Strain measurement method and device
AssigneeKabushiki Kaisha
InventorKoichi Kobayashi
Life of this patent
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Abstract
A non-contacting strain measurement method and system employs a laser light source for irradiating a test piece to provide a spectral pattern in spaced relationship from the test piece. The pattern is viewed while the test piece is placed under tension by a plurality of video cameras. The CCD video cameras are coupled to signal processing circuits which calculate the Poisson ratio according to the formula: εxx=−ΔAx/2L0 tan θ0
Claims20
A strain measurement method for a test piece for determining the Poisson's ratio comprising the steps of:
- irradiating the surface of a test piece with a laser beam for generating a spectral pattern;
- and
- viewing the changes in the spectral pattern as the test piece is placed under a tensile force.
A strain measurement system for measuring the Poisson's ratio of a test piece without physically contacting the test piece comprising:
- a laser light source for directing a beam of energy onto a surface of a test piece for generating a spectral pattern;
- and
- at least one video camera for viewing the changes in said spectral pattern as a tensile force is applied to said test piece.
A strain measurement system for measuring the Poisson's ratio of a test piece without physically contacting the test piece comprising:
- a laser light source positioned to direct a laser beam onto a surface of a test piece for generating a spectral pattern in spaced relationship to said test piece;
- at least one video camera for viewing the changes in said spectral pattern as a tensile force is applied to said test piece;
- and
- signal processing circuits coupled to said video camera for calculating the Poisson ratio based upon changes in said spectral pattern as tension is applied to said test piece.
Dependencies are inferred from the claim text.