Yusuke Tomizawa
Hokkaido University
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Publication
Featured researches published by Yusuke Tomizawa.
Key Engineering Materials | 2016
Yusuke Tomizawa; Takehito Suzuki; Katsuhiko Sasaki; Ken-ichi Ohguchi; Daisuke Echizenya
Recently, Halt (Highly accelerated limit test) is widely employed for evaluation of reliability of electronic products. Halt condition is quite severe. The tested products are subjected to mechanical impacts, thermal shock, and vibration at same time. However, there has not been a reasonable and accurate evaluation method for Halt yet. To construct an accurate evaluation method of Halt, basic deformation mechanism of parts of the electronic products should be clarified from both experimental and theoretical points of view. In this paper, focusing on solder joints of circuit boards of electronic products, ratchetting deformation, especially, biaxial ratchetting deformation of solder joints is revealed from both experimentally and theoretically. The authors have already conducted biaxial ratchetting test combining axial and torsional cyclic loading using a tubular specimen of Type 304 stainless steel. However, as for solders, it is difficult to make tubular specimen. Since size of the solder joints is micron, a small size joint specimen of copper tube and solder is employed in this paper. First, to confirm the quality of the joint specimen such as boundary between copper and solder, both the tensile and cyclic loading tests are conducted at several temperatures using Sn-3Ag-0.5Cu. The basic characteristic of tensile and fatigue failure is obtained from these tests. After the confirmation of the accuracy of the joint specimen, biaxial ratchetting tests are conducted superposing the tensile load on cyclic torsion. The biaxial ratchetting tests are conducted using a biaxial loading testing machine developed for the joint specimens of solder and copper.
Applied Thermal Engineering | 2016
Yusuke Tomizawa; Katsuhiko Sasaki; Akiyoshi Kuroda; Ryo Takeda; Yoshihiko Kaito
Composite Structures | 2017
Kazuaki Katagiri; Katsuhiko Sasaki; Shinya Honda; Hikaru Nakashima; Yusuke Tomizawa; Shimpei Yamaguchi; Tomoatsu Ozaki; Hirosuke Sonomura; Atsushi Kakitsuji
Composite Structures | 2019
Kazuaki Katagiri; Shinya Honda; Sayaka Minami; Yusuke Tomizawa; Daiki Kimu; Shimpei Yamaguchi; Takuya Ehiro; Tomoatsu Ozaki; Hirosuke Sonomura; Sonomi Kawakita; Mamoru Takemura; Yayoi Yoshioka; Katsuhiko Sasaki
The Proceedings of the Materials and Mechanics Conference | 2017
Toshiki Kitao; Yusuke Tomizawa; Katsuhiko Sasaki; Ken-ichi Ohguchi; Daisuke Echizenya
The Proceedings of the Materials and Mechanics Conference | 2017
Kazuaki Katagiri; Katsuhiko Sasaki; Shinya Honda; Yusuke Tomizawa; Sayaka Minami; Shimpei Yamaguchi; Takuya Ehiro; Tomoatsu Ozaki; Hirosuke Sonomura; Yayoi Yoshioka; Atsushi Kakitsuji
The Proceedings of Mechanical Engineering Congress, Japan | 2017
Masataka Iwawaki; Ken-ichi Ohguchi; Katsuhiko Sasaki; Yusuke Tomizawa; Daisuke Echizenya; Nobuaki Ando
The Proceedings of Conference of Hokkaido Branch | 2017
Yusuke Tomizawa; Toshiki Kitao; Katsuhiko Sasaki; Ken-ichi Ohguchi; Daisuke Echizenya
The Proceedings of the Materials and Mechanics Conference | 2016
Yusuke Tomizawa; Katsuhiko Sasaki; Akiyoshi Kuroda; Ryo Takeda
The Proceedings of Mechanical Engineering Congress, Japan | 2016
Yusuke Tomizawa; Katsuhiko Sasaki; Akiyoshi Kuroda; Ryo Takeda