I have a system of recriprocating compressor. I need to achive a frequency of 7hz.what are the procedures to be followed while doing modal analysis. please check the modal analysis correct or not.

what is the use of the option: Additional mass points desired for dynamic analysis, in massspace.exe.

1.WHAT IS THE DIFFERENCE BETWEEN "MODE MASS NORMALIZED" AND "MODE MASS UNITY"
2.IN THE FIRST 1.JPG ATTACHMENT. WHAT HAS TO BE THE INPUT IN "LUMPED MASSESS"

3. HOW TO MODEL A SNUBBER AND WHAT HAS TO BE MENTIONED IN THE "2.JPG" FILE "SNUBBER COLUMN" WHILE DOING MODAL ANALYSIS

1. Mass normalized mode shapes include the portion of mass associated with each mode while unity normalized do not. Most users refer to the unity normalized mode shapes since that gives a better indication of shape since, in every case, the maximum value is 1.0.
2. The Lumped Mass tab allows you to add additional mass that has not (for some reason) been included in the static model or otherwise adjust the mass model used in the dynamic analysis. With no added input here, the program will use the static model input to determine the mass distribution.
3. Snubbers (in CAESAR II) are modeled as (very stiff) springs that can be turned on or off on individual static load cases ("on" for quick acting loads and "off" for non-quick-acting loads) and are active for all dynamic analyses. They can be defined in the original (static) model or here in the dynamic input.