ANALYSIS OF RUBBER BEARING BEHAVIOR WITH MATERIAL DETERIORATION
Makoto Obata 1* and Yoshiaki Goto 2
1 Department of Civil Engineering, Nagoya Institute of Technology, Gokiso-cho, Nagoya, Japan
2 Next Generation Seismic Engineering Laboratory, Nagoya Institute of Technology, Gokiso-cho, Nagoya, Japan
As rubber bearings play an important role in seismic design of bridges, it is of great necessity to accurately evaluate their deformation characteristics and fracture properties. Since ordinary rubber in rubber bearings is expected to undergo huge shear deformation as large as several hundred percent until failure and because they have material properties unique to rubber-like materials such as hyper elasticity, plasticity and viscosity, inevitably, large deformation problems and complicated stress-strain relationships must be considered for numerical analyses. Therefore, many researches have been aiming for accurate numerical simulation of the behavior of rubber bearings. In this work, the Mullins effect are focused among them. As for the Mullins effect, the formulation introduced so far, such as the one by Ogden-Roxburgh, does not necessarily reproduce the actual behavior very well under cyclic loading. This research attempts a deformation-based approach. Numerical simulation shows that a newly introduced damage surface can remedy the shortcomings the simple Mullins model.
Rubber bearings; Constitutive model; Numerical simulation