Hi,
Currently im working on vibration analysis for a pump equipment support.
Following is the step i did.
Step 1,
Modelling of beam supporting the pump with discrete joint where the interface bolt is attached to the structure. These interface bolt is set with retain degree of freedom (222000) point of interest only andthe whole topside hard point is not having any retained degree of freedom. No dummy modeling of pump with CoG is included.
Step 2
Run free vibration analysis to generate the mass and mode file.
Step 3
Create dynamic input file using engine vibration analysis which is available in dynamic reponse module.
Step 4
Define the min & max operating RPM. Interpolation power of 2 is used. User defined RPM to be analyzed by SACS.
Step5
Define the unbalance dynamic load in X, Y, & Z Direction at the interface bolt joint with no phase angle being input. All translation dynamic load is group in the same group load case. Define with non-linear interpolation to be used by SACS.
Step 6
Run engine vibration.
Used file is mass, mode and the engine dynamic input file.
Question.
1. In step 5, how SACS use the information. Will it be applied as per user input direction translation or rotation in combination for defined RSPEED and generate the respone base on it together with the dynamic mode natural frequency close to the defined RSPEED?
2. Is it accurate to read the interface bolt response using this module or time history analysis?
3. There is option card "Mode select" to select particular mode from free vibration analysis. If i use this option card and define the structural mode that it is close to operating RPM of equipment it is the correct way to represent the interface bolt response for a single operating RPM of a pump and ignore the modes from the free vibration analysis?