KAWADA Industries Inc.

Tadotsu, Japan

KAWADA Industries Inc.

Tadotsu, Japan
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Higashiyama H.,Kinki University | Yoshida K.,KAWADA Industries Inc. | Inamoto K.,Nippon Stud Welding Co. | Matsui S.,Osaka Institute of Technology | Kaido H.,KAWADA Industries Inc.
Journal of Constructional Steel Research | Year: 2014

This paper presents an evaluation of the fatigue strength of headed studs welded with improved ferrules under rotating shear force. In steel-concrete composite structures, shear connectors are essential components to transfer shear forces at the interface between steel and concrete. Particularly, headed studs in steel-concrete composite decks for highway bridges are subjected to rotating shear force when vehicle loads pass through the steel-concrete composite decks. The authors have developed welding ferrules for headed studs with higher fatigue duration than conventional headed studs. In this study, the rotating shear force was applied to the improved headed studs by using a specially developed testing machine in order to determine the fatigue strength in association with the concrete strength. The fatigue strength of the headed studs increased with the higher concrete strength and two failure modes were observed. Finally, the average S-N curves in correspondence with concrete strengths were determined for the improved headed studs. © 2013 Elsevier Ltd.


Yoshida K.,KAWADA Industries Inc. | Higashiyama H.,Kinki University | Inamoto K.,Nippon Stud Welding Co. | Matsui S.,Osaka Institute of Technology | Kaido H.,KAWADA Industries Inc.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2013

The purpose of this study is to evaluate the fatigue strength of headed studs using an improved welding ferrule under rotating shear force. In the fatigue tests, to prevent up-lift of the specimen, vertical force was introduced in proportion to the rotating shear force. From the fatigue test results, two kinds of failure modes were observed. One of those is a failure of the headed stud accompanying with concrete crushing around its weld collar. Another is a failure of the bottom steel plate due to initiation of a fatigue crack from the weld toe. The fatigue life of the headed studs tested in this study showed some scatter in the same manner as the fatigue life of concrete. Hence, the treatment of probability is needed to evaluate the S-N curve for the conventional and durable headed studs. In this study, the test results indicated that probability distributions of the fatigue life conform to logarithmic normal distribution and 3-parameter Weibull distribution. Finally, the logarithmic normal distribution was applied to determine the average fatigue life of the conventional and durable headed studs tested and the S-N curves for both headed studs were obtained. Then, the average fatigue life of the durable headed studs increased in three times when compared to that of the conventional headed studs.


Omura M.,Fujiko Co. | Iwai D.,Fujiko Co. | Kato M.,Chodai Co. | Morino M.,Chodai Co. | Hatakenaka S.,KAWADA Industries Inc.
IABSE Conference, Nara 2015: Elegance in Structures - Report | Year: 2015

A project for construction of the Japan's longest pedestrian bridge is underway with private funds, in Mishima city, Shizuoka prefecture. At the moment, the basic configuration, basic planning, aesthetic study and wind tunnel test of the suspension bridge has been completed. The basic bridge configuration, the structural configuration and the aesthetic study of the above-mentioned pedestrian suspension bridge with 400m long center span are reported in this study.


Kotani Y.,KAWADA Industries Inc. | Okano S.,Osaka University | Tsuyama T.,KAWADA Industries Inc. | Mochizuki M.,Osaka University
Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society | Year: 2016

In manufacturing of the steel bridge, fillet welded T-joint is widely used and angular distortion is often generated. So, reduction or control of angular distortion without additional processes to welding is strongly demanded because it takes great time and effort to correct the angular distortion. In this study, the effectiveness of welding with trailing reverse-side flame line heating for preventing angular distortion was investigated through the welding experiment and numerical simulation in submerged arc welding of fillet T-joint with three different thick flange plate. First, the heat source models for numerical analysis of both submerged arc welding and flame line heating were constructed based on the comparison with the measured temperature histories and angular distortion. And then, these heat source models were used in combination with various kinds of distance between two heat sources to make clear the appropriate distance condition for smallest angular distortion was 150 mm, and it doesn't depend on thickness of flange plate. It was also confirmed that the experimental angular distortions were in good agreement with those calculated. With a focus on the influence of thickness of flange plate, the reduction of angular distortion by welding with trailing reverseside flame line heating becomes smaller with increasing thickness of flange plate. However, angular distortion could be adequately prevented under the appropriate flame line heating condition in either thickness of flange plate because the welding-induced angular distortion also becomes smaller with increasing thickness of flange plate. Thus, it was concluded that welding with trailing reverse-side flame line heating could be useful for preventing angular distortion of fillet T-joint, which is a component of steel bridge, enough not to correct it after welding.


Kaneko K.,Japan National Institute of Advanced Industrial Science and Technology | Kanehiro F.,Japan National Institute of Advanced Industrial Science and Technology | Morisawa M.,Japan National Institute of Advanced Industrial Science and Technology | Akachi K.,KAWADA Industries Inc. | And 3 more authors.
IEEE International Conference on Intelligent Robots and Systems | Year: 2011

This paper presents the development of humanoid robotics platform - 4 (or HRP-4 for short). The high-density implementation used for HRP-4C, the cybernetic human developed by AIST, is also applied to HRP-4. HRP-4 has a total of 34 degrees of freedom, including 7 degrees of freedom for each arm to facilitate object handling and has a slim, lightweight body with a height of 151 [cm] and weight 39 [kg]. The software platform OpenRTM-aist and a Linux kernel with the RT-Preempt patch are used in the HRP-4 software system. Design concepts and mechanisms are presented with its basic specification in this paper. © 2011 IEEE.


Tsuyama T.,KAWADA Industries Inc. | Yuda M.,KAWADA Industries Inc. | Nakai K.,Ehime University
Welding in the World | Year: 2014

In the fabrication of steel structures, the method of gas-shielded arc welding is widely utilized with pure CO2 gas. However, the welding with pure CO2 gas is limited with respect to the heat input in order to maintain the fixed mechanical properties of weld metal. A new welding method for increasing weld deposit in every weld bead under keeping the fixed mechanical properties of the weld metal is proposed. An electrically heated filler wire, hereafter referred to as hot wire, was inserted to the weld pool neighboring the arc formed with a leading welding electrode. By using a hot wire without arc, the increase in heat input could be suppressed, but the amount of weld deposit could be greatly increased. In the present investigation, the effects of the welding conditions on both the microstructure and mechanical property of the weld metal are clarified and discussed from the view point of the improvement of welding conditions. Mechanical properties of the weld metal formed with F-metal active gas (MAG) could be greatly improved under high heat input. The microstructure formed with F-MAG is so fine because of the change in the chemical composition of the weld metal by the use of the hot wire. The refined microstructure in F-MAG might improve the mechanical properties of the weld metal. © 2013 International Institute of Welding.


Tsuyama T.,KAWADA Industries Inc. | Nakai K.,Ehime University | Tsuji T.,KAWADA Industries Inc.
Welding in the World | Year: 2014

In the fabrication of steel bridge, submerged arc welding (SAW) is widely utilized. In order to increase the efficiency for the production of welds, the increase in electrode such as SAW with multiple wire electrodes is effective. However, heat input also increases with increasing the number of electrode. The new welding method based on SAW method with one electrode, F-SAW, was developed in the present investigation. An electrically heated filler wire, hereafter referred to as hot wire, was inserted into the rear part of weld pool made with leading SAW electrode. By using the hot wire without arc, increase in heat input could be suppressed but the amount of weld deposit could be greatly increased. Welding speed of F-SAW for deck plate 16-mm thick became two times compared with that with ordinary SAW. In the present study, mechanical properties of the weld metal formed with F-SAW were clarified. Mechanical properties of the weld metal formed with F-SAW could be improved, compared with those with SAW. Moreover, those with F-SAW was greatly improved by selecting the hot wire and cut wire. The microstructure formed with F-SAW was so fine. The refined microstructure in F-SAW might improve the mechanical properties of the weld metal. © 2014 International Institute of Welding.


Tsuyama T.,KAWADA Industries Inc. | Nakai K.,KAWADA Industries Inc. | Akiyama M.,KAWADA Industries Inc. | Takahashi B.,KAWADA Industries Inc. | And 2 more authors.
Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan | Year: 2013

New welding method (F-MAG) based on CO2 gas-shielded arc welding method (MAG) was developed to increase deposition rate of weld metal. In F-MAG, filler wire (hot-wire) heated using direct-current was put into rear part of weld-pool formed with main electrode used in MAG. Multi-layered weld metals were prepared using both F-MAG and MAG. Microstructures of both as-weld and reheated zones in uppermost layer of the multi-layered weld metals were examined and the effects of microstructures on mechanical properties were analyzed. Both the asweld and reheated zones of weld metal formed with F-MAG consisted of acicular ferrite (AF) and/or equiaxed ferrite and so on. Both strength and elongation in as-weld and reheated zones formed with F-MAG were superior compared with those formed with MAG. It could be suggested that strength increased by refinement of AF due to increase in the concentration of alloy elements being contained in hot-wire. Larger elongation of weld metal in F-MAG compared with that in MAG could be analyzed in terms of the aggregate of AFs with almost parallel slip systems between neighboring AFs, hereafter referred as to ALPS. The number of AFs contained in an ALPS formed in weld metal formed with F-MAG is larger than that with MAG, in spite of the sizes of ALPSs in weld metals formed with MAG and F-MAG being almost same between them. Deformation occurs over a lot of AFs in the case of finer AF through the rotation of tensile test piece during deformation.


Kotani Y.,KAWADA Industries Inc. | Okano S.,Osaka University | Kobayashi S.,Osaka University | Tsuyama T.,KAWADA Industries Inc. | Mochizuki M.,Osaka University
Welding International | Year: 2016

Reduction or control of angular distortion without additional processes is demanded because it takes a lot of time and effort to correct the angular distortion of fillet-welded T-joints. In this study, the reduction or control of angular distortion of both sides of a fillet-welded T-joint by welding with trailing reverse-side gas heating was investigated through a welding experiment and its numerical simulation. First, the effect of gas heating position and intensity on the reduction in angular distortion was experimentally investigated using a gas burner. The results showed that angular distortion became smallest when reverse-side heating using the gas burner was located 50 mm backward of the welding torch. Also, the concentrated gas flame with increased propane and oxygen gas flow was effective for reducing angular distortion. It was clarified that the angular distortion could be controlled completely with an appropriate reverse-side gas heating condition. Next, the numerical simulation model of welding and gas heating was constructed based on comparison with the measured temperature histories and angular distortion. Through the numerical simulation of welding with a trailing reverse-side gas, more detailed understanding of the effect of gas heating condition on reduction in angular distortion was developed. In addition, it was confirmed that the gas heating position for the smallest angular distortion is dependent on the temperature distribution along the thickness of the flange plate. © 2016 Informa UK Limited, trading as Taylor & Francis Group.


Trademark
KAWADA Industries Inc. | Date: 2015-10-27

Robots for fiber processing; robots for glass processing; robots for coating; robots for plastic processing; robots for electronic circuit assembling; robots for electronic component manufacturing; robots for rubber component processing.

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