Theoretical analysis and experimental study on sensitivity of element-length error in cable-strut tensile structures

Abstract

In a real cable-strut tensile structure, the element-length errors are inevitable. To understand their effects on the bearing capacity of a cable-strut tensile structure, the element-length error sensitivity analysis was investigated in this study. First, mathematical model of the element-length error was proposed based on stochastic theory. By combining the balance equation, geometric equation, and physical equation, the fundamental equation between the pre-stress deviation and element-length error was derived. After that, pre-stress deviation statistics characteristic was achieved with the help of statistical theory and the element-length error sensitivity analysis method was formulated. Then, a cable-strut tensile structure model with a diameter of 5.0 m was designed and fabricated to validate the proposed method. The element-length was set adjustable in order to simulate the element-length errors. Making use of the measured internal forces induced by element-length errors, the error sensitivity of each kind of element was achieved. In addition, a finite element model was also established with the commercial software ANSYS. The element-length errors were simulated by the changes of element-length due to temperature variations. The results of the three models coincided with each other satisfactorily, verifying the effectiveness of the proposed mathematical model. It was found that different elements had different error sensitivities. The error sensitivity of the hoop cables was most prominent, the ridge cables and diagonal cables the second, and the struts the third.