Telescopic Hydraulic Cylinder Buckling

[mcarmen]

I am looking for relevant design codes and standards dealing with the design of a hydraulic telescopic cylinder.

Specifically looking for details on cylinder buckling and methods of calculation.

 

[Tmoose]

http://www.strautmann-hydraulik.de/en/products/technical-information/#c876

Down the page about 80%.

They seem to be primarily concerned with the rod, not the assembly

 

[3DDave]

You need to contact the intended or present maker of the telescopic cylinder. They don't behave like simple columns and are very sensitive to internal construction. Here's one $28 paper on the subject;

http://www.scientific.net/KEM.417-418.281

If it was of more interest, I'd buy it. Also this

http://www.eng-tips.com/viewthread.cfm?qid=290160

On the Buckling Behaviour of Telescopic Hydraulic Cylinders

Abstract

Telescopic cylinders are generally employed as linear actuators, when the desired moving span is several times the length of the closed device, like in cargo trucks lifting applications, for instance. During the active phase of the actuation, hydraulic power is normally used to feed pressu-rized fluid inside the cylinder, thus providing the progressive extension of the cylinder elements and the required operative axial thrust. In this condition, therefore, cylinders must bear external compressive loadings in an increasingly slenderness configuration, which can give rise to buckling failures. In this study, experimental measurements of the limiting axial loadings of telescopic cylinders, in full extended conditions, have been performed both in laboratory and during real operations on the field. The strains of the material in the critical sections and the lateral deflections of the tested structures have been recorded as a function of the applied loads. The results of this investigation are presented and discussed, in order to identify the signals of incipient buckling and find out the ultimate load carrying capabilities of this kind of components.

 

[gruntguru]

If you are clever you will design the mechanism so the design axial force decreases with extension. This may be necessary from a hydraulic standpoint anyway, since the hydraulic force decreases stepwise at the changeover to smaller diameter stages.

je suis charlie