OHTORI Yasuki Research Institute, Central Research Institute Of Electric Power Industry, Abiko Research Laboratory, Geotechnical & Earthquake Engineering Department, Chief Researcher, 我孫子研究所・地盤耐震部, 主任研究員
FUJINO Yozo The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (20111560)
In this research, finite element model of laminated rubber bearings is developed and their design criteria are proposed.
At the first part of the research, the material tests of rubber are systematically conducted to understand their basic mechanical behaviors, I.e., stress-strain relation, rate dependency and failure state. Based on the results of these tests, a constitutive law, which consists of parallel combination of elasto-plastic body and hyper elastic body, is proposed. Furthermore, a failure criterion, which is the combination of polynomials of the strain invariants, is also developed. The proposed constitutive law and the failure criterion are shown to agree well with the experimental results. Then, an analysis method is proposed, in which the strain field of laminated rubber bearings measured by image processing is combined with the finite element analysis to confirm the applicability of the proposed model to the bearing including local deformation. Furthermore, the bulk modu
lus of rubber materials is computed by this image-based analysis method.
At the second part of the research, three dimensional finite element model of laminated rubber bearings is developed. Here, a mixed finite element method is employed to incorporate the proposed constitutive model and to stabilize the numerical computation at large deformation. In order to verify the accuracy of the developed model, multi-axial loading experiments and failure experiment of laminated rubber bearings are conducted. Applicability of the developed finite element model is verified in comparison with these experimental results and developed finite element model is shown to have the capability to predict the behavior of the rubber bearings.
At the last part of the research, design criteria for vertical, rotational, and torsional deformation, and failure of laminated rubber bearings are proposed. The proposed criteria show good agreement with experimental results and/or finite element prediction, which implies that the accuracy of the present design code can be improved considerably. Less