| The SQ Z4500 B truck-mounted crane is a kind of lifting equipment with a folding-arm.It is generally installed on a truck for self-loading,unloading and transportation of goods.It can be used as a substitute for smaller and middle range mobile cranes.The research topic of this thesis comes from a cooperation project between Yanshan University and a domes tic crane manufacturer aiming to improve the crane structure design and reduce the weight of the car body.First of all,a parametric finite element model has been established based on the 3-D Pro-E geometric model of the crane truck chassis.Rational boundary conditions have been applied to the finite element model.Static analyses have been carried out for typical loading conditions.Also,the stress tests were carried out on the prototype of the truck-mounted crane and the test results were found to be in good agreement with the finite element model predictions.This shows that the accuracy of the finite element model developed is promis ing.Using the topology optimization module and the sub-model technique in AN SYS,the shape of the side welding panels of the outriggers of the crane were topologically optimized.The maximum equivalent stress of the side panels was reduced by 106 MPa compared to the original design.The cover area of the welding side plate was reduced by 31.3%.The thicknesses of the steel plates of the chassis were optimized as well under the constraint conditions of its structural rigidity and strength requirement.A more reasonable plate thicknesses combination was obtained.By doing so,the total weight of the chassis was reduced by 11.6%.The material ut ilization rate was significantly improved.The topology optimization method based on sub-models proposed in the thesis can substantially reduce the computing times and this can be considered to be a new method for implementing more effic ient optimization designs of complex plate welding structures of construction machinery. |
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