scholarly journals FEM ANALYSIS OF HIGH DAMPING LAMINATED RUBBER BEARINGS USING AN ELASTIC-PLASTIC CONSTITUTIVE LAW OF THE DEFORMATION HISTORY INTEGRAL TYPE

2010 ◽  
Vol 75 (658) ◽  
pp. 2171-2178 ◽  
Author(s):  
Takahiro MORI ◽  
Hideaki KATO ◽  
Nobuo MUROTA
Keyword(s):  
Fem Analysis ◽  
Constitutive Law ◽  
Integral Type ◽  
Deformation History ◽  
Elastic Plastic ◽  
Rubber Bearings

Buckling Load Estimation of Two-way Grid Domes Stiffened by Diagonal Braces Under Vertical Load

2021 ◽  
Vol 62 (1) ◽  
pp. 7-23
Author(s):  
Shiro Kato ◽  
Shoji Nakazawa ◽  
Yoichi Mukaiyama ◽  
Takayuki Iwamoto
Keyword(s):  
Slenderness Ratio ◽  
Fem Analysis ◽  
Buckling Load ◽  
Vertical Load ◽  
Imperfection Sensitivity ◽  
Plastic Buckling ◽  
Elastic Plastic ◽  
Alternative Formula ◽  
Efficient Scheme ◽  
Estimation Scheme

The present study proposes an efficient scheme to estimate elastic-plastic buckling load of a shallow grid dome stiffened by diagonal braces. The dome is circular in plan. It is assumed to be subject to a uniform vertical load and to be supported by a substructure composed of columns and anti-earthquake braces. Based on FEM parametric studies considering various configurations and degrees of local imperfections, a set of formulations are presented to estimate the elastic-plastic buckling load. In the scheme, the linear buckling load, elastic buckling load, and imperfection sensitivity are first presented in terms of related parameters, and the elasticplastic buckling load is then estimated by a semi-empirical formula in terms of generalized slenderness ratio using a corresponding plastic load. For the plastic load, the present scheme adopts a procedure that it is calculated by a linear elastic FEM analysis, while an alternative formula for the plastic load is also proposed based on a shell membrane theory. The validity of the estimation scheme is finally confirmed through comparison with the results based on FEM nonlinear analysis. The formulations are so efficient and simple that the estimation may be conducted for preliminary design purposes almost with a calculator. .

Elastic-Plastic FEM Analysis of Deformations of a Cylinder Subjected to Severe Uniaxial and Bilateral Compression by Flat Plates

1991 ◽  
Author(s):  
M. Gotoh ◽  
Y. Shibata
Keyword(s):  
Compressive Force ◽  
Fem Analysis ◽  
Plane Stress State ◽  
Deformation Pattern ◽  
Lateral Compression ◽  
The Finite Element Method ◽  
Ring Plane ◽  
Flat Plates ◽  
Elastic Plastic ◽  
Plastic Forming

Abstract Uni-lateral and bi-lateral elastic-plastic compressions of a circular cylinder with three different wall thicknesses by flat plates are numerically analysed by the Finite Element Method (FEM). J2-flow theory (J2F), and J2-Gotoh’s corner theory (J2G) which was previously proposed by one of the authors are used as the constitutive equations. In the case of uni-lateral compression, the cylinder is compressed up to a completely flattened shape, which is considered a kind of plastic forming processes. The deformed shapes and the compressive force are predicted better by J2G than by J2F. The spring-back behaviours are also analysed by imposing unloading process during deformation. The deformation process in the compression of a ring (plane stress state) and a spherical shell (axi-symmetric state) is also analysed. In the case of bi-lateral compression, the process is considered a kind of square-tube forming. In its final stage, the cylinder deforms into a completely unexpected shape which could be thought of as a square tube reinforced with ribs. The J2G allows the process to proceed at a lower compressive force than that for J2F. The effect of n-value (the strain-hardedning exponent) on the deformation pattern is also discussed.

Study on Restoring Force Models of Nonlinear Uplift Behavior of Unanchored Oil Storage Tank Under Strong Seismic Excitation

2004 ◽  
Author(s):  
Hai Yuan ◽  
Kazuma Kawano ◽  
Shoichi Yoshida
Keyword(s):  
Fem Analysis ◽  
Seismic Excitation ◽  
Force Model ◽  
Restoring Force ◽  
Plastic Model ◽  
Elastic Plastic ◽  
Loop Area ◽  
Perfectly Plastic ◽  
Oil Storage ◽  
S Curve

It had been reported that some unanchored oil storage tanks had serious damages due to its uplift behavior during strong seismic excitation. In some past studies, the uplift behavior of tank was generally simulated using elastic-plastic hysteresis models. But recently, a static FEM analysis for the cyclic uplift behavior of the shell-to-bottom joint of tank has shown that the hysteresis loop of the uplift force and uplift displacement is similar to S-curve with a narrow loop area. In order to investigate the effects of S-curve Restoring Force Model (SRFM) on the nonlinear response when it is used to simulate the tank’s uplift action, in this paper, the seismic response analyses of tank are carried out by using three kinds of restoring force models including SRFM, the Elastic-Perfectly Plastic Model (EPPM) and the Bilinear Elastic-Plastic Model (BEPM), and their results are compared with each other to examine the differences. In the analyses, the tank is modeled with an equivalent mass-spring model, and three recorded earthquake accelerations scaled to 0.6G are taken as the representation of strong motions. Consequently, this paper shows that SRFM gives the maximum response displacement and ductility respectively among the three restoring force models.

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