Cylindrical Gauges (LB11/TB21)

LB11 & TB21: Strain Gauges for Measurements in Screws and Bolts

Bolts are a common construction element used to connect various components. The LB11 and TB21 series of cylindric strain gauges with lead wires, have especially been designed to measure strain, force, and vibration in bolts, screws, and other axial construction elements. 

They have been equipped with copper leads and can be used directly in pre-drilled bolt elements. For this, a 2 mm drilling in the structure is required. Both, LB11 and TB21, come as a tubular strain gauge that can be used in a temperature range of –200°C to +140°C.

• The LB11 has a linear measuring grid in the strain direction. It is suitable for quarter-bridge applications and has a resistance of 120 Ω.                                     
• The TB21 has two measuring grids arranged at 90° and is connected as a half-bridge. This allows for an improved temperature compensation at varying temperatures. The temperature compensation at +-5 °K temperature change causes a drift in the range of 0 to 80 µm/m, depending on the screw and the installation. This is due to the geometry of the application and differs significantly from installations on planar objects. The resistance of the strain gauge is 1000 Ω (+/- 1%).