Establishment Of Fatigue Test Load Spectrum Of Excavator Boom And Its Fatigue Life Prediction

In this thesis,combined with the National Science & Technology Pillar Program " Earth-moving machinery fatigue and reliability key technology research" during the 12 th Five-year Plan Period,the excavator XE215 G of Xu Zhou Construction Machinery Group is taken as the research object.The load time course of the boom is obtained by the test method,then the fatigue test program loading spectrum of boom was compiled and the fatigue life of boom was predicted at the same time.All above making a complete excavator working device fatigue load spectrum preparation and life prediction of research methods to improve the level of domestic excavator independent research and development.The main contents of this paper are as follows:According to the characteristics of the load condition of the excavator,the actual load test scheme of the excavator working device is put forward,and the noise stress data of the cross section are measured by wavelet denoising.Through the measured section stress to calculate the hinge load,then get the boom of the external load time course.Based on the design of the boom acceleration fatigue test scheme,simplify and equal the external load component of the boom hinge,and the simplified load component is analyzed by rain count and combined with the "fluctuation center method" to get the eight-level program load spectrum.Then,based on the equivalent conversion theory of equal damage,the fatigue test loading spectrum of multi-mode synthesis is compiled.According to the five-step method of fatigue simulation analysis,the five-block flow chart of fatigue life analysis is established based on the simulation software nCode Design Life: the finite element model of the boom is established and the stress distribution result is obtained,The load information is input,the material parameters are set,the fatigue engine parameters are set,the result is displayed.Finally,the fatigue life spectrum of the boom and the first fatigue damage area are obtained,then the simulation results are analyzed.The extraction scheme of the actual load of the excavator boom and the preparation of the test load spectrum of the multi-mode synthesis in this thesis are the important basis for the anti-fatigue design and fatigue test,which provides theoretical guidance and experience for the further development of the load spectrum of the excavator working device.At the same time based on nCode Design Life fatigue simulation for the boom fatigue life prediction,which opens up a new way.