fatigue crack propagation is improved to enable the extraction of the effective loading history. The critical value of the plastic hysteresis for the stress versus strain relationship occurring in the vicinity of a crack tip is defined as the control parameter for extracting the effective loading history. Comparison of fatigue crack propagation curves obtained from the improved numerical simulations with the measurements which were conducted by Sumi (2010) is performed. These comparisons show the validity of the proposed procedure for extracting the effective loading history from the superposed loading history containing different frequencies. In addition, imperfection of the S-N curves approach, which corresponds to the combination of the linear cumulative damage law and the loading cycle count by the rain flow method, is conducted..
28. Koji GOTOH,Kazuki MATSUDA,O KITAMURA, Numerical simulation of fatigue crack propagation under superposed loading histories with two different frequencies, HYDROELASTICITY 2012, 287-297, 2012.09.