Static displacement expansion for cable-strut tensile structures by concurrently using mode compensation and optimization strategies

Abstract

For a specific load, the displacements of a real cable-strut tensile structure can be approximately expressed by only a few contribution modes. The displacements can thus be quickly expanded based on finite sensor locations by the traditional contribution-mode based method (TCMM). However, the TCMM has two shortcomings. First, mode truncation errors occur by neglecting non-contribution modes. Second, too many sensors are needed when a load case has too many contribution modes. In this paper, two strategies named mode compensation strategy (MCS) and mode optimization strategy (MOS) are suggested, respectively. The MCS aims to compensate mode truncation errors observed in the TCMM, with all non-contribution modes treated as one integral compensation mode. The MOS attempts to reduce the quantity of contribution modes by finding the best virtual mass distribution. An improved contribution-mode based method (ICMM) using both the MCS and the MOS is thus proposed. An annular tensile cable-truss canopy structure with a span of 200 m is numerically analyzed. For the load case with 26 loading points and 16 contribution modes, the MOS can significantly reduce the number of contribution modes to 4. Besides, the ICMM presents high expansion accuracy with far less sensor locations than the TCMM and the Guyan method.