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Zhou, Z.; Nishida, Akemi; Kuwamura, Hitoshi*
Progress in Nuclear Science and Technology (Internet), 2, p.481 - 485, 2011/10
It is often necessary to study the collapse behavior of steel connections. In this study, the limit load of the steel pyramid-to-tube socket connection subjected to uniform compression was investigated by means of FEM and experiment. Three kinds of analysis were conducted: linear buckling, nonlinear buckling and modified Riks method analysis. The results of FEM analyses were compared with the experimental results. It shows that nonlinear buckling and modified Riks method analyses are more accurate than linear buckling analysis because they employ nonlinear, large-deflection analysis to estimate buckling loads. Moreover, the calculated limit loads from nonlinear buckling and modified Riks method analysis are close. It can be concluded that modified Riks method analysis is most effective for collapse analysis of steel connection under compression. At last, modified Riks method analysis is used to do the parametric studies of the thickness of the pyramid.
Zhou, Z.; Kuwamura, Hitoshi*; Nishida, Akemi
Procedia Engineering, 10, p.1433 - 1439, 2011/00
Times Cited Count：2 Percentile：72.8(Engineering, Multidisciplinary)Brittle fracture of structural steel for building use, in general, is triggered by a ductile crack initiated at notched surface after undergoing a noticeable amount of plastic strain. The initiation of the ductile crack correlates to the stress triaxiality-plastic strain states in the notched section. As stress triaxiality and plastic strain are usually derived from finite element analysis, two material models with voids (Gurson-Tvergaard-Needleman model) and without voids (Mises model) are used to do the analyses to study the stress triaxiality-plastic strain states in notched steels. The results show that the effect of micro voids on stress triaxiality-plastic strain states of notched steels is small until stability limit and become significant gradually after stability limit.
Zhou, Z.; Ito, Takumi*; Kuwamura, Hitoshi*
Proceedings of 9th Pacific Structural Steel Conference (PSSC 2010), Vol.2, p.1037 - 1042, 2010/10
The brittle fracture in steel buildings occurred at the events of the 1994 Northridge earthquake and the 1995 Hyogoken-Nanbu earthquake can actually take place only after several or dozens of cyclic loadings. To understand the correlation between ductile crack propagation and plastic deformation amplitude is important for finding a design method to prevent brittle fracture, which is not well studied, especially under cyclic loadings of large plastic deformation amplitude. An experimental study of ductile crack propagation in steel members is described in this paper. The correlations between maximum/(averaged) ductile crack depth and ductility amplitude/(normalized plastic deformation energy amplitude) were analyzed. It is found that using normalized plastic deformation energy amplitude is more accurate than using ductility amplitude in predicting ductile crack depth, and that the crack growth rate at cooling temperature is quicker than that at room temperature.
Zhou, Z.; Nishida, Akemi; Kuwamura, Hitoshi*
Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 5 Pages, 2010/10
It is often necessary to study the collapse behavior of steel connections. In this study, the limit load of the steel pyramid-to-tube socket connection subjected to uniform compression was investigated by means of FEM and experiment. The steel connection was modeled using 4-node shell element. Three kinds of analysis were done:linear buckling analysis, nonlinear buckling analysis and Riks method analysis. For linear buckling analysis uniform pressure was loaded directly. For nonlinear buckling analysis uniform pressure was loaded gradually and nonlinear material properties and large displacement were considered. For Riks method analysis uniform pressure was loaded by using the modified Riks method, and nonlinear material properties and large displacement were considered. The results of FEM analysis were compared with the experimental results. It can be concluded that arc length analysis is most suitable for collapse analysis of steel connection under compression.
