Method for continuous determination of the elastic stiffness of contact between two bodies
OwnerWarren C. Oliver, John B. Pethicainventors
Life of this patent
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Abstract
A method for continuously measuring the stiffness and area of contact between two bodies is provided. Elastic stiffness of a junction is measured by introducing a relatively small oscillatory mechanical force at a known frequency to the junction and measuring the subsequent displacement response using AC signal-handling techniques to provide a continuous measurement proportional to the stiffness and the area of contact between the bodies, even as the area of contact changes.
Claims15
A method for continuously measuring the stiffness of contact between first and second bodies, comprising the steps of:
- applying an oscillating mechanical excitation at an arbitrary selected fixed frequency and a known amplitude to the contact junction of said first and second bodies;
- and, simultaneously applying a load independently of said fixed frequency to the contact junction;
- measuring the resulting mechanical response between said first and second bodies relative to the applied oscillatory excitation at said load as an indication of the stiffness of contact between said first and second bodies.
A method for continuously measuring the stiffness of contact between first and second bodies, comprising the steps of:
- applying an oscillating mechanical force (F) at an arbitrary selected fixed frequency and a known amplitude to the contact junction of said first and second bodies;
- and, simultaneously applying a load independently of said fixed frequency to the contact junction;
- measuring the resulting oscillatory displacement response between said first and second bodies relative to the applied oscillatory force at said load as an indication of the stiffness of contact between said first and second bodies.
A method for continuously measuring the stiffness of contact between an indenter probe and a sample being tested in an indentation testing system including a computer for controlling the application of a direct mechanical force to the junction between said probe and said sample and monitoring the displacement of said probe so as to determine mechanical properties of said sample as said direct mechanical force is applied in accordance with a selected loading and subsequent unloading cycle of said junction, comprising the steps of:
- applying an oscillatory mechanical force to said junction superimposed on said direct mechanical force of sufficient frequency and amplitude to continuously load and unload said junction, and simultaneously
- measuring the resulting oscillatory displacement response of said probe relative to the applied oscillatory mechanical force as an indication of the stiffness of contact between said probe and said sample.
Dependencies are inferred from the claim text.