Misalignment effects on the load capacity of a hydraulic cylinder

Gamez-Montero, Pedro Javier; Salazar, Edgar; Castilla, R.; Freire, Javier; Khamashta, M.; Codina, Esteve

doi:10.1016/j.ijmecsci.2009.01.001

Cited by 44 publications

(35 citation statements)

References 3 publications

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“…The model presented in [10] is here modified considering a partial detachment of the wear rings from the internal surfaces of the cylinder and of the gland. In [11], the effects of misalignment are addressed, substantially confirming the validity of the theoretical approach presented in [9,10]. The consideration by Flügge [6], that the internal pressure resulted in negligible effects, is also confirmed in [11].…”

Section: Mathematical Problems In Engineeringsupporting

confidence: 65%

“…The models presented in [8][9][10] have been recently adopted by Gamez-Montero et al [11,12], which inserted the contribution of the actuator own weight and the effect of the cylinder's internal pressure on the buckling load and bending behavior. The model presented in [10] is here modified considering a partial detachment of the wear rings from the internal surfaces of the cylinder and of the gland.…”

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

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Effects of Geometrical Clearances, Supports Friction, and Wear Rings on Hydraulic Actuators Bending Behavior

Baragetti

Villa

2016

Mathematical Problems in Engineering

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Hydraulic actuators are commonly adopted in machines and structures to provide translating forces with significant magnitudes. Although their application dates back to the industrial revolution, their bending behavior under compression is typically addressed by simple Euler's instability analysis on the rod, neglecting effects such as the cylinder inertia and stiffness, the presence of contact elements in the cylinder-rod junction and on the piston, geometrical misalignments and imperfections, and friction moments at the support. Such simplifications lead to unjustified reduced critical load calculations on the component. In the present paper, a complete mathematical formulation, which accounts for such effects, is presented and validated against experimental data. A numerical sensitivity analysis is conducted, to assess the contributions of initial rectilinear imperfections, wear rings stiffness and dimension, and supports friction on the actuator's limit buckling load and bending behavior under compression. Results are presented, including the effect of the cited parameters on the buckling load, providing a reliable tool for the mechanical designer. In particular, an optimum position for the wear ring distance is found. Moreover, increased wear ring stiffness and reduced imperfections increase the buckling load and reduce the bending stresses before the critical load.

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Section: Mathematical Problems In Engineeringsupporting

confidence: 65%

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

Effects of Geometrical Clearances, Supports Friction, and Wear Rings on Hydraulic Actuators Bending Behavior

Baragetti

Villa

2016

Mathematical Problems in Engineering

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“…This misalignment is judged unavoidable for the fixation method used, being typical of usual assembly tolerances or by wear of guide rings. Initial imperfection due to misalignment in the interface between cylinder tube and piston-rod creates an imperfection angle between piston-rod and cylinder tube centroid axis, which evolves depending on the piston stroke [19].…”

Section: Radial Displacementmentioning

confidence: 99%

Experimental Study of 3D Movement in Cushioning of Hydraulic Cylinder

2017

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A double acting cylinder operation has been fully monitored in its key functional parameters, focused on characterization of end-of-stroke cushioning and starting phases. Being the cylinder performance reliant in the piston constructive geometry, the number and location of piston circumferential grooves is a significant parameter affecting the internal cushioning system performance. An eddy current displacement sensor assembled in the piston allows assessment of piston radial displacement inside the cylinder tube, which is directly related with the studied operating phases. Due to such 3D displacements, the piston becomes as an active and self-adjusting element along the functional cycle of the cylinder. Mechanical joints orientation and operating pressure are also relevant parameters affecting piston radial displacement and, thus, the cushioning and starting performance. Computational Fluid Dynamics (CFD) results confirm the observed functional role of the perimeter grooves; the flow and pressure distributions, where develops a significant radial force, are also in accordance with the registered radial displacement.

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“…GUO Ying-long et al [1] put forward two sections pressure bar mechanical model and the calculation formula of the buckling critical load is derived taking into account the reactions between the piston rod and the hydraulic cylinder and the stiffness of the hydraulic cylinder. Considering the initial deflection of the hydraulic cylinder and the piston rod, self-weight, and the friction moments at the two hinge joints, P J Gamez -Montero et al [2][3] derived the calculation formula of the buckling critical load and verified the variation law of the buckling critical load with the initial deflection. The results of the tests show that the influence of the friction moments cannot be ignored when the clearance between the pivot and sleeve is enough small.…”

Section: Introductionmentioning

confidence: 99%

Stability analysis of large slenderness ratio horizontal hydraulic cylinder

Xiong-Hao

Shi

Shuang-Yang

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. An improved two sections pressure bar method (ITSPBM) was presented to analyze the stability of the large slenderness ratio horizontal hydraulic cylinder. The friction moments, the bearing reactions at the two hinge joints as well as the clearances between the piston and the inner wall of the cylinder were taken into consideration. The result shows that the stability safety factor is 6.20. Meanwhile, in the finite element model of the horizontal hydraulic cylinder, the nonlinear friction force and clearances were involved. The result reveals that the stability safety factor is 9.24. Through comparing the results of the ITSPBM, the traditional two sections pressure bar method (TTSPBM), the finite element method (FEM) and the method in NB/T 35020-2013, it suggests that the stability of the large slenderness ratio horizontal hydraulic cylinder meet the actual engineering requirements and the friction moments at the two hinge joints can extremely enhance the stability. IntroductionUnder the condition of large axial load, the stability problem of large slenderness ratio horizontal cylinder is critical for the safety and reliability of the whole structure design. As for the large slenderness ratio horizontal hydraulic cylinder, it is simplified as equal section mechanical model in engineering design to analyze the stability according to the Euler formula. In this algorithm, the hydraulic cylinder and the piston rod are fixedly connected. The clearance between the piston rod and the guide sleeve, the friction moments at the two hinge joints and the bearing reactions are not considered. The calculation results cannot fully reflect the deflection and buckling characteristics of the large slenderness ratio horizontal hydraulic cylinder. GUO Ying-long et al [1] put forward two sections pressure bar mechanical model and the calculation formula of the buckling critical load is derived taking into account the reactions between the piston rod and the hydraulic cylinder and the stiffness of the hydraulic cylinder. Considering the initial deflection of the hydraulic cylinder and the piston rod, self-weight, and the friction moments at the two hinge joints, P J Gamez -Montero et al [2][3] derived the calculation formula of the buckling critical load and verified the variation law of the buckling critical load with the initial deflection. The results of the tests show that the influence of the friction moments cannot be ignored when the clearance between the pivot and sleeve is enough small. Under the actual working conditions of the hydraulic cylinder system, the axial pressure exerted by the oil in the hydraulic cylinder applies on both ends of the piston rod. Based on the mechanical model, WU Ting-ping [4] considered the bearing reactions existing at both ends of the hydraulic cylinder and calculated the stability of the

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Misalignment effects on the load capacity of a hydraulic cylinder

Cited by 44 publications

References 3 publications

Effects of Geometrical Clearances, Supports Friction, and Wear Rings on Hydraulic Actuators Bending Behavior

Effects of Geometrical Clearances, Supports Friction, and Wear Rings on Hydraulic Actuators Bending Behavior

Experimental Study of 3D Movement in Cushioning of Hydraulic Cylinder

Stability analysis of large slenderness ratio horizontal hydraulic cylinder

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