Papers by Keyword: Joint Strength

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Authors: Fu Long Liu, Xiao Cong He, Lun Zhao
Abstract: Clinching is a high-speed mechanical fastening technique for point joining of sheet material. In order to investigate the influence of material property on the mechanical property and failure mode of clinched joints, three types of clinched joints in aluminum alloy sheet were tested under tension-shear loading with MTS landmark, separately. Results showed that the property of the substrate had effective on the performance of clinched joints. Clinched joints had higher strength and good energy absorption capacity when the strength of the substrate was higher. The strength and energy absorption capacity of the clinched joints were evaluated via load-displacement curves. While the failure modes of clinched joints were all the same: neck facture failure.
Authors: Fu Long Liu, Xiao Cong He, Yu Qi Wang
Abstract: This paper studied the performance of self-piercing riveting (SPR) and adhesive hybrid joints of different adhesive, including strength, capacity of energy absorption, failure mode and failure mechanism of the hybrid joints. The performances of SPR-adhesive hybrid joints were compared with SPR joints. SPR-adhesive hybrid joints and SPR joints were tested under a tension loading. The test results showed that adhesive have a function of improving the strength of SPR joints; however, the capacity of energy absorption of SPR joints was weakened. While the adhesive have no effect on the failure modes of SPR joints. When appropriate adhesive was selected, the overall performance of SPR-adhesive hybrid joints was superior to SPR joints. In a word, the combination of SPR and adhesive could get a well jointing structure.
Authors: Kazuki Fujita, Keizo Nishikori, Takeshi Iwamoto
Abstract: In various kinds of shape memory alloy (SMA), Fe-based SMA (Fe-SMA) shows smaller shape memory effect compared with the other SMAs. However, Fe-SMA shows huge advantages on the excellent formability, machinability, etc. Moreover, its production cost is cheaper than other SMAs; therefore, the alloy is attempted to be applied to structural members such as joints and dampers. Since bending deformation at higher deformation rate is generated in the members, especially the joints, due to impact force such as earthquake or wind, a clarification on the bending strength of the joints at various deformation rate is strongly required. In this study, at first, it is attempted that the bending strength and its rate sensitivity of the joints which consist of Fe-based SMA are experimentally estimated by the three-point bending test at various deformation rate. Then, the force balance equation is challenged to be derived to predict the bending strength.
Authors: Yu Lin He, Liu Jun Huang
Abstract: Due to its advantages over the spot welding technique, clinch joining technique is applied extensively in the automobile, electrical apparatus, etc. The quality and strength of the joints are the hot issues of the technique, which are severely affected by the processing parameters and die structure parameters. Clinch joining experiments of aluminous sheets L5 were carried out under various blank holder forces and die structure parameters, and the influence of the parameters on the failure mode, section quality and strength of the joints were analyzed. The results show that the failure of the joints is mainly the shearing and a good section quality and high shearing strength of the joints can be obtained by reasonable processing parameters and die structure parameters.
Authors: Yasunori Harada, Makoto Fukunaga, Kenzo Fukaura, Satoru Ujihashi, Yuji Kobayashi
Abstract: The butt joining of dissimilar sheets using a shot peening process was investigated. Shot peening is a surface treatment and improves the performance of engineering components. In shot peening, the substrate undergoes a large plastic deformation near its surface due to a hit with many shots. Thus, plastic flow characterized by a shear droop occurs at the edge of the substrate due to shot peening. When the dissimilar sheets with the edge of the notch geometry are connected without level difference and shot-peened the connection, the sheets can be joined due to the plastic flow generated by the large plastic deformation during shot peening. In the experiment, a compressed-air-type shot peening machine was employed. The influences of processing conditions on the joining of the dissimilar sheets were examined. The joint strength increased with the kinetic energy of shots. It was found that the present method using shot peening process was effective in joining dissimilar sheets.
Authors: K. Shinozaki, K. Koyama
Abstract: Brazing of Al to Cu using Al-Si-Mg-Bi brazing alloy has been carried out in a vacuum furnace. In the brazed interlayer, there were two kinds of intermetallic compounds. One of these intermetallic compounds was θ phase and the other was δ(Cu3Al2). Tensile strength of the joint was only about 15MPa. Deformation behavior of Al/Cu brazing joint was brittle without deformation of the base metal. The specimen was fractured in the intermetallic compound which was mainly θ phase. In order to improve the tensile strength of Al/Cu dissimilar joint, Cu cladding Ag (thickness: 0.1mm) substituted for Cu. As the result, tensile strength of the joint was about 70MPa and the specimen was fractured in an Al base metal. In this joint, plate-like intermetallic compound, δ (Ag2Al) was formed in the brazed interlayer. The shape of δ(Ag2Al) was quite different from θ phase found in Al/Cu joint. It was considered that the shape of reaction layer remarkably affected to the strength of the Al/Ag-Cu clad dissimilar joint.
Authors: Ikuo Shohji, Susumu Arai, Naoki Kano, Noboru Otomo, Masahisa Uenishi
Abstract: A Cu brazing sheet has been developed using a Cu-P composite plating method. A Cu-P composite plating layer, which contains 7mass%P, was formed on a Cu plate with a copper sulfate solution including P particles. The melting start temperature of the Cu-P composite layer was determined to be approximately 765°C. Microstructure and joint strength of a brazed joint with the Cu-P composite layer were investigated and compared with those of the joint with a conventional Cu-7P filler foil. As the results of the study, it was clarified that the Cu-P composite layer developed is feasible to use as a brazing material for Cu and Cu alloys.
Authors: Kazuyoshi Saida, Woo Hyun Song, Kazutoshi Nishimoto, Makoto Shirai
Abstract: The diode laser brazing of heat-resistant alloys with precious filler metals has been conducted using tandem beam which consisted of preheating beam and main brazing beam. The 1mm thick Inconel 600 and A286 alloys were laser-brazed with the 0.5mm diameter Au-18%Ni, Ag-10%Pd and Ag-21%Cu-25%Pd filler metals using a brazing flux. The processing parameters of laser power of tandem beam and brazing clearance were varied. Sound butt joints could be obtained by using tandem beam with laser powers of 200-400W/100-150W even at the narrow gap brazing below 0.3mm where the melted filler metal did not infiltrate completely the joint gap by only using the main brazing beam (single beam). The tensile strength of the brazed joint using Ag-Pd filler metal increased with decreasing brazing clearance and attained about 70% of the base metal strength at brazing clearance of 0.1mm, while those using Au-Ni and Ag-Cu-Pd filler metals were comparable to the base metal strength at any brazing clearance between 0.1-1.5mm. The preheating during the tandem beam brazing resulted in superior brazability at the narrow gap to wide gap brazing because of the improvement in wetting/spreading and erosion esistance of melted filler metal by depressing the extremely high peak temperature and steep temperature distribution in the base metal.
Authors: Xiao Long Zhou, Fan Xiao
Abstract: In order to analyze reliability for strength of pre-stressed pipe pile welded joints in common construction activities, perform checking calculation to welded joint strength in various construction activities with the weld check formula in consideration of the influence coefficient of the eccentrically loaded end plate, compare with the shear strength of the pipe pile end plate porthole and the tensile strength of the steel bar pier head, and analyze from overall safety of pipe pile application before obtain the conclusion: the strength of the weld joint made according to relative codes is far more than the strength of the weak part of the pipe pile, but some severe weld defects will make weld joint become the first part to be damaged. One recommendation is increase the joint strength between the anchorage hole of the pipe pile end plate and the pre-stressed steel bar pier head; the other is to make the new welding construction specifications for pipe pile joint, improve requirements to joint welding construction, reduce welding duration, reduce working strength and improve welding quality stability.
Authors: Ikuo Shohji, Ryohei Arai, Hisao Ishikawa, Masao Kojima
Abstract: The tensile properties of Sn-x(x=1, 2, 3)Ag-0.5Cu-0.05Ni-0.005Ge (mass%) alloys were investigated. In addition, the ball shear force was investigated with solder balls and two types electrodes, Cu and electroless Ni/Au plated Cu, to examine joint reliability under heat exposure conditions. Tensile strength of the alloy decreases with decreasing the Ag content. On the contrary, elongation increases with decreasing the Ag content. When the Ag content reduces, primary β-Sn phases are coarsened and eutectic microstructures diminish. The decrease of the eutectic microstructures causes a reduction of the tensile strength. In as-soldered joints with Sn-Ag-Cu-Ni-Ge solder balls and Cu electrodes, the ball shear force increases with increasing the Ag content. However, the ball shear force decreases with increasing heat exposure time. After heat exposure treatment at 423 K for 500 h, the ball shear force is relatively stable at lower values regardless of the Ag content. In the joints with electroless Ni/Au plated Cu electrodes, the ball shear force slightly increases with increasing heat exposure time. Even after heat exposure treatment at 423 K for 500 h, hierarchy of the ball shear force is maintained. The ball shear force becomes high with increasing the Ag content.
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