How to Get the Most out of the Technical Features

Force Application with Compressive Force Sensors

Special features of force sensors with an internal bore and compression bars

Force sensors with an internal bore and compression bars such as the C6B from HBM offer numerous advantages:

• A very high stiffness and a high fundamental frequency – the ideal choice for dynamic measurement tasks
• A robust design that ensures immunity to corrosive influences as well as vibration or shock
• A cost-effective solution
• Availability for extremely high capacities (HBM products up to 10 MN)

Since these compressive force transducer types do not have convex load application parts, mechanical connection them is easy.

Uniform force application

The high stiffness and the absence of a central force application part require reasonable care to be taken to ensure proper sensor mounting. The strain gauges that convert the applied force into a measurable change in resistance are installed at four different points over the circumference of the transducer. The force must be applied uniformly to the circumference to attain good results and to be converted into strain as uniformly as possible. Unevenness and tilting are not compensated for by those sensors because they have very small displacements.

HBM offers loading fittings for the C6B compressive force transducer that meet the above-mentioned requirement, i.e. they ensure a uniform mechanical stress distribution. In general, compact force sensors with an internal bore and compression bars are, however, slightly more likely to be affected by the mounting conditions. Therefore, load application parts are provided that can be ordered alongside the C6B to address this issue. The special feature: The sensor and the load application parts that will be used in the application will be calibrated together. The parts are marked accordingly at HBM to ensure that it is always only the combination calibrated by HBM that is used for taking a measurement. Both spherical caps (see fig. below) and load buttons can be used, which, in turn, ensure a convex load application; matching thrust pieces are available.

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