Erection Simulation Of Cable-Strut Tensile Structures And Motion Tracing Of Planar Pin-bar Mechanisms

The erection simulation analysis of cable-strut tensile structures(CSTS) and the deployable integral lifting construction analysis of cylindrical latticed shells are the main research topics in this thesis. The shape-finding analysis of slack cable-bar assemblies is involved in the former topic, and the motion tracing analysis of planar pin-bar mechanisms can describe the latter topic well. Both of the topics are of great significance for engineering application and theoretical reasearch.Firstly, based on the catenary cable element model, a new compatible equation which reflects the relationship between the unelongated cable length and its tensile foce, is put forward. Using the compatible equation, the conversion between the cable's unelongated length and its tensile force can be achieved rapidly and steadily in simple bichotomy method, even without iteration. The chord-direction stiffness expression of catenary cable is also deduced on request of shape-finding in dynamic relaxation method. The expression can describe both large-slack cable and prestressed cable element.The dynamic damping dynamic relaxation method is introduced copiously, in which slack cable's chord-direction stiffness and bar's linear stiffness assemble the node's virtual mass needed in iteration process. Value of X named the stiffness amplification factor which affects the rapidity of convergence is discussed. It is found that the best λ's value is hard to be given. According to the author's experience, when X is assigned the value between 0.5~2.0, it is rapid enough to gain convergence for the flexible structure's shape-finding.Based on summing up the characteristics and mathematical description of shape-finding problems, this thesis simulates the erection processes of a Geiger cable dome and a sunflower-patterned spatial cable-truss tensile structure. The good results illustrate that it's an effective way to calculate such problems in dynamic relaxation method with catenary cable element. Otherwise, the unelongated length of prestressed calbe is solved for the first time in catenary cable description but not in bar's.This thesis also makes asymmetric lifting construction analysis of several planar pin-bar mechamnisms in dynamic relaxation method, and summarizes motion characteristics of the system during the lifting construction, with the influence of number of slings and position of nodes discussed. The results reflect that the motion status of planar pin-bar mechanisms cann't be decided only by system's geometry as deployable structures, but is determined by system's geometry, placed load and motion drive.At the end of the thesis, some conclusions are summarized and the problems that should be studied further are put forward.