Sectional Optimal Design Of Telescopic Boom Of All Terrain Crane

Crane is a fetch machinery,with the development of society various types of crane appearceaselessly,its design and craft tend gradually to standardized. Telescopic boom is one of themost important structure of all-terrain crane, it is the main structure of all the force structure, soin the practical work we should consider its stiffness, strength and stability. So the size of thetelescopic boom section becomes very important.Telescopic boom is very important structure of all-terrain crane, which usually accounts forabout18%of the weight of the whole crane, and this proportion of a large tonnage all-terraincrane is even greater, which reduces the performance of the crane. Therefore, on the premise ofcomplying with the requirements, we can use the optimal design approach to optimize the size ofthe boom structure, reducing the weight of the entire structure, which play a key role in thewhole telescopic boom design of large-tonnage cranes.Before the optimal design we should write the ANSYS command stream file of thestructural parameters program of all-terrain crane boom. When establishing the finite elementmodel, the structure of arm tube and the wire use BEAM188element to simulate, the structure ofluffing cylinder using LINK8element, and the slide between every two arms using MPC184element. After the establishment of the finite element model, you need to impose boundaryconditions, ie the hinge point of the main boom and the hinge point of luffing cylinder needrestrain its translational degrees of freedom in three directions, while the hinge point of thesingle wire makes full restraint; there are load weight, lifting, wind load, side load and rotaryinertia loads. In addition, the large stress location in the structure need establish control sectionto facilitate extraction of the calculation results.This paper uses two methods to optimize the telescopic boom section size of all-terraincrane.Firstly, using the ANSYS optimization algorithm optimizes the telescopic boom structure.In this paper taking into account the accuracy of its optimization results, so we should chose touse the first order optimization algorithm to optimize. When using ANSYS softwareoptimization module to optimize the cross-section of telescopic boom, the basic structure form ofall-terrain telescopic boom crane is unchanged, it should always maintain a U-shapedcross-section, the cover thickness of every arms and U-shaped cross-section dimensions areconsidered as design variables, when all-terrain crane normally work,control section the maximum Von Mises stress of the control section are considered as state variables, the total massof the entire telescopic structure is considered as the objective function. According to themanufacturer requirements, we choose the range of design variables when optimizing, and thencalculate the optimal value by the first-order algorithms.Secondly, we use genetic algorithms to optimize the section of the telescopic boom. Thisarticle uses the integer coded form of genetic algorithms, we put new individuals and parentindividuals all together to form a new population by the genetic operators, and calculate eachindividual’s fitness, choose the N individuals of the best fitness form the next generation (N isthe number of the population), this will ensure that some good individuals of the parents can beinherited. Specific calculation procedures are as follows: compile the program of geneticalgorithms using MATLAB software, the genetic algorithm fitness values are calculated bycalling ANSYS, every fitness values are stored in a file, in order to facilitate the calling ofgenetic algorithm program. we should give the maximum iterations number of the program, withthe number of iterations increasing, the individuals of the population tends to keep the best.Finally, According to the optimization results of the two methods, we can see that the entireweight of the telescopic boom structure reduces a lot after be optimized. Genetic algorithms andANSYS first-order algorithm are feasible in the optimization of cross-section telescopic boom,this article provides a reference for all-terrain crane boom structure reducing weight, based onthe existing model of all-terrain crane, it can provide a reference for designing the greatertonnage crane by optimizing the cross-sectional dimensions.