Common methods use strain gauges
and image correlation photogrammetry, while some other methods are available which measure the displacement and then calculate the strain.
Stress mechanism calibrated by strain gauge
, with base platform and monitor panel.
In the classical system of hole drilling method (blind hole) rosette type strain gauges
is used (ASTM E 837) that have a center mark locator for drilling (Fig.
where W--constant (W = 100 was assumed), [R.sub.1i]--measured value of resistance for deflection [X.sub.i] (where the number of measurements i = 1 to 100), [R.sub.10] - initial resistance of a strain gauge
(for deflection [X.sub.1] = 0 mm).
Stress measurements were carried out using 2 mm long, 120 [OMEGA] foil type strain gauges
, and an ac strain gauge
The basic issue of measuring with strain gauges
is to locate them properly on the structure.
When there is a change in strain gauge
resistance caused by a strain and the slightest amount of change is detected, the bridge circuit loses its symmetry and becomes unbalanced.
Therefore, a sensor with strain gauges
was designed for the purpose of biaxial force measurement.
Figure 4 presents comparison of torque versus time behavior derived from strain gauge
signals during calibration on TSHB apparatus.
Louis Statham, a physicist at the Curtiss-Wright Airplane Company, subsequently developed an unbonded strain gauge
and pioneered a transducer manufacturing company using this technology.
Moving a strain gauge
even slightly on the board may yield drastically different results.
Automation of the weight-changing mechanisms of these machines was accomplished about 1989, along with the implementation of instruments for the precise automated measurement of the responses of strain gauge
load cells used for measuring force.