Mounting/installing an accelerometer

How to mount an accelerometer to the unit under test?

When mounting an accelerometer to a test structure, the most important consideration is to have a quality mounting surface to attach it. The primary goal is to achieve a maximum useable frequency response for performing a vibration measurement. Since the mounting surface conditions affect transmissibility, a variety of adhesive mounting pads, clips, magnetic bases, studs and triaxial cubes with accurately prepared mounting surfaces are available for use in a wide range of applications. When frequencies higher than two to three kHz are considered, each accelerometer instruction manual provides specific recommendations for surface quality, sensor orientation and mounting torque. 

Which are the methods to mount an accelerometer to a unit under test?

There are numerous methods to install an accelerometer. Depending on properties of the test unit, environmental conditions and application, the sensor can be mounted on a magnetic base, by means of adhesive pads, adhesive wax, adhesive cement or (isolated) mounting studs.

Which advantages or disadvantages do the various methods to install an accelerometer have?

Mounting methodAdvantagesDisadvantagesRemarks
ProbeQuick measurementLower accuracy
Magnetic baseEasy and quick installationAdds considerably to mass loading, lowers resonant frequencyLimited to ferromagnetic materials
Adhesive mounting baseAllows for stud mounting, provides electrical isolationLowers resonant frequencyPads are usually exposed to test specimen
Adhesive waxIdeal for lightweight unitsLimited temperature range and acceleration amplitudeFast and clean
Adhesive cementGood and strong coupling of sensor to specimen; higher temperature stability than waxDifficult to remove sensor; requires solvents, removal tool and/or heatSuited for more permanent applications and high frequency measurements
Isolated mounting studAllows for strong coupling as well as for ground isolationRequires threaded hole in specimen; base slightly lower resonance frequencyControl mounting torque; use silicone grease
Mounting studBest coupling of sensor to test specimen for highest frequency responseRequires threaded hole in specimenControl mounting torque; use silicone grease