ansys结果后处理(画出campbell图)

nokian7210

模态分析计算出来后，怎样在后处理中画出campbell图，望各位给予帮助！！

gy9991

就是啊，连这个也没人知道吗？大家都是高哪一方面研究的啊！

ChaChing

ansys没用过, 完全外行!
但模态分析的结果, 足够画出campbell图吗? 待高人路过

16443

campbell图是转速和频率的关系，ansys的模态分析是一种静态的模态分析，不能得出campbell图的。
用谐响应分析试试，可以输入转速的谐载荷激励，不过我没做过这个。

orangecici

在模态分析结束后，用PLCAMP, Option, SLOPE, UNIT, FREQB, Cname, STABVAL这个命令，可以看到CAMPBELL图，要在ansys11.0中。

16443

PLCAMP, Option, SLOPE, UNIT, FREQB, Cname, STABVAL

Plots Campbell diagram data for applications involving rotating structure dynamics.

POST1: Special Purpose

MP ME ST PR PRN <> <> <> <> <> <> PP <>
Option
Flag to activate or deactivate sorting of forward or backward whirl frequencies:

0 (OFF or NO) -- No sorting.  
1 (ON or YES) -- Sort. This value is the default.

SLOPE
The slope of the line to be plotted. This value must be greater than 0. The line represents the number of excitations per revolution of the rotor. For example, SLOPE = 1 represents one excitation per revolution, usually resulting from unbalance. The default is no line.

UNIT
Specifies the unit of measurement for rotational angular velocities:

RDS -- Rotational angular velocities in radians per second (rad/s). This value is the default.
RPM -- Rotational angular velocities in revolutions per minute (RPMs).

FREQB
The beginning, or lower end, of the frequency range of interest. The default is zero.

Cname
The rotating component name.

STABVAL
Flag to plot the stability values:

0 (OFF or NO) -- Plot the frequencies (the imaginary parts of the eigenvalues in Hz). This value is the default.  
1 (ON or YES) -- Plot the stability values (the real parts of the eigenvalues in Hz).
2 -- Plot the logarithmic decrements.

For more information about complex eigenvalues and corresponding logarithmic decrements, see Damped Method in the Theory Reference for ANSYS and ANSYS Workbench.

Notes
To take the gyroscopic effect into account when plotting a Campbell diagram, first issue the CORIOLIS command in the SOLUTION module.

The PLCAMP command is valid only for modal analyses (QR damped [MODOPT,QRDAMP] or damped [MODOPT,DAMP] methods only). The command works over two or more load step results generated with an ascending order of rotational velocity (OMEGA or CMOMEGA).

Complex eigenvalues are necessary (MODOPT,QRDAMP,,,,Cpxmod = ON), and you must specify the number of modes to expand (MXPAND) at each load step.

In some cases where modes are not in the same order from one load step to the other, sorting (Option = 1) the frequencies can help to obtain a correct plot. Sorting is based on the comparison between complex mode shapes calculated at two successive load steps.

At each load step, ANSYS compares the mode shape to the loads at other loads steps to determine whirl direction at the load step. If applicable, a label appears (in the plot legend) representing each whirl mode (BW for backward whirl and FW for forward whirl).

ANSYS considers the SLOPE value only if the frequencies are plotted (STABVAL = OFF).

At each load step, ANSYS checks for instability (based on the sign of the real part of the eigenvalue). The labels “stable” or “unstable” appear in the plot legend for each frequency curve.

The rotational velocities of a named component (Cname) are displayed on the X-axis.

To plot the Campbell diagram for a prestressed structure, first issue a CAMPBELL,ON command in the static portion of the analysis.

In general, ANSYS, recommends plotting a Campbell diagram only when your analysis is performed in a stationary reference frame (CORIOLIS,,,,RefFrame = ON).

For a usage example of the PLCAMP command, see Sample Campbell Diagram Analysis.

16443

例子：
The model is a simply supported beam spinning at up to 30,000 rd/s.

1. 
   
2. /title, Spinning simply supported beam
   
3. !* Parameters
   
4. lx=8 ! length
   
5. dia=0.2 ! diameter
   
6. !*
   
7. /PREP7
   
8. ET,1,16
   
9. R,1, dia, dia/2
   
10. MP,EX,1,2e+11
    
11. MP,DENS,1,7800
    
12. MP,PRXY,1,0.3
    
13. n,1
    
14. n,9,lx
    
15. fill,1,9
    
16. e,1,2
    
17. egen,8,1,-1
    
18. d,1,uy,,, ,,uz      ! simply supported left end
    
19. d,9,uy,,, ,,uz      ! simply supported right end
    
20. d,all,ux            ! supress axial motion
    
21. d,all,rotx          ! supress torsion
    
22. finish
    
23. !*
    
24. /SOLU
    
25. antype,modal
    
26. !
    
27. ! Use the QRDAMP eigensolver, request 8 modes,
    
28. !   and specify complex eigensolutions
    
29. modopt,qrdamp,8,,,on
    
30. !
    
31. ! Apply Coriolis effect and specify
    
32. !   stationary reference frame
    
33. coriolis,on,,,on
    
34. !
    
35. omega,0.
    
36. mxpand,8
    
37. solve
    
38. omega,30000.
    
39. mxpand,8
    
40. solve
    
41. finish
    
42. !*
    
43. /POST1
    
44. ! Plot Campbell Diagram
    
45. plcamp,on
    
46. finish
    

复制代码

皮卡丘

16443 发表于 2009-7-7 12:23

                               
登录/注册后可看大图

例子：
The model is a simply supported beam spinning at up to 30,000 rd/s.

高手啊  学习了

cluochong

ANSYS坎贝尔图分析注意事项
Posted on 2011/11/11
如果使用PLCAMP命令画出旋转结构的坎贝尔图，则有以下要求和注意事项：

1.在静止参考系下分析(Static reference frame)
2.结构必须是轴对称的 (Axial-symmetry)
3.如果要包括科氏力的作用，必须在SOLUTION模块中先运行CORIOLIS命令
4.首先分析固有频率
5.分析固有频率只能使用MODOPT, QRDAMP或者MODOPT, DAMP方法
6.需要在多个载荷步上分析固有频率，指定不同的转速，且转速应该随载荷步递增。OMEGA, CMOMEGA
7.需要求解复特征值(MDOPT, QRDAMP,,,,Cpxmod=ON)，而且必须在各载荷步上指定要扩展的模态数目(MXPAND)。
8.某些情况下，模态和载荷步的顺序不一致，可以使用PLCAMP sorting option =1对频率排序。排序原则是基于两个连续载荷步上计算的复模态振型。
9.在每个载荷步上，ANSYS比较模态振型
第二条怎么解释啊？各位大神，求帮助

walst

现在Workbench14也可以做坎贝尔图了！