Apparatus and method for measuring viscoelastic properties of materials
First Claim
1. Apparatus for measuring the viscous component and the elastic component of forces within a viscoelastic test specimen placed in shear, the test specimen being coupled to a platen having a rest position, the platen being displaceable from the rest position rotationally and axially relative to a fixed axis in response to rotational and axial forces exerted by the test specimen upon the platen as a result of said viscous component and said elastic component, the apparatus comprising:
- a first transducer coupled with the platen for applying a rotational counterforce to the platen for biasing the platen toward the rest position;
a first detector for detecting rotational movement of the platen away from the rest position;
first drive means for actuating the first transducer in response to the first detector to balance the rotational force exerted by the test specimen upon the platen with the rotational counterforce exerted by the first transducer upon the platen and maintain the platen at the rest position;
first indicating means for indicating the magnitude of the rotational counterforce;
a second transducer coupled with the platen for applying an axial counterforce to the platen for biasing the platen toward the rest position;
a second detector for detecting axial movement of the platen away from the rest position;
second drive means for actuating the second transducer in response to the second detector to balance the axial force exerted by the test specimen upon the platen with the axial counterforce exerted by the second transducer upon the platen and maintain the platen at the rest position; and
second indicating means for indicating the magnitude of the axial counterforce;
whereby the first indicating means provides a measure of the viscous component of forces within the test specimen and the second indicating means provides a measure of the elastic component of forces within the test specimen when the platen is at the rest position.
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Abstract
Apparatus and method for measuring the viscous component and the elastic component of forces within a viscoelastic test specimen placed in shear, the test specimen being coupled to a platen having a rest position, the platen being displaceable from the rest position rotationally and axially relative to a fixed axis in response to rotational and axial forces exerted by the test specimen upon the platen as a result of the viscous component and the elastic component, the apparatus and method including an arrangement of component parts and a plurality of steps for establishing a rotational counterforce for balancing the rotational force on the platen and simultaneously establishing an axial counterforce for balancing the axial force on the platen to maintain the platen at the rest position, and indicating the magnitude of the counterforces necessary to maintain the platen at the rest position, whereby the viscous component and the elastic component of forces are measured at zero compliance.
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Citations
23 Claims
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1. Apparatus for measuring the viscous component and the elastic component of forces within a viscoelastic test specimen placed in shear, the test specimen being coupled to a platen having a rest position, the platen being displaceable from the rest position rotationally and axially relative to a fixed axis in response to rotational and axial forces exerted by the test specimen upon the platen as a result of said viscous component and said elastic component, the apparatus comprising:
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a first transducer coupled with the platen for applying a rotational counterforce to the platen for biasing the platen toward the rest position; a first detector for detecting rotational movement of the platen away from the rest position; first drive means for actuating the first transducer in response to the first detector to balance the rotational force exerted by the test specimen upon the platen with the rotational counterforce exerted by the first transducer upon the platen and maintain the platen at the rest position; first indicating means for indicating the magnitude of the rotational counterforce; a second transducer coupled with the platen for applying an axial counterforce to the platen for biasing the platen toward the rest position; a second detector for detecting axial movement of the platen away from the rest position; second drive means for actuating the second transducer in response to the second detector to balance the axial force exerted by the test specimen upon the platen with the axial counterforce exerted by the second transducer upon the platen and maintain the platen at the rest position; and second indicating means for indicating the magnitude of the axial counterforce; whereby the first indicating means provides a measure of the viscous component of forces within the test specimen and the second indicating means provides a measure of the elastic component of forces within the test specimen when the platen is at the rest position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. The method of measuring the viscous component and the elastic component of forces within a viscoelastic test specimen placed in shear, the test specimen being coupled to a platen having a rest position, the platen being displaceable from the rest position rotationally and axially relative to a fixed axis in response to rotational and axial forces exerted by the test specimen upon the platen as a result of said viscous component and said elastic component, the method comprising the steps of:
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applying a rotational counterforce to the platen for biasing the platen toward the rest position; balancing the rotational force exerted by the test specimen upon the platen with the rotational counterforce applied to the platen to maintain the platen at the rest position; determining the magnitude of the rotational counterforce necessary to balance the rotational force; applying an axial counterforce to the platen for biasing the platen toward the rest position; balancing the axial force exerted by the test specimen upon the platen with the axial counterforce applied to the platen to maintain the platen at the rest position; and determining the magnitude of the axial counterforce necessary to balance the axial force; whereby the magnitude of the rotational counterforce provides a measure of the viscous component of forces within the test specimen and the magnitude of the axial counterforce provides a measure of the elastic component of forces within the test specimen when the platen is at the rest position. - View Dependent Claims (23)
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Specification