Traction Frame Fatigue Reliability Analysis Of The Grade Working Device

Grader was important earthwork construction machinery;the blade working device was among the most basic,and the most direct working mechanism.The grader tractor was an important component for carrying and connecting adjacent components in the blade working device.In the actual operation,the fatigue failure analysis of the tractor was mainly based on the daily work experience.The fatigue reliability of the tractor was analysed with the numerical simulation and software simulation.The main analyses as following:(1)The structure of the grader tractor and the grader operating load were analyzed.The components kinematic relationship of the working device was obtained and the working device was simplified.In order to accurately analyze the traction frame loading,the blade operating loads were been equivalent to the tractor based on space description and coordinate transformation theory.(2)Four typical operation modes were analyzed.Three-dimensional model of the traction frame was established with 3D software Pro/Engineer.Based on the seamless connection between Pro/Engineer and ANSYS,the traction frame 3D model was inported to Mechanical APDL.The static strength of tractor under four typical operation modes was analyzed based on the finite element theory.Through the trial and error method,the horizontal limit load of the blade was acquired when the tractor was in the yield limit state.(3)The operating conditions were numerically simulated based on the numerical analysis software MATLAB and the current actual operating conditions statistical data.With the rain flow counting method,the two dimensional loading spectrum of the tractor were constructed,and the parameter estimation and hypothesis test of the loading spectrum were carried out.The equivalent two-dimensional loading spectrum was been equivalent to one-dimensional loading spectrum with the equal life method which could be used for fatigue reliability analysis.(4)The traction frame body was selected as the blade obliquely scraping at the maximum cutting depth.Based on the finite element fatigue analysis theory,the fatigue reliability analysis of the tractor body was carried out in the Fatigue module of Mechanical APDL with the equivalent one-dimensional loading spectrum and the P-S-N curve of the traction frame body material.