Question

I would like to test my hardware under vibration that can appear on a highway gantry. If someone has a model of such vibration. i.e period and amplitude.

In my lab I have a motor that can be regulated according to its RPM.

Answer 1

Vibration testing is often done using a couple methods:

Random vibration according to a specified power spectral density envelope.
Sinusoidal vibration ramps across a specified spectral envelope (simpler than the above, but takes longer due to ramp time, usually 1/2 an octave per minute)

Related, but usually separated is shock (e.g. drop) testing, which is done with the device packed (for shipping) and unpacked (installation mishaps). Each of the tests is applied to the device along the three axes while the device is powered and operating.

The idea is that because the tests cover all frequencies (in the specified range) along three orthogonal axes, so any vibration in practice will just be some combination of the test spectrum (in frequency and direction).

Devices are usually most sensitive to frequencies where there is some sort of resonance. In electronics (my field), a common problem is electrolytic capacitors that can be literally ripped off the board via shaking at their resonant frequency. The easy solution is to 'goop' them down with some RTV silicone, which doesn't really hold them in place as much as it damps the vibration so they don't get as excited.