Abstract： A new low-cost seismic isolation system based on spring tube bracings has been proposed and studied at the Structural and Earthquake Engineering Laboratory of Istanbul Technical University. Multiple compres...Abstract： A new low-cost seismic isolation system based on spring tube bracings has been proposed and studied at the Structural and Earthquake Engineering Laboratory of Istanbul Technical University. Multiple compression-type springs are positioned in a special cylindrical tube to obtain a symmetrical response in tension and compression-type axial loading. An isolation floor, which consists of pin-ended steel columns and spring tube bracings, is constructed at the foundation level or any intermediate level of the building. An experimental campaign with three stages was completed to evaluate the capability of the system. First, the behavior of the spring tubes subjected to axial displacement reversals with varying frequencies was determined. In the second phase, the isolation floor was assessed in the quasi-static tests. Finally, a scaled 3D steel frame was tested on the shake table using actual acceleration records. The transmitted acceleration to the floor levels is greatly diminished because of the isolation story, which effects longer period and higher damping. There are no stability and self- centering problems in the isolation floor.展开更多
The spring-back of a bending metal tube was studied through extensive experiments and finite element method （FEM） analysis. An approximate equation for the spring-back angle of bending was deduced. It is noted that ...The spring-back of a bending metal tube was studied through extensive experiments and finite element method （FEM） analysis. An approximate equation for the spring-back angle of bending was deduced. It is noted that the mechanical properties of the material （in a tubular form） are quite different from those found in the standard tensile tests （when the materials are in bar forms）. This is one of the major reasons that result in the discrepancies in the outcomes of experimental study, FEM calculations, and spring-back analysis. It is therefore of crucial importance to study the mechanical properties of the materials in their tubular forms. The experiments and FEM simulations prove that the spring-back angle is significantly affected by the mechanical properties of the materials. The angle decreases accordingly with plastic modulus, but changes inversely with the hardening index and elastic modulus The spring-back angle is also affected by the conditions of tube deformation： it increases accordingly with the relative bending radius but changes inversely with the relative wall thickness. In addition, the spring-back angle increases nonlinearly with the bending angle.展开更多
In this paper we use the finite element analysis software ANSYS10.0 to establish a finite element model for pressure gauge C -spring tube, and the main factors affected the relation between the pressure and distortion...In this paper we use the finite element analysis software ANSYS10.0 to establish a finite element model for pressure gauge C -spring tube, and the main factors affected the relation between the pressure and distortion displacement are analyzed. The results show that with the increasing of the spring tube wall thickness T and the minor axis length B, the elastic rigidity of spring tube increases, which is reduced with spring tube diameter D. Moreover, the major axis length H increases. Meanwhile, a pressure gauge spring tube has been optimized according to the simulation results bused on a model with special features, and the design results achieve the intended purpose. The analysis results provide a reliable method for the research and design of similar elastic elements.展开更多
基金Research Project 36997 of Istanbul Technical University Research Funds
文摘Abstract： A new low-cost seismic isolation system based on spring tube bracings has been proposed and studied at the Structural and Earthquake Engineering Laboratory of Istanbul Technical University. Multiple compression-type springs are positioned in a special cylindrical tube to obtain a symmetrical response in tension and compression-type axial loading. An isolation floor, which consists of pin-ended steel columns and spring tube bracings, is constructed at the foundation level or any intermediate level of the building. An experimental campaign with three stages was completed to evaluate the capability of the system. First, the behavior of the spring tubes subjected to axial displacement reversals with varying frequencies was determined. In the second phase, the isolation floor was assessed in the quasi-static tests. Finally, a scaled 3D steel frame was tested on the shake table using actual acceleration records. The transmitted acceleration to the floor levels is greatly diminished because of the isolation story, which effects longer period and higher damping. There are no stability and self- centering problems in the isolation floor.
文摘The spring-back of a bending metal tube was studied through extensive experiments and finite element method （FEM） analysis. An approximate equation for the spring-back angle of bending was deduced. It is noted that the mechanical properties of the material （in a tubular form） are quite different from those found in the standard tensile tests （when the materials are in bar forms）. This is one of the major reasons that result in the discrepancies in the outcomes of experimental study, FEM calculations, and spring-back analysis. It is therefore of crucial importance to study the mechanical properties of the materials in their tubular forms. The experiments and FEM simulations prove that the spring-back angle is significantly affected by the mechanical properties of the materials. The angle decreases accordingly with plastic modulus, but changes inversely with the hardening index and elastic modulus The spring-back angle is also affected by the conditions of tube deformation： it increases accordingly with the relative bending radius but changes inversely with the relative wall thickness. In addition, the spring-back angle increases nonlinearly with the bending angle.
文摘In this paper we use the finite element analysis software ANSYS10.0 to establish a finite element model for pressure gauge C -spring tube, and the main factors affected the relation between the pressure and distortion displacement are analyzed. The results show that with the increasing of the spring tube wall thickness T and the minor axis length B, the elastic rigidity of spring tube increases, which is reduced with spring tube diameter D. Moreover, the major axis length H increases. Meanwhile, a pressure gauge spring tube has been optimized according to the simulation results bused on a model with special features, and the design results achieve the intended purpose. The analysis results provide a reliable method for the research and design of similar elastic elements.
