Observation and evaluation of plastic collapse for double-notch pipe

Suzuki, Ryosuke*; Matsubara, Masaaki*; Sakamoto, Kenji*; Suzuki, Masato*; Shiraishi, Taisuke*; Yanagihara, Seiji*; Izawa, Satoru*; Wakai, Takashi

Experimental Techniques, 40(1), p.253 - 260, 2016/09

https://doi.org/10.1007/s40799-016-0030-z

The plastic collapse behavior and strength were investigated for an austenitic stainless steel pipe with two 90 through-wall notches perpendicular to the pipe axis direction. Double-notch specimens with various notch separation distances were coated with photo-plastic film. Arbitrary combined axial tensile and bending loads were applied to the specimens. Changes in the photo-plastic fringe pattern were observed during the tests to investigate the plastic collapse behavior. The plastic collapse strength was evaluated using a model based on an elastic-perfectly plastic body. The photo-plastic fringe patterns at the experimental plastic collapse point differed based on the loading history. Thus, the plastic collapse behavior depends on the loading history. In addition, the plastic collapse strength differed based on the loading history and hardly depended on the notch separation distance. The experimental plastic collapse occurred before reaching the theoretical plastic point for only some pure-tension loading tests. Thus, the model analysis based on an elastic-perfectly plastic body used in this study might give an unconservative estimate for the plastic collapse of a stainless steel pipe subjected to a pure tension load.

Collapse strength of SUS304 steel pipes with circumferential multiple notches subjected to axial tension and bending

Shiraishi, Taisuke*; Matsubara, Masaaki*; Suzuki, Ryosuke*; Suzuki, Masato*; Yanagihara, Seiji*; Sakamoto, Kenji*; Wakai, Takashi

Nihon Kikai Gakkai M&M 2012 Zairyo Rikigaku Kanfarensu Koen Rombunshu (CD-ROM), 3 Pages, 2012/09

Plasticity collapse strength of stainless piping subjected to combined tension and bending

Matsubara, Masaaki*; Hayashi, Tatsuya*; Suzuki, Masato*; Shiraishi, Taisuke*; Sakamoto, Kenji*; Wakai, Takashi

Nihon Kikai Gakkai M&M 2011 Zairyo Rikigaku Kanfarensu Koen Rombunshu (CD-ROM), 2 Pages, 2011/07

In this study, we investigated the influence of two or more flaws on the collapse strength of austenitic stainless steel piping to improve the safety of a nuclear power plant. The multiple flaws may be more often than single flaw. Therefore, it is important to evaluate the collapse strength of the piping with multiple flaws. Piping with a single flaw and multiple flaws were used in the examination. Collapse strength of the piping is verified under the combination condition of tension and bending. It aims to model from multiple flaws to the single flaw for simplification of the. As a result, (1) It is possible to evaluate the collapse strength by identifying the multiple flaws as the single flaw conservatively. (2) On each load condition, the parallel notches on piping can be accounted to be the single notch.