Buckling Behavior of Horizontal Hydraulic Cylinder Articulated at Both Supports

摘要

The existing critical buckling load calculation methods of horizontal hydraulic cylinder failed to fully reflect the initial boundary conditions and some critical influence factors, resulting in an unjustified critical buckling load. A new method to analyze the buckling behavior of the horizontal hydraulic cylinder articulated at both supports is developed on basis of large deflection theory and Timoshenko beam theory. Friction at supports, self-weight and initial misalignment by clearances are taken into account. Friction moments of supports are built according to Hertz contact theory. Bending stiffness of cylinder-rod junction is figured out in terms of elastic deformation theory. Runge-Kutta and Newton-Raphson method are used in numerical calculation for the critical buckling load. Practical calculation and stability test are carried out to verify the necessity of considering large deflection and shear effect in the proposed method. Experimental work shows the critical buckling load by the proposed method can well match to that by stability test with 0.55% deviation. Moreover, the numerical calculation results demonstrate that the friction moment of the support at piston rod end is crucial for the buckling behavior. The critical buckling load rises increasingly as the friction coefficient mu(2) rises. As the friction coefficients mu(2) increases from 0 to 0.020, the rise rate of critical buckling load increases from 1.782% to 8.055% per 0.001. And the clearance at cylinder-rod junction is a minor factor on the critical buckling load. As the clearances increase by 10 times, the critical buckling load decreases by 3.542%.