- #36
minger
Science Advisor
- 1,496
- 2
OK, so based on what you told me I threw the shaft quickly into the rotordynamics program that we use. Here is the geometry
The coupler on the right, Station 7 is on another "level" in the program, this basically will assume that the coupler is completely rigid. In the real-world it's not, but unless we have a number to put in, that's the best I'm going to be able to do.
The left spring is a bearing, bearing by definition only, I realize this is actually a fit. I have made the bearing very rigid in the lateral directions, essentially cantilevering the rest of the shaft off of it.
Hopefully, the rest of it looks good. The first few mode shapes that the program computes are:
The table of computed critical speeds are:
If you want the data output file, then it's located at:
http://www.eng.utoledo.edu/~mheminge/shaft_test.OU2 The file is open-able in wordpad, it lists the station properties, displacements, energy distributions, etc. Well, hopefully this helps, moreso, hopefully it matches what you tried to compute analytically. If there is any small changes in the inputs, then let me know and I'll try and find time to change it and rerun it.
The coupler on the right, Station 7 is on another "level" in the program, this basically will assume that the coupler is completely rigid. In the real-world it's not, but unless we have a number to put in, that's the best I'm going to be able to do.
The left spring is a bearing, bearing by definition only, I realize this is actually a fit. I have made the bearing very rigid in the lateral directions, essentially cantilevering the rest of the shaft off of it.
Hopefully, the rest of it looks good. The first few mode shapes that the program computes are:
The table of computed critical speeds are:
Code:
******* Spin(1)/Whirl Ratio = 1.000 *******
no rpm R/S Hz
1 .173939E-01 .182148E-02 .289898E-03
2 6617.14 692.946 110.286
3 23774.2 2489.63 396.237
4 54967.9 5756.23 916.132
5 117665. 12321.9 1961.09
6 186694. 19550.6 3111.57
7 546068. 57184.2 9101.14
8 631345. 66114.3 10522.4
9 .159996E+07 167547. 26666.0
10 .244668E+07 256216. 40778.0
11 .281101E+07 294368. 46850.1
12 .492635E+07 515886. 82105.8
13 .685237E+07 717578. 114206.
14 .719070E+07 753008. 119845.
15 .334042E+08 .349808E+07 556737.
16 .504299E+08 .528100E+07 840498.http://www.eng.utoledo.edu/~mheminge/shaft_test.OU2 The file is open-able in wordpad, it lists the station properties, displacements, energy distributions, etc. Well, hopefully this helps, moreso, hopefully it matches what you tried to compute analytically. If there is any small changes in the inputs, then let me know and I'll try and find time to change it and rerun it.