Faculty Profiles - HANJI Takeshi

Papers - HANJI Takeshi

Division display 81 - 100 of about 245 ／ All the affair displays >>

Fatigue strength of transverse attachment steel joints with single-sided arc weld using low transformation temperature welding consumable Reviewed

Takeshi Hanji, Kazuo Tateishi, Suguru Kano, Masaru Shimizu, Tadahisa Tsuyama, Toshio Takebuchi

Welding in the World Vol. 64 ( 7 ) page： 1293–1301 2020.7

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

This study investigated the applicability of low transformation temperature (LTT) arc welding consumables to improve fatigue strength against weld root failure. Transverse attachment joints formed by single-sided welding, similar to rib-to-deck connections in orthotropic steel bridge decks, were fabricated using an LTT welding consumable and conventional welding consumable. Fatigue tests were performed with out-of-plane bending loads using a vibration-type fatigue testing machine. The test results indicated that higher fatigue strength can be achieved in the joint with an LTT consumable compared with a conventional one. In addition, residual stresses around the weld bead were clarified by X-ray diffraction measurements and finite element analyses. The results revealed that the LTT consumable weld metal can reduce residual stress around the weld and also introduce compressive residual stress to the weld root, which can contribute to improved fatigue strength.

DOI： 10.1007/s40194-020-00915-1

Extremely low cycle fatigue assessment model for structural steel and its application to welded joints Reviewed

Takeshi Hanji, Kazuo Tateishi

Proceedings of the VAL4 page： CD-ROM 2020.7

Authorship：Lead author Language：English

The accuracy of Miner's rule has not been verified in an extremely large strain field, corresponding to the fatigue life of less than tens cycles. In this study, low cycle fatigue tests under variable strain amplitude in the extremely large strain field were conducted with a newly developed testing system. The result revealed that the Miner's rule always predicted a longer fatigue life than the observed life. Therefore, this study proposed a simple fatigue assessment model introducing the damage mechanics concept and examined its validity as another method for predicting low cycle fatigue life.

Fatigue strength of welded joints in steel-concrete composite slab using L-shaped shear connectors Reviewed

Takeshi Hanji, Kazuo Tateishi, Masaru Shimizu, Koichi Asano, Takaaki Ishii, Kiyoshi Kobayashi, Daisuke Uchida

Journal of Structural Mechanics and Earthquake Engineering, JSCE (Journal of Hybrid Structures) Vol. 76 ( 5 ) page： II_50-II_61 2020.5

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

In this study, the fatigue strength of welded joints in steel-concrete composite slabs was investigated by fatigue testing. In addition, the local stress around the welded joint was evaluated through finite element analysis. In the test, fatigue cracks occurred at the toes of boxing welds of L-shaped shear connectors as a result of stress concentration due to the local out-of-plane bending deformation of the steel plates around the boxing weld. This local deformation can be produced by the steel and concrete behaving in-dependent of one another locally near welds when the bond at their interface is lost. The test results demonstrated that the fatigue assessment of welded joints in a composite slab can be performed using the hot-spot stress approach. Then, actual composite slabs with different structural characteristics were analyzed to investigate the local stress behavior around welded joints, and their fatigue performance was assessed based on the hot-spot stress approach.

DOI： 10.2208/jscejseee.76.5_II_50

Fatigue strength of friction type high strength bolted joints with compact bolt spacing and edge distance Reviewed

Shogo Kiyokawa, Kazuo Tateishi, Takeshi Hanji, Masaru Shimizu

Journal of Structural Mechanics and Earthquake Engineering, JSCE Vol. 76 ( 2 ) page： 212-222 2020.5

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

Damaged steel bridge members are often repaired by patching steel plates with high strength bolts. Sometimes, due to spatial restriction, there is a need to be shorten bolt spacing or edge distance than those specified in a design specification. However, knowledge on fatigue performance of the joints with the compact bolt arrangement is little.
In this study, fatigue strength of friction type bolted joints with compact bolt arrangement was investigated through fatigue tests and finite element analyses. The test result indicated that the compact bolt arrangement, especially a smaller end distance, decrease the fatigue strength of the joints. The analysis results demonstrated that stress concentration occured at the surface around a bolt hole where the fatigue crack initiated in the test. Since the stress concentration was strongly correlated to the fatigue strength in the test, the effects of compact bolt arrangement with a variety of material strengths and joint dimensions were discussed based on the stress concentration.

DOI： 10.2208/jscejseee.76.2_212

Low cycle fatigue evaluation of cruciform welded joints containing incomplete penetration Reviewed

Takeshi Hanji, Yuko Ohashi, Kazuo Tateishi, Masaru Shimizu

Journal of Structural Engineering, JSCE Vol. 66A page： 253-263 2020.3

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

This study examined low cycle fatigue behavior of cruciform welded joints containing incomplete penetration. Six types of specimens with different sizes of weld penetrations and weld leg lengths were tested under cyclic plastic strains. The test results revealed that the fatigue strength and cracking patterns depend on the ratio of the weld penetration to the main plate thickness and the ratio of the weld leg length to the main plate thickness, respectively. Then, elasto-plastic finite element analyses including the effective notch concept were performed. The results indicate that the fatigue strength and cracking pattern of the specimens can be correlated with the local strain distribution around the effective notch.

DOI： 10.11532/structcivil.66A.253

Fatigue strength of weld root in transverse attachment joints with single-sided weld using low transformation temperature welding consumable Reviewed

Takeshi Hanji, Suguru Kano, Kazuo Tateishi, Masaru Shimizu, Tadahisa Tsuyama, Toshio Takebuchi

Journal of Structural Engineering, JSCE Vol. 66A page： 607-616 2020.3

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

This study investigated the applicability of low transformation temperature (LTT) welding consumables to improve fatigue strength against weld root failure. Transverse attachment joints formed by single-sided welding were fabricated using an LTT welding consumable and conventional welding consumable. Fatigue tests with out-of-plane bending loads revealed that higher fatigue strength and fatigue limit can be achieved in the joint with an LTT consumable compared with a conventional one. In addition, residual stresses around the weld bead were clarified by X-ray diffraction measurements and finite element analyses. The results indicated that the LTT consumable can reduce tensile residual stress around the weld and also introduce compressive residual stress to the weld root.

DOI： 10.11532/structcivil.66A.607

Effect of weld penetration on low cycle fatigue strength of load-carrying cruciform joints Reviewed

Takeshi Hanji, Kazuo Tateishi, Yuko Ohashi, Masaru Shimizu

Welding in the World Vol. 64 ( 2 ) page： 327-334 2020.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

This study examined the low-cycle fatigue behavior of load-carrying cruciform-welded joints containing incomplete penetration. Five types of specimens with different sizes of weld penetrations and weld leg lengths were tested under cyclic plastic strains. During testing, cracking behavior was observed on the side surface of the specimen. The test results revealed that the fatigue strength and cracking patterns depend on the ratio of the weld penetration to the main plate thickness and the ratio of the weld leg length to the 5main plate thickness, respectively. Elasto-plastic finite element analyses including the effective notch concept were then performed. The results indicate that the fatigue strength and cracking pattern of the specimens can be correlated with the local strain distribution around the effective notch.

DOI： 10.1007/s40194-019-00834-w

Estimation method for low cycle fatigue of welded joint in shear panel damper Reviewed

Masaru Shimizu, Kazuo Tateishi, Takeshi Hanji, Yasumoto Aoki

Journal of Constructional Steel Vol. 27 page： 741-748 2019.11

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

A shear panel damper can absorb seismic energy by its hysteresis damping. On the other hand, repetition of high strain around its welded joints could lead to low cycle fatigue failure. To avoid the low cycle fatigue, a simple assessment method was investigated in this study. The relationship between mean shear strain range and local strain range at a crack initiation point was examined for various shear panel dampers. From the relation, estimation equations for the local strain range at crack initiation point were established. In addition, low cycle fatigue strength curves based on the mean shear strain range were developed. Based on the fatigue strength curve, fatigue crack initiation life was discussed among the several shear panel dampers.

Fatigue strength evaluation on bearing type bolted joint of pultruded CFRP member Reviewed

Masaru Shimizu, Kazuo Tateishi, Takeshi Hanji, Yasuo Kitane, Kai Hiroyama

Proceedings of the 13th Symposium on Research and Application of Hybrid and Composite Structures page： 430-437 2019.11

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

In recent years, the pultrusion method for manufacturing CFRP member has been established. The environment to stably supply large-scaled CFRP members is being developed. On the other hand, mechanical behavior and fatigue behavior of the bearing type bolted joint used for connection of FRP members is not clearly understood. In this study, tensile fatigue tests on perforated plate and double shear bearing type bolted joint of pultruded CFRP were performed. The perforated plate specimen represents sperior fatigue durability over 10million cycle even under nominal stress range of 260 N/mm2. However, the fatigue crack occurs from the edge of the hole, and propagates to longitudinal direction. As for bearing type bolted joint specimen, local bearing failure was observed around the contact part between bolt and CFRP member. The shear-out failure was also observed when the nominal stress is over 70 N/mm2. Moreover, finite element analysis was performed to examine the stress around the bolt hole. Fatigue durability of pulutruded CFRP member was discussed by arranging fatigue test results with maximum principal strain obtained from the analysis.

Fatigue strength of welded joints in steel-concrete composite slab using angle shape shear connectors Reviewed

Takeshi Hanji, Kazuo Tateishi, Masaru Shimizu, Koichi Asano, Takaaki Ishii, Kiyoshi Kobayashi, Daisuke Uchida

Proceedings of the 13th Symposium on Research and Application of Hybrid and Composite Structures page： 189-198 2019.11

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

In this study, fatigue strength of welded joints in steel-concrete composite slabs was investigated by a fatigue test and finite element analysis. In the test, fatigue cracks occurred at toes of boxing welds of angle-shape shear connectors and propagated into a bottom plate, which were caused by stress concentration due to local out-of-plane bending deformation of steel plates around the boxing weld. This local deformation can be caused because concrete and steel plates locally behave separately near welds when bond between them is lost. The test result demonstrated that fatigue assessment of welded joints in the steel-concrete composite slab can be performed using the structural hot spot stress approach. Then, actual composite slabs with different structural dimensions were analyzed to investigate local stress behavior around welded joints, and their fatigue performance was assessed based on the hot spot stress approach.

A prediction method for fatigue enhancement of drilled crack-arrest holes accompanied by splice plates Reviewed

Takeshi Hanji, Shogo Kiyokawa, Kazuo Tateishi, Masaru Shimizu

Proceedings of the 12th Pacific Structural Steel Conference page： CD-ROM 2019.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The present study examined a prediction method for the strain at drilled fatigue crack-arrest holes covered by splice plates to evaluate fatigue enhancement of the hole accompanied by the splices. Finite element analyses were performed in order to establish a method to predict the strain at a drilled hole from the strain that can be measured on a splice plate. In the present study, axially loaded center-cracked steel plates repaired by adding splice plates were analyzed for various plate thicknesses of both cracked and splice plates, bolt-hole arrangements and diameters, and crack lengths. The strain on the splice around the drilled hole was correlated with the strain at the hole. Based on the results, a prediction formula for the strain at the hole, which is a function of the pitch and diameter of bolt holes near the drilled hole, was proposed. Static tensile loading tests were conducted for several center-cracked plates repaired by adding splice plates in order to verify the proposed strain-prediction method. The test results demonstrated that the strain at the drilled hole can be predicted with enough accuracy based on the strain on the splice.

A proposal on reduction of welding residual stress in rib-to-deck welded joint in orthotropic steel deck Reviewed

Cut Atika Putri, Kazuo Tateishi, Takeshi Hanji, Masaru Shimizu

Proceedings of the 12th Pacific Structural Steel Conference page： CD-ROM 2019.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The presence of tensile residual stress caused by the welding process, at weld root of rib-to-deck joint in Orthotropic Steel Deck (OSD), believed can trigger fatigue crack occurrence although the applied cycle stresses are compression. In this study, a new method to reduce tensile residual stress at the weld root of rib-to-deck joint in OSD is proposed. It was started with simulating the welding process by using Finite Element (FE) analysis. Various structural parameters are considered to examine its sensitivity in the tensile residual stress distribution at the weld root through the deck plate. It was found that high tensile residual stress is generated at the weld root and tend to be increased with the increase of deck plate thickness and welding penetration. The proposed method is simulated after welding analysis. In this method, the plastic deformation is applied around the weld root by external opening force after cutting the bottom part of the through-rib. The tensile residual stress at the weld root was dispersed when expanding the web plate of through-rib. Significant reduction of tensile residual stress can be obtained when the weld bead size is relatively small.

Evaluation of low cycle fatigue crack propagation under various controlled cyclic loading histories Reviewed

Arief Panjaitan, Kazuo Tateishi, Masaru Shimizu, Takeshi Hanji

Proceedings of the 12th Pacific Structural Steel Conference page： CD-ROM 2019.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Low cycle fatigue, is one of the main failure modes in steel structures due to the earthquake. Earthquake acceleration leads to contribute irregular and high plastic deformation to the affected structures. However, the low cycle fatigue durability under irregular loading has not been clarified. The objective of this research is to obtain crack propagation pattern and low cycle fatigue life prediction under various loading histories. Two types of controlled displacement sequences with mixed amplitude were applied to the CT specimen. One was the series with uniform value at constant high and constant low displacement. The remain was the series with changing amplitude from high to low displacement and from low to high displacement. Experimental work and Finite Element (FE) analysis conducted gave ΔJ-integral following applied cyclic loading histories trends and predicted fatigue life curve resulted showed non linear relationship for the crack growth rate during additional value of ΔJ-Integral.

Low cycle fatigue behavior of load-carrying cruciform welded joints with incomplete penetration Reviewed

Yuko Ohashi, Takeshi Hanji, Kazuo Tateishi, Masaru Shimizu

Proceedings of the 12th Pacific Structural Steel Conference page： CD-ROM 2019.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

This study examined low cycle fatigue behavior of load-carrying cruciform welded joints containing incomplete penetration. Six types of specimens with different sizes of weld penetrations and weld leg lengths were tested under cyclic plastic strains. During testing, cracking behavior was observed on the side surface of the specimen. The test results revealed that the fatigue strength and cracking patterns depend on the ratio of the weld penetration to the main plate thickness and the ratio of the weld leg length to the main plate thickness, respectively. Then, elasto-plastic finite element analyses including the effective notch concept were performed. The results indicate that the fatigue strength and cracking pattern of the specimens can be correlated with the local strain distribution around the effective notch.

Fatigue strength of single-sided fillet welded joints with low transformation temperature welding material Reviewed

Suguru Kano, Takeshi Hanji, Kazuo Tateishi, Masaru Shimizu, Tadahisa Tsuyama, Toshio Takebuchi

Proceedings of the 12th Pacific Structural Steel Conference page： CD-ROM 2019.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

This study investigated the applicability of low transformation temperature (LTT) consumables to improve fatigue strength against weld root failure. Transverse attachment joints formed by single-sided welding, similar to rib-to-deck connections in orthotropic steel bridge decks, were fabricated using an LTT welding consumable and conventional welding consumable. Fatigue tests were performed with out-of-plane bending loads using a vibration-type fatigue testing machine. The test results indicated that higher fatigue strength can be achieved in the joint with an LTT consumable compared with a conventional one. In addition, residual stresses around the weld bead were clarified by X-ray diffraction measurements and finite element analyses. The results revealed that the LTT consumable can reduce residual stress around the weld and also introduce compressive residual stress to the weld root, which can contribute to improved fatigue strength.

A study on fatigue crack propagation behavior on steel plate subjected to out of plane bending Reviewed

Kentaro Horio, Kazuo Tateishi, Masaru Shimizu, Takeshi Hanji

Proceedings of the 12th Pacific Structural Steel Conference page： CD-ROM 2019.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Under out-of-plane bending and shearing force, a crack develops in the thickness direction with an inclination toward the axial direction. Typically, three types of crack propagation behaviors can be observed; the crack develops in thickness direction up to the opposite surface, the crack is arrested after inclining toward an axial direction, and a counter crack comes from the opposite surface. In this study, the occurrence condition of each crack propagation behavior was investigated. Cyclic bending fatigue tests were conducted for notched steel plates. Furthermore, the crack propagation and counter crack occurrence were evaluated from finite element analysis. The crack propagation pass tends to be affected by the ratio between bending stress and shear stress near the crack. Also, in the case that the counter crack was generated, the strain on the opposite surface yielded.

Fatigue crack propagation analysis of longitudinal welded joint containing blowholes Reviewed

Cut Atika Putri, Kazuo Tateishi, Takeshi Hanji, Masaru Shimizu

Proceedings of the ISSS 2019 2019.11

Language：English

Fatigue strength of longitudinal welded joints is used to be less focused since the other joints are considered more critical. However, the presence of blowholes in the fillet welds can be a weak point and cause unpredicted fatigue crack. For determining the appropriate period of inspection, it is important to understand the crack growth behavior in longitudinal welded joint of the primary member. In this study, fatigue strength of longitudinal welded joints with the presence of blowholes is studied. To obtain the crack propagation life, crack propagation analysis for large-scaled girder containing blowhole in its welded joint between web and flange is performed. In the end, the analysis results associated with the traffic volume data is employed to predict how long will it takes from the moment crack initiates from blowholes until reach member failure.

Fatigue crack initiation assessment of load-carrying cruciform welded joints under low cycle actions Reviewed

Yuko Ohashi, Takeshi Hanji, Kazuo Tateishi, Masaru Shimizu

Proceedings of the ISSS 2019 2019.11

Authorship：Corresponding author Language：English

Local strain based low cycle fatigue assessment of gusset plates in steel truss bridges under earthquake Reviewed

Chao Jiang, Takeshi Hanji, Kazuo Tateishi, Masaru Shimizu

Proceedings of the ISSS 2019 2019.11

Authorship：Corresponding author Language：English

Steel truss bridges are widely used for intermediate spans because of its light weight and high load-carrying capacity. Failure accidents of truss bridge have shown that fracture of some members can lead to collapse of the whole bridge, called fracture critical member (FCM). In this study, from the viewpoint of low cycle fatigue, dynamic behavior of FCM under great earthquake was discussed. The results of finite element analysis indicated that large strains were locally occurred at the end of fillets of a gusset plate and around the boundary between the gusset and main chords, which have the possibility to become cracking sites due to low cycle fatigue.

Estimation of fatigue crack propagation behavior in steel plate subjected to out of plane bending Reviewed

Kentaro Horio, Kazuo Tateishi, Masaru Shimizu, Takeshi Hanji

Proceedings of the ISSS 2019 2019.11

　 PREV - NEXT 　

<HANJI Takeshi>

Papers - HANJI Takeshi