Structural Health Monitoring Systems And Methods

• US 20130204592A1
• Filed: 04/05/2011
• Published: 08/08/2013
• Est. Priority Date: 04/05/2010
• Status: Abandoned Application

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Dixit, Akash, Hanagud, Sathya, Hodges, Dewey
• Application Number:
  US13/639,796
• Publication Number:
  US 20130204592A1
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G01M 5/0025 of elongated objects, e.g. pipes, masts, towers or railways G01M5/0058 takes precedence
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]

Abstract

Systems and methods of discovering damages in structures, systems and methods of modeling how a structure will behave once damage has been discovered, and a structure that does not change it natural frequency if there is loss or addition of mass or stiffness in the structure.

Claims

1. A process of modeling an element with a discontinuity to obtain one or more vibrational characteristics of the element with the discontinuity, the process comprising:

providing the physical characteristics of the element;

providing one or more vibrational characteristics of the element without the discontinuity;

perturbing one or more vibrational characteristics of the element without the discontinuity based on characteristics of the discontinuity;

calculating nth-order, perturbed differential equations governing one or more vibrational characteristics of the element with the discontinuity, wherein n is 1 or greater; and

solving the perturbed differential equations to obtain one or more vibrational characteristics of the element with the discontinuity.

2. The process of claim 1, wherein the physical characteristics of the element comprise one or more of geometric and material characteristics of the element.

3. The process of claim 1, wherein the vibrational characteristics comprise one or more of mode shapes, natural frequencies, displacements, section-rotations, shears, moments, stresses and strains.

4. The process of claim 1, wherein the vibrational characteristics comprise one or more of displacement mode shapes, sectional-rotation mode shapes, derivatives of displacement mode shape, derivatives of sectional rotational mode shape, and combinations involving their sum or product.

5. The process of claim 1, wherein the element comprises a physical structure.

6. The process of claim 1, wherein the discontinuity comprises damage to the element.

7. The process of claim 1, wherein the element comprises more than one discontinuity.

8. The process of claim 1, wherein solving the perturbed differential equations to obtain the one or more vibrational characteristics of the element with the discontinuity comprises using a convolution integral in space domain over the domain of the discontinuity.

9-24. -24. (canceled)

25. A process of modeling a multi-element structure with finite element analysis, wherein at least one of the multi-elements has a discontinuity, the process to obtain one or more vibrational characteristics of the multi-element structure, the process comprising:

for each of the elements of the multi-elements having a discontinuity;

providing the physical characteristics of the element;

providing a finite element method code;

perturbing one or more vibrational characteristics of the element without the discontinuity based on the physical characteristics of the discontinuity;

calculating nth-order, perturbed differential equations governing one or more vibrational characteristics of the element with the discontinuity, wherein n is 1 or greater; and

forming a finite element based on the perturbed differential equations;

wherein the finite element is used with the finite method element code to obtain one or more vibrational characteristics of the entire multi-element structure;

wherein multi-element is three or more elements.

26. The process of claim 25, wherein the physical characteristics of each element comprises one or more of spatial, geometric and material characteristics of the element.

27. The process of claim 25, wherein the vibrational characteristics comprise one or more of mode shapes, natural frequencies, displacements, section-rotations, shears, moments, stresses and strains.

28. The process of claim 25, wherein the vibrational characteristics comprise one or more of displacement mode shapes, sectional-mode shapes, derivatives of displacement mode shape, derivatives of sectional rotational mode shape, and combinations involving their sum or product.

29. The process of claim 25, wherein each element comprises a physical structure.

30. The process of claim 25, wherein the discontinuity comprises damage to the element.

31. The process of claim 25, wherein forming a finite element comprises modeling the discontinuity as an equivalent (negative) stiffness.

32. The process of claim 25, wherein forming a finite element comprises modeling the discontinuity as an equivalent (negative) force.

42. The process of claim 25, wherein the multi-element structure is a three-dimensional multi-structural structure.

33-41. -41. (canceled)

43-64. -64. (canceled)

65. A process of designing a desired element without a discontinuity with one or more desired vibrational characteristics when related to the element modeled as having a discontinuity, the process comprising:

modeling an element with a discontinuity to obtain one or more vibrational characteristics of the element with the discontinuity, the process comprising;

providing the physical characteristics of the element;

providing one or more vibrational characteristics of the element without the discontinuity;

perturbing one or more vibrational characteristics of the element without the discontinuity based on characteristics of the discontinuity;

calculating nth-order, perturbed differential equations governing one or more vibrational characteristics of the element with the discontinuity, wherein n is 1 or greater; and

solving the perturbed differential equations to obtain one or more vibrational characteristics of the element with the discontinuity;

altering one or more vibrational characteristics of the element with the discontinuity with reference to the physical characteristics of the element; and

obtaining the desired element with one or more desired vibrational characteristics when related to the element having a discontinuity.

66. The process of claim 65, wherein obtaining the desired element with one or more desired vibrational characteristics when related to the element having a discontinuity does not utilize the physical properties of the discontinuity.

67. The process of claim 65, wherein altering one or more vibrational characteristics of the element with the discontinuity with reference to the physical characteristics of the element comprises equalization of one or more vibrational characteristics of the desired element with the same one or more vibrational characteristics of the element with the discontinuity.

68. The process of claim 65, wherein altering one or more vibrational characteristics of the element with the discontinuity with reference to the physical characteristics of the element comprises enhancing one or more vibrational characteristics of the desired element with reference to the same one or more vibrational characteristics of the element with the discontinuity.

69. The process of claim 65, wherein altering one or more vibrational characteristics of the element with the discontinuity with reference to the physical characteristics of the element comprises diminishing one or more vibrational characteristics of the desired element with reference to the same one or more vibrational characteristics of the element with the discontinuity.

70. The process of claim 65, wherein the physical characteristics of the element comprise one or more of spatial, geometric and material characteristics of the element.

71. The process of claim 65, wherein the vibrations characteristics comprise one or more of mode shapes, natural frequencies, displacements, sectional rotations, shears, moments, stresses and strains.

72. The process of claim 65, wherein the vibrations characteristics comprise one or more of displacement mode shapes, sectional rotation mode shapes, derivatives of displacement mode shape, derivatives of sectional rotational mode shape, and combinations involving their sum or product.

73. The process of claim 65, wherein the desired element comprises a physical structure.

74. The process of claim 65, wherein the discontinuity comprises damage to the element.

75. The process of claim 65, wherein the element comprises more than one discontinuity.

76-100. -100. (canceled)

101. A process for detecting a discontinuity in an element, wherein the element has one or more continuous parts, each with no discontinuity, and one or more discontinuous parts, each with a discontinuity, the process comprising:

providing one or more modeled vibrational characteristics of the element due to the one or more continuous parts of the element;

determining one or more vibrational characteristics of the element;

expressing the one or more determined vibrational characteristics of the element as a sum of the one or more modeled vibrational characteristics due to the one or more continuous parts of the element and one or more vibrational characteristics due to the one or more discontinuous parts of the element to obtain the one or more vibrational characteristics due to the one or more discontinuous parts of the element; and

isolating the one or more vibrational characteristics due to the one or more discontinuous parts of the element.

102. The process of claim 101, wherein the determined vibrational characteristics comprise one or more of mode shapes, natural frequencies, displacements, sectional rotations, shears, moments, stresses and strains.

103. The process of claim 101, wherein the determined vibrational characteristics comprise one or more of displacement mode shapes, sectional rotation mode shapes, derivatives of displacement mode shape, derivatives of sectional rotational mode shape, and combinations involving their sum or product.

104. The process of claim 101, wherein the element comprises a physical structure.

105. The process of claim 101, wherein the discontinuity comprises damage to the element.

106. The process of claim 101, wherein the element comprises more than one discontinuity.

107-218. -218. (canceled)