Improved Damage Location Accuracy Using Strain Energy-Based Mode Selection Criteria

AIAA Journal ◽  
10.2514/2.159 ◽  
1997 ◽  
Vol 35 (4) ◽  
pp. 693-699 ◽  
Author(s):  
Scott W. Doebling ◽  
Francois M. Hemez ◽  
Lee D. Peterson ◽  
Charbel Farhat
Keyword(s):  
Strain Energy ◽  
Selection Criteria ◽  
Mode Selection ◽  
Location Accuracy ◽  
Damage Location

Improved damage location accuracy using strain energy-based mode selection criteria

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 693-699 ◽  
Author(s):  
Scott W. Doebling ◽  
Francois M. Hemez ◽  
Lee D. Peterson ◽  
Charbel Farhat
Keyword(s):  
Strain Energy ◽  
Selection Criteria ◽  
Mode Selection ◽  
Location Accuracy ◽  
Damage Location

scholarly journals Damage Detection of a Continuous Bridge from Response of a Moving Vehicle

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Z. H. Li ◽  
F. T. K. Au
Keyword(s):  
Genetic Algorithm ◽  
Damage Detection ◽  
Strain Energy ◽  
Identification Problem ◽  
Modal Strain Energy ◽  
Moving Vehicle ◽  
Second Stage ◽  
Damage Location ◽  
Damage Indicator ◽  
Vertical Accelerations

This paper presents a multistage multipass method to identify the damage location of a continuous bridge from the response of a vehicle moving on the rough road surface of the bridge. The vehicle runs over the bridge several times at different velocities and the corresponding responses of the vehicle can be obtained. The vertical accelerations of the vehicle running on the intact and damaged bridges are used for identification. The multistage damage detection method is implemented by the modal strain energy based method and genetic algorithm. The modal strain energy based method estimates the damage location by calculating a damage indicator from the frequencies extracted from the vehicle responses of both the intact and damaged states of the bridge. At the second stage, the identification problem is transformed into a global optimization problem and is solved by genetic algorithm techniques. For each pass of the vehicle, the method can identify the location of the damage until it is determined with acceptable accuracy. A two-span continuous bridge is used to verify the method. The numerical results show that this method can identify the location of damage reasonably well.

The Experimental Research of Delamination Damage Location Based on FBG Sensors Network in Solid Rocket Motor Shell

2009 ◽  
Vol 413-414 ◽  
pp. 47-54 ◽  
Author(s):  
Xin Long Chang ◽  
Xiang Yong He ◽  
Bin Jian ◽  
Zheng Liang Li
Keyword(s):  
Strain Field ◽  
Strain Energy ◽  
Rocket Motor ◽  
Strain Sensors ◽  
Least Square ◽  
Solid Rocket Motor ◽  
Moving Least Square ◽  
Damage Location ◽  
Solid Rocket ◽  
Delamination Damage

The fiber reinforced composite materials were widely used for aerospace aircrafts and missile weapons, and the delamination was a major problem which reduced the structural integrity and reliability of the solid rocket motor (SRM) composite shell seriously. In order to locate the delamination damage, the fiber Bragg grating (FBG) strain sensors network was embedded in SRM shell, and a multi-step approach of delamination damage location based on strain energy was performed: the strain field was measured in a scatter grid by the FBG strain sensors network in hydraulic testing; then the continuous displacement and strain field was reconstructed with relative sensors data using a moving least square (MLS) mesh-free fitting method; the strain energy of each subregions was calculated from the reconstructed data; finally the damaged subregions was identified successfully by singularity value of strain energy. The results of simulation and experiment indicated that the damage identification and location only required the measure of strain field of the SRM shell, and the presented approach achieved higher accuracy.

An Adapted Intra and Inter Prediction Algorithm for H.264

2015 ◽  
Vol 740 ◽  
pp. 830-833
Author(s):  
Yue Yue Wang ◽  
Yu Bin Cui
Keyword(s):  
Selection Criteria ◽  
Mode Selection ◽  
Selection Method ◽  
Prediction Algorithm ◽  
The Novel ◽  
Inter Prediction ◽  
Integer Transform ◽  
Transform Coefficients ◽  
Residual Block

An adapted prediction algorithm for H.264 is proposed in this paper. For I frames, a new intra algorithm is proposed in which a novel Intra_4×4 mode selection method is designed. Nine Intra_4×4 modes are divided into three classes, the suitable mode class for current 4×4-block is predicted using the mode classes of neighboring left and up blocks. For inter frames, a new inter prediction algorithm is proposed, and two matrixes which are composed of sum of absolute values of the integer transform coefficients in 4×4-residual-block contained in luminance 16×16-block and 8×8-block are defined respectively, the novel MB and sub-MB mode selection criteria which use the derived gradients of the two matrixes are then proposed.

Mode Selection for Offshore Platform Damage Identification Using CMSE Sensitivity

2019 ◽  
Author(s):  
Mingqiang Xu ◽  
Yuchi Liu ◽  
Yufeng Jiang ◽  
Shuqing Wang
Keyword(s):  
Structural Damage ◽  
Strain Energy ◽  
Damage Identification ◽  
Numerical Study ◽  
Mode Selection ◽  
Offshore Platform ◽  
Selection Strategy ◽  
Sensitivity Index ◽  
Modal Strain Energy ◽  
The Cross

Abstract A sensitivity-based mode selection strategy for cross modal strain energy (CMSE) method is proposed to identify damage more effectively. The cross modal strain energy sensitivity is defined as the sensitivity index. For this purpose, the cross modal strain energy sensitivity to structural damage is deduced, and is used to select the preferable mode combinations that are sensitive to damage. By using the preferable mode combinations, the CMSE system is refined and the degree of ill-posedness of the CMSE system is reduced. A numerical study is conducted on an offshore platform structure to demonstrate the effectiveness of the proposed scheme. The performances of the CMSE method with and without using the mode selection strategy are compared in the presence of noise. Results show that: (1) the accuracy of damage localization is improved when only a few mode combinations are utilized; (2) On account of excluding substantial low-sensitivity mode combinations, the amount of computation is significantly reduced.

An Experimental Appraisal of the Strain Energy Damage Location Method

2001 ◽  
Vol 204-205 ◽  
pp. 35-46 ◽  
Author(s):  
Keith Worden ◽  
Graeme Manson ◽  
D.J. Allman
Keyword(s):  
Strain Energy ◽  
Location Method ◽  
Damage Location

scholarly journals An Ultrasonic Guided Wave Mode Selection and Excitation Method in Rail Defect Detection

2019 ◽  
Vol 9 (6) ◽  
pp. 1170 ◽  
Author(s):  
Hongmei Shi ◽  
Lu Zhuang ◽  
Xining Xu ◽  
Zujun Yu ◽  
Liqiang Zhu
Keyword(s):  
Mode Shape ◽  
Strain Energy ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Rail Head ◽  
Ultrasonic Guided Wave ◽  
Phase Velocity Dispersion ◽  
Excitation Method ◽  
Shape Data

Different guided wave mode has different sensitivity to the defects of rail head, rail web and rail base in the detection of rail defects using ultrasonic guided wave. A novel guided wave mode selection and excitation method is proposed, which is effective for detection and positioning of the three parts of rail defects. Firstly, the mode shape data in a CHN60 rail is obtained at the frequency of 35 kHz based on SAFE method. The guided wave modes are selected, combining the strain energy distribution diagrams with the phase velocity dispersion curves of modes, which are sensitive to the defects of the rail head, rail web and rail base. Then, the optimal excitation direction and excitation node of the modes are calculated with the mode shape matrix. Phase control and time delay technology are employed to achieve the expected modes enhancement and interferential modes suppression. Finally, ANSYS is used to excite the specific modes and detect defects in different rail parts to validate the proposed methods. The results show that the expected modes are well acquired. The selected specific modes are sensitive to the defects of different positions and the positioning error is small enough for the maintenance staff to accept.

The wustite-spinel interface

1987 ◽  
Vol 45 ◽  
pp. 268-269
Author(s):  
S.R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Strain Energy ◽  
Matrix Material ◽  
Lattice Misfit ◽  
Solid State Reactions ◽  
Oxygen Sublattice ◽  
Large Particles ◽  
Small Lattice ◽  
Coherent Interfaces

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.

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