×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Long-Stroke Hydraulic Cylinder Mid-Length Support Question

Long-Stroke Hydraulic Cylinder Mid-Length Support Question

Long-Stroke Hydraulic Cylinder Mid-Length Support Question

(OP)
I've got an unusual design issue where I need to use a spherical eye to spherical eye single-stage hydraulic cylinder operating primarily under compressive loads. I cannot mount it with trunnions or spherical cap at the gland, but I can support it against buckling (vertical installation, rod-down) if needed. Stroke is 15 ft.

The cylinder manufacturer says that there is a 4:1+ FoS on buckling, but I'm not so confident that it's really that high. For the sake of redundancy, is it possible, or for that matter advisable, to add lateral support (can make that very stiff) by putting either a loose collar around the gland end of the tube (1/2" clearance all around 14" OD), or for that matter, a tight one, though flexure in the installation may make it advisable to let the cylinder 'float' inside the collar.

This isn't just a straight Euler buckling problem, as the tube has a moment of inertia around 3.5 times that of the rod, and the tube isn't under compression in the normal sense.

Anyone have any thoughts?

RE: Long-Stroke Hydraulic Cylinder Mid-Length Support Question

I always use an internal stop collar in situations like that. It just basically reduces the effective stroke and stiffens the cylinder in the full extended position. You would probably use a cylinder built for a 17' or 18' stroke with an internal stop collar that limits it to 15'. Can you do that?

RE: Long-Stroke Hydraulic Cylinder Mid-Length Support Question

(OP)
That's already part of the design, but I'm still concerned about the extended length. I just downloaded the NFPA T3.6.37 R1-2010 (Method for Determining the Buckling Load), so I'll experiment with that. The standard does take into account the stop tube length, by the way.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources