| All-terrain crane has a wide usage in factories, docks, construction sites, mines and other fields. The combination of main boom and tower jib has been widely used for large lifting height and workable radius of the crane. The lifting weight under large lifting height and workable radius seems to be an important indicator to measure the crane. Since the normal lifting capacity is defined by the rating weight under a certain length of boom and designated workable radius, then the rating weight can influence the workable radius. Therefore, the deformation effects should be considered in design process.Some researches have been studied on the calculation of lifting capacity and deformation, whereas there is no in-depth explotation on the influence of lifting weight on the deformation. In other words, no papers discuss the lifting weight influence under the deformation when determining lifting capacity.A certain500t all-terrain crane is taken to study, based on the linear and nonlinear theories, laws of the influence of different theories on the main boom and the tower jib working conditions are all considered. Specific research works are as follows:(1) The working conditions and principles of all-terrain crane are studied, and the main-boom and the tower jib working conditions are selected out. The models of every part of the boom are simplified and the FEA models are set up with fully understanding the boom structure. A comparison is made from the simplified and the complicated model to verify the correctness of the simplification in this thesis.(2) Parameterized modeling is investigated. With APDL provided by FEA software ANSYS, a proportional iterative method is used in program to solve the maximum lifting weight, tending to realize various cycle conditions under linear and nonlinear theories.(3) MATLAB is used in processing the FEA results by researching different initial luffing angle, length of the main boom and the length of the tower jib to obtain the laws of influence of linear and nonlinear theories on deformation of the boom.The study indicates that with the increase of the length of the main boom and the tower jib and the initial luffing angle, the influence of stiffness linearity and nonlinearity on deformation grows larger. As a result, when the boom is comparatively short or the initial luffing angle is small, calculating efficiency can be improved by the replace of nonlinear model by using the linear one. The results provide a reference for simplifying the finite element model of the same type boom for all-terrain crane. This still suits for its designing and analyzing. It can be a more accurate and reasonable method for lifting capacity calculation. |
