Research On Inversion Method Of Testing Grid Structure Axial Force By Natural Frequency

AbstractWith the development of economic, steel, especially the large-span truss structure, become more and more in china. However, due to China’s level of design and construction capabilities far behind the developed countries, accidents of truss structure occur frequently. The method of attach strain gauges to lever to real-time monitoring the internal forces are neither convenient nor economical,so we need to find another more simple and economical method. Due to the frequency method has many significant advantages,it is widely used in research in this area. Most researchers assumed truss structural member force as only withstand axial forces, node as hinged. Actually, truss structural rods not only afford axial force, but also bear a certain moment and shear force, at the same time, node is between the semi-rigid and elastic stiffness. Therefore, further study is required.Recognition of the grid structure for member forces is mainly around the following aspects:(1) Consider the in service grid structure node is semi-rigid node.This paper based on vibration frequency truss structure axial force test method study. established the theoretical relations of rod axial force and natural frequency under different constraints.(2) Design different stiffness spring bearing 、hinged bearing、fixed bearing to simulate various rod nodes constraints, and performed experimental study on rod axial force and vibration frequency on corresponding support conditions and study on rod axial force and vibration frequency on full-scale model of truss structure.(3) Based on the theoretical principles of the rod axis force and natural frequency performed MATLAB programming, achieve rod axial force and lever Identification of restraints stiffness numerical analysis of natural frequency, comparative and analysis numerical analysis experimental test values, verify the effectiveness of the method and can applied to engineering practice.