Multifunctional piezoelectric load sensor assembly

Patent metadata

Field	Value
Publication number	US-10620063-B2
Application number	US-201615747691-A
Country	US
Kind code	B2
Filing date	May 31, 2016
Priority date	Jul 31, 2015
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

A piezoelectric sensor assembly for measuring a force quantity on a structure includes at least one piezoelectric sensor, each including an element and two electrodes each projecting outward from the element. An electronic processor of the assembly is configured to receive data from the sensor, wherein the data includes a voltage with a magnitude that is indicative of a dynamic load (i.e., amplitude modulation mode) placed upon the structure. The processor may be configured to interrogate the piezoelectric sensor for its resonant frequency change which is indicative of the load applied to the structure at low operation frequency and to which the piezoelectric sensor would not otherwise respond well. The dual mode operation of the piezoelectric sensor extends the frequency range of the strain measurement from the dynamic range to static or quasi-static range.

First claim

What is claimed is:

1. A joint, comprising:
one or more bolts or rivets connecting one or more parts of a structure;
a piezoelectric sensor assembly for measuring a force quantity on the structure for load path monitoring and damage detection, the piezoelectric sensor assembly comprising:
at least one piezoelectric sensor, each including an element and two electrodes each projecting outward from the element; and
an electronic processor configured to receive data from the electrodes, wherein the electronic process includes a static sensing mode for measuring a static load and a dynamic sensing mode for measuring a dynamic load, wherein the data includes a voltage indicative of a load placed upon the structure, and wherein the processor is configured to process the data into a force quantity value based on a first LRC circuit model in the static sensing mode when a frequency of the load is within a first frequency range and a second LRC circuit model when the frequency of the load is within a second frequency range in the dynamic sensing mode.

2. The joint set forth in claim 1 , wherein a tuned and unloaded resonant frequency, and a measured and loaded resonant frequency is associated with a combination of the sensor and the structure, and a difference between the tuned resonant frequency and the measured resonant frequency is directly proportional to the force quantity value.

3. The joint set forth in claim 1 , wherein the data includes a measured resonant frequency associated with a combination of the sensor and structure that varies with the load.

4. The joint set forth in claim 1 , wherein the load includes a static load having a load frequency of about less than 3 Hz.

5. The joint set forth in claim 1 , wherein the processor in the dynamic sensing mode measures the dynamic load having frequency that is greater than about 3 Hz.

6. The joint set forth in claim 1 , wherein the piezoelectric sensor assembly is configured to measure the force quantity in a broad load frequency range including a low frequency range associated with the force quantity measured via frequency modulation utilizing the first LRC circuit model, and a high frequency range associated with the force quantity measured via magnitude-based load monitoring utilizing the second LRC circuit model.

7. A method of load path monitoring and damage detection in a joint structure, the method comprising:
operating a piezoelectric sensor element for measuring load in the joint structure;
processing data received from a sensor element by a processor in a static sensing mode using a first LRC circuit model for loads having a low frequency range; and
processing data received from the sensor element by the processor in a dynamic sensing mode using a second LRC circuit model for loads having a high frequency range.

8. The method set forth in claim 7 , wherein the static sensing mode compares changes in resonant frequency of a combination of the sensor element and the structure.

9. The method set forth in claim 7 , wherein the low frequency range is from about zero to about 3 Hz, and the high frequency range is greater than about 3 Hz.

10. The method set forth in claim 7 , further comprising:
establishing a baseline resonant frequency associated with a combination of the sensor element and structure without load.

11. The method set forth in claim 10 comprising:
measuring a resonant frequency associated with the combination of the sensor element and structure when loaded; and
comparing the measured resonant frequency to the baseline resonant frequency.

12. The method set forth in claim 11 , wherein the changes in resonant frequency are proportional to the load.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Sun Fanping
• Chaudhry Zaffir A
• Sarlashkar Jr Avinash

Classifications

• G01L1/162 Primary

  using piezoelectric resonators · CPC title

• G01M5/0083

  by measuring variation of impedance, e.g. resistance, capacitance, induction · CPC title

• G01M5/0033

  by determining damage, crack or wear · CPC title

• G01H11/08

  using piezoelectric devices · CPC title

• H01L41/1132

  Electricity · mapped topic