Research On Geometrical Nonlinearity Stability Of Truss Boom

According to the development of manufacturing and the use of high-quality and high-strength steel, lattice boom continues to be taller and softer. As major bearing component, the boom system may lose stability before strength failure, which makes the overall stability of boom system earn more and more attention.The current status of geometrical nonlinearity and stability at home and abroad are outlines in this paper. The insufficient of nonlinear stability analysis in truss jibs is also mentioned. The theory of linear and non-linear finite element methods are introduced and the stability theory based on that is proposed. The influences of second-order effect considering large deformation of statically indeterminate beam are described. Considering the influences of length, lifting radius, initial deformation and side load, the ultimate strength and unstable mode of truss boom of 1900/200t stationary slewing crane and 280t crawler crane are researched in this paper. The instable load and the deformation under tensile load can be obtained by their load-displacement curves. Beyond that the function of different component can be presented clearly and that is important for designing.The main research contents and achievements of this paper are as follows:(1) By analyzing load-displacement of different conditions, the impact of length, lifting radius, initial deformation and side load on the ultimate load-carrying capacity of truss boom are studied.(2) The linear stability analysis and the non-linear one are compared in this paper. Through that the advantages of non-linear stability analysis are proved and the necessity of geometrical nonlinearity stability of truss boom is proposed.(3) The actions of every part in truss boom on instability process are explained by researching the load-displacement curves of different nodes which are useful in designing.