Testing of samples
AssigneeInstron Corporation
InventorsPaul D. Hayford, David W. Long
Life of this patent
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Abstract
A method of monitoring the surface of a sample under test is provided and the method comprises the steps of: illuminating the surface with light (20) polarised in a first direction; viewing light reflected from the surface through a polarising filter (27) arranged at 90° to the first direction, wherein the surface of the sample under test is provided with a marked area where diffuse reflection of the incident polarised light will occur in order to improve the contrast between the marked area and the surface of the sample under text.
Claims8
A method of monitoring strain within a sample under test comprising the steps of:
- preparing a sample with a reflective surface;
- illuminating the surface with light polarised in a first direction by a first polarising filter while strain in the sample is altered;
- viewing light reflected from the surface through a second polarising filter arranged at 90° to the first direction,
- wherein the surface of the sample under test is provided with multiple marked areas where diffuse reflection of the incident polarised light will occur in order to improve the contrast between the marked areas and the surface of the sample under test, and wherein change in position of the marked areas with respect to one another is monitored to determine a strain in the sample.
A system for monitoring the strain within a sample comprising:
- a sample with a reflective surface having multiple marked areas;
- means for holding the sample;
- means for altering the strain in the sample;
- means for illuminating the surface with light;
- a first polarising filter positioned between the sample and the means for illuminating the surface with light, for polarising the light in a first direction;
- an optical arrangement for monitoring the change in position of the marked areas with respect to one another on the surface of the sample to determine strain in the sample;
- and
- a second polarising filter disposed in front of the optical arrangement and oriented such that its direction of polarisation is 90° to the first direction, wherein the marked areas cause diffused reflection of incident polarised light in order to improve the contrast between the marked area and the surface of the sample.
Dependencies are inferred from the claim text.