Experimental stress analysis by strain gauging provides in-situ measurement of strain under real loading conditions and operation.  Strain gauging can supplement prior analysis (finite element) or stand alone in the determination of strains under critical loading.  The flexibility of the strain gauge method allows for recording during operation and helps in detecting unanticipated loading events.

The base portion of this propeller blade was strain gauged in a grid pattern to determine the influence coefficients for the geometry.  Once established, the location and magnitude of any applied load on the blade surface could be determined based on the output of the applied gauges.

A manufacturer was experiencing failure in a circuit board during the multi-step assembly of their product.  By mounting several miniature rosettes at locations of frequent solder breaks, the loads in the board were dynamically monitored at each assembly stage.  Through this monitoring, the step responsible for the failures was identified and corrective action was taken.

High pressure, hydrostatic burst testing was carried out on a section of large diameter linepipe.  The monitoring of the strains during the test included internally mounted strain gauges with high-pressure glands to allow the exit of the signal wires.  Strains in excess of 10,000 microstrain were recorded with rupture of the pipe occurring at an internal pressure of over 6,000 psi.  Upon completion of the tests, many of the gauges remained operational in spite of the high plastic strains experienced.

Zeus Engineering Ltd.
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