HANNOVER MESSE 2018, 23 - 27 April

Smart Bolts

Measurement of pre-tensioning forces in screw connections

CiS Forschungsinstitut für Mikrosensorik

Exhibitor details
Logo Smart Bolts

Exhibition stand
Topic: German Pavilion - Thuringia

Product description

CiS Research Institute is currently developing a new silicon-based MEMS sensor to verify safety-related screw connections. Such special screws are used in mechanical engineering, conveyor technology and wind turbines, e.g.
The new sensor is applied to the screw head and measures its deformation caused by the screw pre-tensioning force. Not to be confused with the torque, the screw pre-tensioning force affects the parts to be connected between the thread and the screw head. It causes an elastic deformation in all parts of the screw. At the screw head, this deformation is quite easy to measure. Up to now the strain on the screw could only be determined by measuring its length or attaching strain gauges at the screw shaft. These solutions lend themselves specifically to the evaluation of single screws. The MEMS sensor developed by CiS Research Institute consists of four piezo-resistive, strain-sensitive measurement resistors which are switched to a Wheatstone bridge. The active surface without the electrical connections amounts to no more than (200 x 200) µm² with a thickness of 10 µm (fig. 1). The sensor is joined to the screw head using glass solder. A FEM-analysis determined the most suitable position on the screw head (fig. 2).

Development status
Under development

Market introduction

Degree of documentation
Very well documented

Market orientation
Niche market

All products offered by this exhibitor


Advanced UV for Life

Flexible and efficient assembly of UV-LEDsread more


Barometric MEMS pressure sensor

Plasma etching technology opens up new geometries for MEMS sensorsread more


Smart Bolts

Measurement of pre-tensioning forces in screw connectionsread more


Fast and small spectral sensors for FBG

With stacked silicon photodiodes and refined optical thin film filters, spectrally sensitive detectors can be developed that can replace conventional, expensive spectrometers needed for special applications. A further feature of such spectral sensors is the elimination of measurement errors caused by more


Multi Lambda UV LED

Stable UV LED Moduleread more


RISEQ Light Sensor

Detecting the Direction of Incident Lightread more

Stored items


Server communication error: Item could not be saved.