I have a quiestion for you experts out there. I am currentlyworking on a rather large hydralic cylinder, the engineer here hasa spreadsheet for calculating buckling using Euler's formula,mostly concerned with rod dia., so in the spreadsheet we are usingthe extended length of the cylinder & the rod diameter for theentire length of the extended cyl. This 6" bore cyl operates at4500 PSI has an extended length of 201.25". So the spreadsheet sayswe need a 5.16" rod dia to achieve a 2:1 factor of safety. I ranthe cylinder with a 4.500" dia rod in simulation, & then ran arod 5.160 dia. of the extended length to compare against what thespreadsheet was telling us.
In the cylinder I restrained both end clevis's and applied 4500 PSIload to the inside cyl wall & the piston face. The pins werefree to rotate in the clevis bores. & gravity applied, withcylinder in a horizontal position. I was careful to have the wearring supports in the proper locations on the piston & gland tosimulate the actual support.
In the rod simulation I fixed one clevis, applied a load of 127,235lbs to the other clevis, again gravity applied & pins able torotate in the clevis bores. I have attached JPG's of thesimulations, cyinder & 5.160" rod.
Now the question: Is the hydraulic cylinder bucking in simulationreliable enough to say, yes a 4.500" cylinder rod adequate? Orshoud I continue to rely on Eulers formula for column buckling onhydralic cylinders. My though is that the way we are calculatingwith the spreadsheet isn't considering the added strength thecylinder tube adds for buckling considerations.
I ran the rod simulation with a 4.500" dia on the rod also &stresses were near 40,000 psi., so a 4.500 column the ext lengthdoesn't cut it, but a 5.160" does, and the cyl simulation with a4.500" rod is very close to the stresses in the 5.160" rod.
Any thoughts? Are the simulation methods I am using the right wayto approach this?SolidworksSimulation
In the cylinder I restrained both end clevis's and applied 4500 PSIload to the inside cyl wall & the piston face. The pins werefree to rotate in the clevis bores. & gravity applied, withcylinder in a horizontal position. I was careful to have the wearring supports in the proper locations on the piston & gland tosimulate the actual support.
In the rod simulation I fixed one clevis, applied a load of 127,235lbs to the other clevis, again gravity applied & pins able torotate in the clevis bores. I have attached JPG's of thesimulations, cyinder & 5.160" rod.
Now the question: Is the hydraulic cylinder bucking in simulationreliable enough to say, yes a 4.500" cylinder rod adequate? Orshoud I continue to rely on Eulers formula for column buckling onhydralic cylinders. My though is that the way we are calculatingwith the spreadsheet isn't considering the added strength thecylinder tube adds for buckling considerations.
I ran the rod simulation with a 4.500" dia on the rod also &stresses were near 40,000 psi., so a 4.500 column the ext lengthdoesn't cut it, but a 5.160" does, and the cyl simulation with a4.500" rod is very close to the stresses in the 5.160" rod.
Any thoughts? Are the simulation methods I am using the right wayto approach this?SolidworksSimulation
