Iterative Method Research On Lifting Capacity Of All-Terrain Crane

Lifting capacity reflects the integrated lifting capacity of crane, so calculating lifting capacity accurately and quickly is very important to the design of crane, give full play to hoisting equipment ability and reduce risk.The boom of all-terrain crane has a lot of kinds of combination, such as telescopic boom, fixed jib, luffing fly jib, telescopic boom superlift, luffing fly jib boom superlift. There are hundreds of different boom length and amplitude in every combination. Iterative algorithms are key to calculate the rated lifting load on each condition. Traditional method of calculation is the constant increment method and the bisection method. The number of calculation from given the initial load to obtain the rated lifting load is too large, Initial lifting load, increment and other factors have great influence to calculation speed. In this paper, proportional iterative algorithm, modified proportional iterative algorithm and Lagrange iterative algorithm are presented which based on constant incremental method and bisection method. Because has used each the iterative calculation result, the calculation efficiency has been improved significantly, also meet the engineering calculation precision requirements.This paper is devoted to researching the telescoping boom with single cylinder and Pinning System of all-terrain crane. The theory calculation such as structure strength of boom have been researched according to "Design Rules for Cranes", "Construction Crane", " metal structure of lifting transporters". Using by linear and geometric non-linear finite element theory, carry on the iterative computation to obtain the rated lifting load on each condition. The specific research works are as follows:(1) In this paper, the telescopic crane boom system are simplified as a series of space beams and links, imposing equal constraints according to the interaction between the one part and the others. The external load are analyzed, geometric non-linear finite element method is used to calculate deformation of element and node force on a given condition, summarizes traditional lifting capacity calculating method to calculate complex stress. Theoretical explanation and comparison with ANSYS results prove that simplified model of all-terrain crane and finite element computational process are correct.(2) Using the constant increment method, bisection method, proportional method, modified proportional method and Lagrange mixed method iterative calculating the rated lifting load, analysis these influence which the initial load and error factors impact on calculation efficiency and the convergence. Finally, in accordance with the boom length on polynomial fit to calculate the whole lifting capacity table. (3) The application of linear theory and geometric non-linear theory are obtained according to linear and non-linear results of different boom length and different luffing angles. By comparison with displacement and node force of element which calculate using the method presented in this paper and ANSYS results, integrated results and the sample data, these results verify this method is reliable to calculate lifting capacity of telescopic boom crane and the results have a certain accuracy.