One more thing forget to mention. When I have to do modal analysis on the highly damped structure, perhaps I may move the hammer along with the specimen accelerometer in the same time. I'll take some test to verify this thought.
Thanks for Greg's comments. My hammer has 1 lbs weight. Lots of people use 3 lbs hammer in this area, but this small one works.
Just wanted to tell what I got. For the test mentioned above, the reciprocity was so bad and not consistent at all. I moved the test points from "the bad spot" to...
Results
http://files.engineering.com/getfile.aspx?folder=d83c8b66-a7a8-4dce-9ee6-9834548c505f&file=result-magnitude_accePerNewton.PNG
one of charts
http://files.engineering.com/getfile.aspx?folder=78ff0c2d-38b9-4aa1-bc65-88e622840b86&file=chart.PNG...
Attache is model, results and one of charts. The driving point doesn't effect modes, but does effect the magnitude in my test. We also want to know where is max movement againist some frequency...
Great to hear reply. A littl more detail. I made a cylinder model which consists of three layers' circles. The accelerometer was fixed to one point and other points were hammered to get the whole system's FRF, and the driving point showed the max displacement in all cases. How can I fix this?
I did a bump test. In the magnitude chart in FRF, there are few peaks, but none of them corresponds to +90degree in the phase chart, but there is one points to -90 degree.
Can I say the peaks are natural frequency anyways? please help
Hello all,
I am working on a solid model of structural cage with some ribs inside.
Constraints: fixed the first corner-point three movements; fixed the second corner-point two movements; fixed the third corner-point one movement. It does work in ANSYS.
Result: generate very high stress...
