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Corrosion or contamination of flexible joints of a telescopic hydraulic cylinder may cause an increase of movement resistance in these places. In this work the influence of mounting rigidity on the strength of a telescopic hydraulic cylinder is under consideration. Buckling criterion and the strength of cylinder barrels (material effort) were included due to analysis. Boundary value problem concerning the stability of the system was formulated on the basis of the static stability criterion. Lame's theory for thick pipes were used for determination of destructive load from the viewpoint of the material effort. Numerical simulations were performed. The results specifying the influence of mounting rigidity on stability and strength of cylinder barrels were presented by using non-dimensional parameters.

The paper presents the boundary problem of the stability of a telescopic hydraulic cylinder subjected to a generalized load with a force directed to the positive pole. The boundary problem was formulated on the basis of the Hamilton principle. Numerical calculations were carried out, taking into account the influence of the parameters of the load heads (radii of loading and receiving head, length of bolt). On the basis of the numerical calculations, regions of load heads parameters were presented, at which the load bearing capacity of the analysed telescopic hydraulic cylinder is the largest from the buckling standpoint.

In this work, transverse vibrations of the piston rod of a hydraulic cylinder, which is connected with a system characterized by its own high weight, e.g. a tank gate, were considered. The case is considered when the actuator is fully extended and the piston rod is not affected by external static axial forces (the actuator acts in a horizontal position, as a result of which the weight load at its end does not compress the piston rod). To analyze this issue, a beam model was developed taking into account the longitudinal inertia of the mass element associated with one of the ends of the system. The boundary problem of vibrations was formulated using the Bernoulli–Euler theory. Taking into account mass inertia (directed longitudinally) results in the appearance of nonlinear terms in equations describing the behavior of the system during vibrations. The small parameter method was used to finally formulate the problem of nonlinear vibrations. In the description thus adopted, the vibrations of the considered system strictly depend on the dead weight of the gate valve as well as the amplitude of the piston rod oscillations. The results of numerical simulations are presented taking into account the impact of piston rod stiffness and stiffness of mounting to the valve on its vibrations. In the considered range of masses, the effect of amplitude on the value of the natural frequency of the system is presented. Theoretical considerations have been confirmed to some extent by experimental studies.