Reserch On Fatigue Of Cutting Platform Framework On 4LZ-4.6 Full-feeding Harvester

Full-feeding harvester is a common rice harvesting machinery. Its working conditions are hard and unstable. Rice and wheat harvesting has timeliness, so the harvester must have the ability for continuing operations. In recent years the task of harvest is bigger and the regional harvester job demand is increasing. The fatigue reliability of harvester becomes the focus. During the harvesting cutting table frame is influenced by the engine, unstable ground, cutter and reel. Fatigue fracture happens frequently. It is necessary to research on the fatigue life analysis of the cutting frame and the fatigue strength should be enhanced.Object of this study is 4LZ-4.6 full-feeding harvester cutting platform framework which is improved from the original model. the fatigue reliability is unknown... In this paper, the method of experimental tests and finite element simulation is combined to finish the study. A scheme is proposed to improve the platform framework’s fatigue strength. The main contents are as followed:1) Pro/E is used to build the model of the framework. The model is simplified for the analysis. The mesh generation is finished in the ANSYS Workbench software so as the static analysis and modal analysis. The results shows that the maximum stress of cutting platform frame which is located near the reel cylinder block is 99.2Mpa.The first four non-zero natural frequencies are [43.16, 61.89, 101.12, 112.75] Hz. The vibration of beam is obvious.2) The test model frequencies which are achieved by the ECON tester are [41.25, 56.95, 105.03, 114.49] Hz. compared the results of the test model and the FEM model the maximum error is 8.8% which is in the finite element analysis allowable range. The reliability of the finite element model has been verified.3) The hazardous areas of the cutting table frame are pointed out. Load signal of the dangerous zone during working in different conditions is collected by the NI dynamic strain signal acquisition system. Least squares method is used to eliminate the drift trend of the original signal. Statistical threshold method is used to detect the singular value. Strain signal is transformed to stress signal. Rain-flow method is used to count the load signal and the rain flow statistic histogram is achieved.4) Material’s S-N curve is created by nCode designlife. Fatigue life analysis is based on the rain flow statistic histogram and fatigue damage accumulative Miner law. Damage histogram of the load signal is achieved. Fatigue life of the platform framework is 2545 h which is below average. The weak part is located on the rear beam. To improve the fatigue strength, the weak part is thickened 4mm, the improved fatigue life is about 2.196×104h and the result meets the requirements.The fatigue research of cutting platform framework in this paper provides a reference for improve fatigue strength.