Displacement and deformation monitoring method and system without using any strain sensor, and components thereof

Patent metadata

Field	Value
Publication number	US-10641664-B2
Application number	US-201916262305-A
Country	US
Kind code	B2
Filing date	Jan 30, 2019
Priority date	Apr 21, 2017
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A monitoring method and system include an antenna disposed spaced from a structural member (SM), which itself can be the target object or attachable to a target object, without using any in-dwelling strain sensor. The antenna is arranged to not touch the SM in at least the no load condition. As the target object undergoes displacement and/or deformation, the SM undergoes displacement and/or deformation. The SM is juxtaposed, partially contained with, or fully contained within a magnetic or electromagnetic field and electromagnetically coupled to the emitting antenna. Characteristics of the electromagnetic field coupling between the antenna and the SM shift over time due to the displacement and/or deformation applied to the SM. The shift in the characteristics of the electromagnetic field coupling between the antenna and the SM over time can be used to determine the temporal change in deformation and/or displacement of the SM over time to enable diagnosis of the target structural object being monitored.

First claim

What is claimed is:

1. A method of monitoring changes in a structural member (SM) as the SM undergoes at least one of displacement or deformation, the method comprising:
a disposing step of disposing an antenna spaced from the SM so that a portion of the antenna confronting the SM does not contact the SM at least at no load condition;
an inducing step of inducing a magnetic or electromagnetic field in the vicinity of the SM to create a coupling of the magnetic or electromagnetic field between the antenna and the SM, where characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM are associated with one of the distance between the SM and the emitting antenna or the deformation state of the SM;
an outputting step of outputting electrical signals representing the characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM, without using any strain sensing device directly attached to the SM;
a first determining step of determining the characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM based on the electrical signals; and
a storing step of storing the determined characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM in a storage device.

2. The method according to claim 1 , further comprising:
a repeating step of repeating the inducing step, the outputting step, the first determining step, and the storing step at a predetermined interval for one of an evaluation period or until a predetermined number of the characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM has been determined.

3. The method according to claim 2 , further comprising:
a second determining step of determining a shift in characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM over the evaluation period or a time lapsed to determine the predetermined number of the characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM.

4. The method according to claim 3 , further comprising:
a third determining step of determining a temporal change in relative displacement or deformation of the SM over the evaluation period or the time lapsed based on the shift determined in the second determining step.

5. The method according to claim 1 , wherein the SM is mountable to a target object to be monitored, the SM undergoing the at least one of displacement or deformation as the target structural object undergoes at least one of displacement or deformation.

6. The method according to claim 1 , further comprising:
a loading step of applying a known or measurable force or moment to the SM; and
an analyzing step of analyzing the determined characteristics in relation to the known or measurable force of moment applied to the SM in the loading step.

7. The method according to claim 5 , further comprising:
a loading step of applying a known or measurable force or moment to the SM; and
an analyzing step of analyzing the determined characteristics in relation to the known or measurable force of moment applied to the SM in the loading step.

8. The method according to claim 1 , wherein:
the inducing step comprises using the antenna that has at least one wire configured to induce the magnetic or electromagnetic field and output the electrical signals, which is readable by a network analyzer, and
the at least one wire is connectable to an input port of the network analyzer.

9. The method according to claim 8 , wherein the at least one wire comprises a coaxial cable.

10. The method according to claim 1 , wherein:
the inducing step comprises using the antenna that has a first wire configured to induce the magnetic or electromagnetic field; and
the outputting step comprises using the antenna that further has a second wire configured to output the electrical signals, which is readable by a network analyzer, and
the first and second wires are connectable respectively to first and second input ports of the network analyzer.

11. The method according to claim 9 , wherein each of the first and second wires comprises a coaxial cable.

12. The method according to claim 4 , wherein the change in relative displacement or deformation of the SM over the evaluation period or the lapsed time is represented as a slope of resonant frequency/load.

13. The method according to claim 12 , wherein a degree of the slope represents stability, with a higher slope representing a more unstable condition and a less slope representing a more stable condition.

14. A system for monitoring changes in a structural member (SM) as the SM undergoes one of displacement or deformation, the system comprising:
an antenna configured to:
induce, using a first electrical signal, a magnetic or electromagnetic field in the vicinity of the SM to create a coupling of the magnetic or electromagnetic field between the antenna and the SM, where characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM are associated with one of the distance between the SM and the emitting antenna or the deformation state of the SM; and
output a second electrical signal representing the magnetic or electromagnetic field coupling between the antenna and the SM, without using any strain sensing device directly attached to the SM;

an antenna holder configured to hold the antenna at a fixed distance spaced from the SM so that a portion of the antenna confronting the SM does not contact the SM at least at no load condition;
a network analyzer configured to:
output the first electrical signal to the antenna for inducing the magnetic or electromagnetic field;
receive the second electrical signal from the antenna; and
determine the characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM based on the received second electrical signal;

a controller including a memory storing instructions and a processor configured to implement instructions stored in the memory and execute:
a collecting task that stores, in the memory or another storage device, a plurality of characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM determined at a predetermined interval by the network analyzer over an evaluation period;
a first determining task that determines a shift in characteristics of the magnetic or electromagnetic field coupling between the antenna and the SM over the evaluation period; and
a second determining task that determines a temporal change in relative deformation or displacement of the SM over the evaluation period.

15. The system according to claim 14 , wherein:
the antenna comprises at least one wire configured to receive the first signal to induce the magnetic or electromagnetic field, and output the second signal, and
the at least one wire is connectable to at least one input port of the network analyzer.

16. The system according to claim 14 , wherein:
the antenna comprises a first wire configured to receive the first signal to induce the magnetic or electromagnetic field and a second wire configured to output the second electrical signal, and
the first and second wires are connectable respectively to first and second input ports of the network analyzer.

17. The system according to claim 15 , wherein the at least one wire comprises a coaxial cable.

18. The system according to claim 16 , wherein each of the first and second wires comprises a coaxial cable.

Assignees

• Univ Colorado State Res Found

Inventors

• Puttlitz Christian M
• Demir Hilmi Volkan
• Labus Kevin M
• Mcgilvray Kirk C
• Unal Emre

Classifications

• G01M5/0041

  by determining deflection or stress · CPC title

• A61B2562/0261

  Strain gauges · CPC title

• G01N3/00

  Investigating strength properties of solid materials by application of mechanical stress · CPC title

• A61B5/05

  Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves (measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24) · CPC title

• G01N3/066

  with electrical indicating or recording means · CPC title