### Sherlock Damping Factors

Posted:

**28 Mar 2014, 11:31**Sherlock uses mode based damping computed from the natural frequencies. The damping factor field supplied in the analysis properties (random, harmonic) is a modifier for the computed mode based damping factors.

If you want to look at the computed damping factors for comparison factors you need to look at the generated .inp file for the analysis located in the project folder. For example:

C:\Users\nblattau\AppData\Roaming\Sherlock\projects\ODB++ Tutorial\ODB++ Tutorial\modules\HarmonicVibe\calculix-HV.inp

Open the file with notepad (or a better text editor), scroll to the end and you will see the computed damping factors:

** End of Model

**-------------------------------------------------------

**-------------------------------------------------------

** HARMONIC VIBRATION ANALYSIS STEP

**-------------------------------------------------------

*Step

*Steady State Dynamics

1.0E01,1.0E03,5,3

**

*MODAL DAMPING

1,1,7.3452E-03

2,2,1.4526E-02

3,3,2.1379E-02

4,4,2.5118E-02

5,5,3.1541E-02

6,6,3.6158E-02

7,7,4.0499E-02

8,8,4.3865E-02

9,9,4.7411E-02

**

*Amplitude, name=HarmonicAmpl

1.0E01, 1.0E00

1.0E03, 1.0E00

**

*DLOAD, AMPLITUDE=HarmonicAmpl, OP=NEW

ALL_ELEMENTS,GRAV,9.8066E03,0.0E00,0.0E00,-1.0E00

**

*node file, frequency=1, output=3D

PU

*el file

E

*endstep

You can increase or decrease the damping with the Sherlock damping factor property. Numbers below one reduce the damping (a straight multiplier), 0.1 multiplies all the computed damping factors by 0.1.

If you want to look at the computed damping factors for comparison factors you need to look at the generated .inp file for the analysis located in the project folder. For example:

C:\Users\nblattau\AppData\Roaming\Sherlock\projects\ODB++ Tutorial\ODB++ Tutorial\modules\HarmonicVibe\calculix-HV.inp

Open the file with notepad (or a better text editor), scroll to the end and you will see the computed damping factors:

** End of Model

**-------------------------------------------------------

**-------------------------------------------------------

** HARMONIC VIBRATION ANALYSIS STEP

**-------------------------------------------------------

*Step

*Steady State Dynamics

1.0E01,1.0E03,5,3

**

*MODAL DAMPING

1,1,7.3452E-03

2,2,1.4526E-02

3,3,2.1379E-02

4,4,2.5118E-02

5,5,3.1541E-02

6,6,3.6158E-02

7,7,4.0499E-02

8,8,4.3865E-02

9,9,4.7411E-02

**

*Amplitude, name=HarmonicAmpl

1.0E01, 1.0E00

1.0E03, 1.0E00

**

*DLOAD, AMPLITUDE=HarmonicAmpl, OP=NEW

ALL_ELEMENTS,GRAV,9.8066E03,0.0E00,0.0E00,-1.0E00

**

*node file, frequency=1, output=3D

PU

*el file

E

*endstep

You can increase or decrease the damping with the Sherlock damping factor property. Numbers below one reduce the damping (a straight multiplier), 0.1 multiplies all the computed damping factors by 0.1.