Optimizing And Test Verification Of The Fatigue Of Key Components Of Forklift Based On The Driving Cycle Condition Proposed By VDI

The research on a certain type of 3.5t forklift of fork carrier and fork in 1 million fatigue fracture and too long fatigue life of a type 1.4t storage truck frame fatigue life too long problems were carried in this paper.On the basis of the establishment of finite element mode of the fork carrier and fork and the initial of storage truck frame,the fork carrier was optimized by the topology optimization method,the fork was optimized by the shape optimization method and the initial storage truck frame was optimized by reducing the thickness.The static analysis and modal analysis of the optimized fork carrier and fork were carried out,and the static analysis was carried out on the storage truck frame before and after optimization.Then according to the static calculate results and the load spectrum measured by Association of German Engineers cycle,the fatigue simulation analysis of the finite element model of the fork carrier,fork and the storage truck frame before and after optimization on the basis of the fatigue theory of Miner and Goodman mean stress correction method was done.At last,the test verification was done.The main research contents of this paper are as follows:1)The fork carrier,fork and storage truck frame were optimized.The initial model of the fork carrier is established in the Inspire solidThinking software.The bassic model after optimized was obtained by the topology optimization.According to the basic model and combining with the actual needs,the reconstruction model of the fork carrier was obtained in the UG software.Under the OptiStruct module of the HyperMesh software,on the basis of establishing the finite element model,the optimization method of shape optimization was used to optimize the structure of the fork,so that the fatigue life could be improved under the condition of not increasing the quality.2)The modal analysis of fork carrier and fork were done.The modal analysis of fork carrier and fork were done in HyperMesh software.By setting parameters,the natural frequency and vibration mode of the first 16 order modal of fork carrier and fork were obtained.By this way,if it was related to the road excitation and the power system of the forklift resonance was clear.3)The static analysis of fork carrier,fork and storage truck frame before and after optimization were done.By the static strength analysis of fork carrier,fork and storage truck frame in the software of HyperMesh before and after optimization,static characteristics were researched,stress distribution were understood,strength was checked,and finite element analysis results were offered to the fatigue life analysis.4)The fatigue life of fork carrier,fork and storage truck frame before and after optimization were analyzed.Based on Miner fatigue cumulative damage criterion,the S-N curve of each component material were selected.The fatigue life of fork carrier,fork and storage truck frame before and after optimization were analyzed by using the load spectrum measured under the actual cycle of VDI and the nCodeDesign Life software.5)Test verification of fork carrier,fork and storage truck frame were done.Based on the load spectrum measured by the actual cycle of VDI as the input load spectrum of the fatigue testing machine,the fork carrier frame,fork and storage truck frame after optimization were tested and verified.By the test verification of the optimized fork carrier frame and fork,fork carrier frame fatigue life after optimization was 1139433 times and it was 3.48 times of that before optimization.The fork fatigue life after optimization was 1199153 times and it was 1.88 times of that before optimization.It showed that the enterprise one million times requirements for fatigue were met by the optimized fork carrier frame and fork.After 1 million fatigue test,no cracks were found on the storage truck frame.It showed that the enterprise requirements for fatigue were met by the optimized storage truck frame.The quality of the storage truck frame was reduced by 23.06 kg.Thereby,the cost of the product was reduced.By the optimization method of simulation and test combined,the product development cycle could be effectively shorten and the product competitiveness in the fierce market environment could be improved.The certain reference significance would be offered to the design and optimization of other vehicle parts.