Mechanics Analysis Of Working State Of Active Arm Frame Of Loader's Working Device

With the development of modernization, the industry of engineering machine has gained huge promotation,higher requirement has been needed for the structure of engineering machine,such as high bearing capacity,long fatigue life,and low production cost .On the presupposition of meeting its strength and stiffness,optimal design should be obtained. Working device of the loader is one of the main bearing parts,studying its practical bearing circs will provide academic gist for the designation of loaders. Knowing the bearing circs of working device,you can make the finite element method analysis and structural intensity analysis,making right choose for machining material,machining method and structural shape.The strongpoint of material mechanics is you can shortcut gain the resultant force of the location(especially the boundary area)to do farther particulary analysis.However,there is big difference with the fact because of the hypothesis in geometric modeling and mechanical modeling. The finite element model can be build according to its main character by the finite element simulation to analyze its stress and distortion completely and exactly.Beating out the bearing circs of working device,baced on the loader's working mode,working process and the outside force to load,calculating the bearing circs of each component of working device to do the finite element analysis. At the same time, calculateing the internal force of each component by material mechanics to compare with the finite element analysis result. Building the figure model according to its main character by UG for the next finite element analysis.Active arm is one of the main parts of working device,its bearing circs is complex and its deadweight is large. In the past,damage has occurred in loaders in home and overseas. In this dissertation,we first choose the most bearing case to do static structural analysis,the stress,strain and displacement ditributions of wholly active arm are obtained. Changing the place of active arm to do the same analysis,we choose four cases to analyze: (1)the angle of active arm and the floor is 30;(2)the angle of active arm and the floor is 15;(3)active arm is in the unload position;(4)the loader unloads. Analyzing the results of the four cases ,we know the place of the maximum of stress, strain and displacement of active arm in the whole working process,which may be used as reference in the optimization of active arm.Noting the place and numerical value of the maximum of stress, strain and displacement,the static load spectrum is obtained ,namely time-stress load spectrum, time-strain load spectrum and time-displacement load spectrum. Understanding the change of place of the maximum,we can know the bearing circs of the easy destroyed position much more clearly.At last,estimating the fatigue life in advance based on the finite element analysis results and fatigue damage accumulation theory,we can find problem before breakage and repair it to reduce fatigue rupture accident. At the same time,it is of great meaning for the design, produce, checkout and manager of loader.