Damage detection from changes in curvature mode shapes
08 Mar 1991-Journal of Sound and Vibration (JOURNAL OF SOUND AND VIBRATION)-Vol. 145, Iss: 2, pp 321-332
TL;DR: In this article, a new parameter called curvature mode shape is investigated as a possible candidate for identifying and locating damage in a structure, and it is shown that the absolute changes in the curvature shape are localized in the region of damage and hence can be used to detect damage.
About: This article is published in Journal of Sound and Vibration.The article was published on 1991-03-08. It has received 1924 citations till now. The article focuses on the topics: Curvature & Normal mode.
Citations
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01 May 1996
TL;DR: A review of the technical literature concerning the detection, location, and characterization of structural damage via techniques that examine changes in measured structural vibration response is presented in this article, where the authors categorize the methods according to required measured data and analysis technique.
Abstract: This report contains a review of the technical literature concerning the detection, location, and characterization of structural damage via techniques that examine changes in measured structural vibration response. The report first categorizes the methods according to required measured data and analysis technique. The analysis categories include changes in modal frequencies, changes in measured mode shapes (and their derivatives), and changes in measured flexibility coefficients. Methods that use property (stiffness, mass, damping) matrix updating, detection of nonlinear response, and damage detection via neural networks are also summarized. The applications of the various methods to different types of engineering problems are categorized by type of structure and are summarized. The types of structures include beams, trusses, plates, shells, bridges, offshore platforms, other large civil structures, aerospace structures, and composite structures. The report describes the development of the damage-identification methods and applications and summarizes the current state-of-the-art of the technology. The critical issues for future research in the area of damage identification are also discussed.
2,916 citations
TL;DR: In this paper, the authors provide an overview of methods to detect, locate, and characterize damage in structural and mechanical systems by examining changes in measured vibration response, including frequency, mode shape, and modal damping.
Abstract: This paper provides an overview of methods to detect, locate, and characterize damage in structural and mechanical systems by examining changes in measured vibration response. Research in vibration-based damage identification has been rapidly expanding over the last few years. The basic idea behind this technology is that modal parameters (notably frequencies, mode shapes, and modal damping) are functions of the physical properties of the structure (mass, damping, and stiffness). Therefore, changes in the physical properties will cause detectable changes in the modal properties. The motivation for the development of this technology is presented. The methods are categorized according to various criteria such as the level of damage detection provided, model-based versus non-model-based methods, and linear versus nonlinear methods. The methods are also described in general terms including difficulties associated with their implementation and their fidelity. Past, current, and future-planned applications of this technology to actual engineering systems are summarized. The paper concludes with a discussion of critical issues for future research in the area of vibration-based damage identification.
2,715 citations
Cites background from "Damage detection from changes in cu..."
...Baruch and Bar Itzhack (1978), Kabe (1985), and Berman and Nagy (1983) have a common formulation of the optimal update problem that is essentially minimization of the Frobenius norm of global parameter matrix perturbations using zero modal force error and property matrix symmetry as constraints....
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TL;DR: A comprehensive review on modal parameter-based damage identification methods for beam- or plate-type structures is presented in this paper, and the damage identification algorithms in terms of signal processing are discussed.
Abstract: A comprehensive review on modal parameter-based damage identification methods for beam- or plate-type structures is presented, and the damage identification algorithms in terms of signal processing...
1,613 citations
TL;DR: In this paper, a crack in a structural member introduces a local flexibility that affects its vibration response, and the crack will open and close in time depending on the rotation and vibration amplitude.
1,080 citations
Book•
19 Nov 2012
TL;DR: This book focuses on structural health monitoring in the context of machine learning and includes case studies that review the technical literature and include case studies.
Abstract: This book focuses on structural health monitoring in the context of machine learning. The authors review the technical literature and include case studies. Chapters include: operational evaluation, sensing and data acquisition, introduction to probability and statistics, machine learning and statistical pattern recognition, and data prognosis.
998 citations
References
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TL;DR: In this article, a method of non-destructively assessing the integrity of structures using measurements of the structural natural frequencies is described, where measurements made at a single point in the structure can be used to detect, locate and quantify damage.
Abstract: A method of non-destructively assessing the integrity of structures using measurements of the structural natural frequencies is described. It is shown how measurements made at a single point in the structure can be used to detect, locate and quantify damage. The scheme presented uses finite-element analysis, since this method may be used on any structure. The principle may, however, be used in conjunction with other mathematical techniques. Only one full analysis is required for each type of structure.Results are presented from tests on an aluminium plate and a cross-ply carbon-fibre-reinforced plastic plate. Excellent agreement is shown between the predicted and actual damage sites and a useful indication of the magnitude of the defect is obtained.
1,379 citations
TL;DR: In this paper, a method of non-destructively evaluating the integrity of structures is described and applied to structures for which a one dimensional analysis is satisfactory, and it is shown how vibration measureme...
Abstract: A method of non-destructively evaluating the integrity of structures is described and applied to structures for which a one dimensional analysis is satisfactory. It is shown how vibration measureme...
665 citations
TL;DR: In this article, the relationship between damage location, damage size and the changes in the eigenvalues and eigenvectors of a cantilever when subjected to damage is investigated.
253 citations
01 Jan 1989
TL;DR: In this paper, a flat plate structure with a rib stiffener bolted to it is used as the test specimen and modal tests are performed on it using an impact hammer, demonstrating the sensitivity of modal parameters to physical changes.
Abstract: Modal testing has become commonplace in many industries today as a research and development tool. In this capacity, it is used primarily during product prototype development and for trouble-shooting noise and vibration problems in general. Very little use has been made of this technology to date, though, for detecting faults in mechanical structures. By "faults," we mean any of the following occurrences: • Failure of the structural material, e.g., cracking or breaking. • Loosening of assembled parts. • Flaws, voids, cracks, thin spots, etc. caused during manufacturing. • Improper assembly of parts during manufacturing. In this paper, the correlation between a physical change and changes in the structure's modal parameters is investigated. A flat plate structure with a rib stiffener bolted to it is used as the test specimen and modal tests are performed on it using an impact hammer. This paper not only includes discussion about the advantages of using experimental modal data as a means of detecting structural faults, but also includes demonstrations of the sensitivity of modal parameters to physical changes. Specifically, it is shown how modal parameters can detect variations in the bolt tightness between the plate and the rib.
78 citations
TL;DR: In this paper, a vibration technique is evaluated as a nondestructive test tool under static and dynamic torsional loading, and cracks are observed in carbon and glass fiber reinforced plastic.
Abstract: Certain failures, such as resin bound shear cracks in fiber-reinforced materials, give rise to little change in ultrasonic attenuation or radiographic transmission but can result in significant reductions in material properties. A vibration technique is being evaluated as a nondestructive test tool under such conditions. The work described forms the first part of this evaluation program and concerns unidirectional carbon and glass fiber reinforced plastic subjected to static and dynamic torsional loading. The results and techniques will eventually be applied to complex composite structures. In the static torsion test program, 'good,' void-free specimens failed at shear stresses of between 52 and 60 MN/m 2 (carbon fiber) and between 56 and 62 MN/m 2 (glass fiber) in a very brittle manner. The cracks thus generated led to substantial changes in the dynamic (vibration) test data. Specimens containing voids failed at lower shear stresses and less catastrophically. In torsional fatigue, all failures occurred by the propagation of resin-bound shear cracks at shear stresses below the static strength of the material. The dynamic (vibration) test parameters showed permanent and progressive changes due to the accumulation of fatigue damage. Crack development was observed visually in the glass fiber specimens and broadly related to the changes in the dynamic properties.
77 citations