natural frequency issue
natural frequency issue
(OP)
hi all,
trying to validate a model that has been testing in real life to gain the first natural frequency.
I know what the results should be and for what mode.
but any attempts to create a frequency job in abaqus to output the same results isn't successful.
its an imported igs file, ive followed various tutorials with my own properties bc's etc.
the main problem is the output results in abaqus are very small in terms of Hertz... whereas the real life test was 5kHz which is proven.
Any common issues I should look out for with solid models and natural frequency jobs?
if any pics or further info is require happy to supply! :)
Thanks in advance.
trying to validate a model that has been testing in real life to gain the first natural frequency.
I know what the results should be and for what mode.
but any attempts to create a frequency job in abaqus to output the same results isn't successful.
its an imported igs file, ive followed various tutorials with my own properties bc's etc.
the main problem is the output results in abaqus are very small in terms of Hertz... whereas the real life test was 5kHz which is proven.
Any common issues I should look out for with solid models and natural frequency jobs?
if any pics or further info is require happy to supply! :)
Thanks in advance.





RE: natural frequency issue
- have you specified correct boundary conditions,
- are your material properties correct, have you used a consistent set of units (I would recommend kg, m, N and their combinations),
- assuming that your geometry is correct, is the mesh type / density adequate,
- check if ABQUS has given any warning messages for further information.
RE: natural frequency issue
im only to the point of asking here now as my lecturers and tutors cannot even help me anymore.
the part is in the image attached with these conditions..
the boundary conditions are encastre in initial step. at either end of the part in the through holes
material props (6082 Aluminium) are entered like below:
density 2700
youngs mod: 70000
poisons: 0.33
yield: 310
meshed at a seed of 4
part drawn in solidworks in MMGS
no error messages from abaqus either.
RE: natural frequency issue
I suggest you use as follows:
- length - m
- density - kg/m^3
- Young's modulus, stress - N/m^2
or, alternatively:
- length - mm
- density - tonne/mm^3, i.e. 2.7E-9
- Young's modulus, stress - N/mm^2
RE: natural frequency issue
turn out that the density was causing some issues.
some trial and error with the step manager and I have my results!
Thanks Bkal!