Analysis And Calculation On The Torsion Elastoplastic Of Centrifugal Concrete Filled Thin-Walled Steel Tubular Members

According to the analysis and the calculation of Centrifugal Concrete Filled Thin-Walled Steel Tubular (CFTST) members under torsion load. In this paper, the load history of the member can be divided into three phases by the analysis of stress-strain curve, thus the failure characters and the corresponding bearing capacity guideline can be defined. This paper summarizes the analysis process and phenomena, describes the failure characters. By the way of mini-element's ultimate state balance, the calculating formula of the CFTST member under torsion load be present. The analysis shows that the theoretical calculating results are very near to the test results.Conclution: The torsion bearing capacity of the CFTST is higher than the total ones of the Thin-Walled Tube and the Concrete Tube, because the inner concrete tube not only has a higher strength due to the restrain of outer steel tube, but also ensure the steel tube geometric stability. So, the CFTST member has a fine quality to bear torsion load.To further illustrate the CFTST members, the elasto-plastic analysis and calculation are performed. In this paper the linear finite element analysis of the members is carried out using the general program ANSYS. The relationships between torsion load and member's end-part turn angle are calculated. Also, the non-linear analysis using ANSYS program is performed under some hypothesis in this paper.