crush analysis
crush analysis
(OP)
Hello
I am doing some dynamic analyses (with Abaqus/Explicit) to correlate the crushing of an extruded aluminum cylindrical tube with experimental results.
The tube is mounted around a steel rod (assumed rigid) with no clearance. It is supported rigidly at one end and is impacted at the other end by another steel tube (assumed rigid) of a certain mass and speed.
I have managed to (almost) match experimental results in terms of forces, acceleration and displacement, but there is a fundamental difference with the experiments.
Experiments show that the crushing causes the aluminum to fold several times over itself around the tube ONLY ON THE END WHICH IS SUBJECT TO THE IMPACT. The crushing stops halfway through the length of the tube and the remaining part of it remains perfectly straight.
Analyses show that as the crushing progresses the tube folds alternatively AT BOTH ENDS and eventually a straight section is left between the folded ends.
I have tried analysing the tube starting from several different pre-buckled meshes and also from an underformed shape (perfectly cylindrical), but I always come to the same conclusions.
Given the symmetry of the problem I would expect analysis results to be correct. So why the experiments show that the deformation takes place only on the end which is subject to the impact??
Thanks
Gio1
I am doing some dynamic analyses (with Abaqus/Explicit) to correlate the crushing of an extruded aluminum cylindrical tube with experimental results.
The tube is mounted around a steel rod (assumed rigid) with no clearance. It is supported rigidly at one end and is impacted at the other end by another steel tube (assumed rigid) of a certain mass and speed.
I have managed to (almost) match experimental results in terms of forces, acceleration and displacement, but there is a fundamental difference with the experiments.
Experiments show that the crushing causes the aluminum to fold several times over itself around the tube ONLY ON THE END WHICH IS SUBJECT TO THE IMPACT. The crushing stops halfway through the length of the tube and the remaining part of it remains perfectly straight.
Analyses show that as the crushing progresses the tube folds alternatively AT BOTH ENDS and eventually a straight section is left between the folded ends.
I have tried analysing the tube starting from several different pre-buckled meshes and also from an underformed shape (perfectly cylindrical), but I always come to the same conclusions.
Given the symmetry of the problem I would expect analysis results to be correct. So why the experiments show that the deformation takes place only on the end which is subject to the impact??
Thanks
Gio1





RE: crush analysis
Hope this helps!
RE: crush analysis
Cheers
Greg Locock
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RE: crush analysis
Conduct experiment without impact.
VOD
RE: crush analysis
RE: crush analysis
At the moment both ends are modelled in the same way, i.e. the only restraint is contact with friction. I will now try to clamp the non-impacted end as suggested by JulianHardy.
I had also already planned to run the experiment quasi-statically, as suggested by VoyageofDiscovery. Of course will re-run the analysis to match these conditions
I am assuming the other cylinder to be rigid because it is made of hard steel; i.e. much stiffer than Al. Perhaps though assuming it to be rigid is a bit too much. Will try this one too GBor.
Will update with results as soon as I get them. I put my money on JulianHardy's tweak, although don't know how much realistic his assumption would be
Thanks
Gio1
RE: crush analysis