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 optimumposition for thewear ring distance is found.Moreover, increasedwear ring stiffness and reduced imperfections increase the buckling load and reduce the bending stresses before the critical load.

Effects of geometrical clearances, supports friction, and wear rings on hydraulic actuators bending behavior

BARAGETTI, Sergio;VILLA, Francesco
2016-01-01

Abstract

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 optimumposition for thewear ring distance is found.Moreover, increasedwear ring stiffness and reduced imperfections increase the buckling load and reduce the bending stresses before the critical load.
journal article - articolo
2016
Baragetti, Sergio; Villa, Francesco
File allegato/i alla scheda:
File Dimensione del file Formato  
PUB - Baragetti Villa - Effect of Geometrical Clearances, Supports Friction and wear rings on Hydraulic actuators bending behavior.pdf

accesso aperto

Versione: publisher's version - versione editoriale
Licenza: Creative commons
Dimensione del file 5.38 MB
Formato Adobe PDF
5.38 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

Aisberg ©2008 Servizi bibliotecari, Università degli studi di Bergamo | Terms of use/Condizioni di utilizzo

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10446/57673
Citazioni
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 12
social impact