Hi All,
I have a question regarding modal analysis on Abaqus. I am using untis of kg, N, m s(seconds). in my model. When I conduct the analysis, I get the natural frequency for many modes. Are these frequencies in rads-1 or Hz?
I have looked at the manual of Abaqus, but I can not find an answer for this.
Thanks and Regards,
Dimuth
You can find it in the abacus documentation, there is a Table for the units used. You can search it online or through abacus. However, in FEA, the units must be consistent or in the imperial systems.
Hi,
I have a idea for you. You can model a one beam element or truss element (just Line). You can calculate the stiffness depends on the boundary condition and the model freqeuency of the simple model easily. And then, you can check the results and the units.
Alternatively, you can solve a simple model in another software and compare the results to find out the unit system. For instance you can model the same model which is analyzed in ANSYS (@ link).
Geometry Properties: 100x20x150 mm [W x H x D]
Default Material Properties: Density: 7570 kg m^3 Young's Modulus: 2e11 Pa
Possion's Ratio: 0,3
Boundary Condition: 1 Fixed Face
Mode 1: 734,15 Hz
Mode 2: 2241 Hz
Mode 3: 2846 Hz
Mode 4: 4237 Hz
https://www.youtube.com/watch?v=1qnaRzWuAZI
All, I found that in the data file(afer submission and completeion of job) , proper units are given and both hz and rad/s readings are provided. Thanks
Hi, I think the frequency values are given in Abaqus in rad/s . I always used this value to determine the natural period of a structural member using the relationship frequency =1/period
Hi Haitham, It seems they are in Hz (Cycles/time). Check the data file for confirmation after you submit the job and its complete.
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