dynamic effect of rotating / vibrating equipment

[alphaxy]

fellows,

I would like to ask if the propeller-like at the bottom of the equipment (attached in this thread) should be considered in designing the platform shown in the picture?

Do you have any guideline how to consider vibration in design?

Happy Holidays

Regards,
AlphaXY

 

[ishvaaag]

If it were by the Spanish code CTE, yes, in the sense of that there is a generic requirement of keeping all structural and non-structural elements reliably safe along the entire life of the construction, construction and demolition included.

Maximum forces exerted in 3 axes and perhaps a number of equivalent cycles may be the way to go, since it is that it is quite unlikely that having proper fasteners to a relatively thick reinforced concrete plate may exert damage elsewhere ... I mean, the reaction points themselves are the critical ones and where to fix your attention, the damage will happen there first.

 

[JoshPlumSE]

Most manufacturers of dynamic equipment will give you a "unbalanced" force for the operating speed of the equipment. This is based on imperfect balancing of the rotating (centrifugal) machinery.

You can also calculate this yourself from the following formula:

F = Rotor Weight * eccentricity of rotor weight* Machine Speed^2 / 12g

The reference I am pulling this from may be using a unit specific formula. So:
Rotor weight (kips)
eccentricity (inches)
Machine Speed (radians per second)
gravity = 32.2 ft / sec^2

 

[GregLocock]

You may also need to consider blade passing frequency, and its harmonics. f(Hz)=number of blades*rpm of shaft/60

Guessing from the photo, probably not a structural problem, may be a noise problem.

Cheers

Greg Locock

I rarely exceed 1.79 x 10^12 furlongs per fortnight

 

[Lion06]

When we are involved with adding equipment with dynamic characteristics to a floor and there are machines or equipment in the area that can be negatively impacted by the vibrating/rotating machine we will typically do a strength check of the structure using static loads provided by the manufacturer. This will typically include the maximum unbalanced loading as noted in an earlier post.

What we also do is provide a Revit model to a subconsultant of ours with the bay in question, and all adjacent bays. The model will typically included all slabs, beams, girders, columns, floor openings/penetrations, and anything else that is relevant to the dynamic properties of the floor system.

Other information we provide to the subconsultant are:
frequency of the rotating equipment
mass of what is being rotated/vibrated
the axis about which it's being rotated
the centroid of the rotating mass from the axis of rotation
the centroid of the rotating mass from the floor
the location of the rotating mass in plan
the locations (in plan) where sensitive equipment is located

With this information, our subconsultant meshes the structure, making a FE model and has software that will give the acceleration, peak velocity, and frequency at any point on the structure.

We use that information to compare to the criteria for the existing equipment that could be impacted by the new, vibrating/rotating machine.