scholarly journals Transducer Placement Option of Lamb Wave SHM System for Hotspot Damage Monitoring

Aerospace ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 39 ◽  
Author(s):  
Vincentius Ewald ◽  
Roger Groves ◽  
Rinze Benedictus
Keyword(s):  
Lamb Wave ◽  
Damage Monitoring ◽  
Placement Option ◽  
Transducer Placement

scholarly journals An Aircraft Pallet Damage Monitoring Method Based on Damage Subarea Identification and Probability-Based Diagnostic Imaging

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Bin Liu ◽  
Tingzhang Liu ◽  
Yue Lin ◽  
Jianfei Zhao
Keyword(s):  
Diagnostic Imaging ◽  
Lamb Wave ◽  
Damage Index ◽  
Imaging Method ◽  
Monitoring Method ◽  
Study Results ◽  
Damage Monitoring ◽  
Weighted Algorithm ◽  
Damage Simulation ◽  
Monitoring Area

To improve the safety and economy of aircraft pallet use, an aircraft pallet damage monitoring method based on damage subarea identification and probability-based diagnostic imaging is proposed. In the proposed method, first, the large aircraft pallet monitoring area is divided into rectangular subareas, and a piezoelectric transducer sensor is pasted on each vertex of the rectangular subarea that is used to excitation and sensing the Lamb wave. Second, the damage subarea is identified according to the diagonal damage indexes. Third, the damage position in the damage subarea is calculated using the probability-based diagnostic imaging method and coordinate probability weighted algorithm. Finally, the aircraft pallet damage can be localized based on the damage subarea position. Frequency selection and damage simulation study results show that the Lamb wave is sensitive to aircraft pallet damage whose centre frequency ranges from 50 kHz to 150 kHz, and the damage index of a steel ball is less than that of all real aircraft pallet damage from 95 kHz to 125 kHz. The verification results show that the proposed method can locate aircraft pallet damage with an error of less than 2 cm.

scholarly journals Frequency Aliasing-Based Spatial-Wavenumber Filter for Online Damage Monitoring

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bin Liu ◽  
Tingzhang Liu ◽  
Jianfei Zhao ◽  
Dan Hang
Keyword(s):  
Lamb Wave ◽  
Sensor Array ◽  
Laminate Plate ◽  
Sampling Theorem ◽  
Spatial Sampling ◽  
Filter Method ◽  
Damage Monitoring ◽  
Shannon Sampling Theorem ◽  
Damage Imaging ◽  
Frequency Aliasing

The spatial-wavenumber filter method can extract the specific mode of the Lamb wave, thereby distinguishing the incident wave and the damage reflection wave. This method has been widely studied for damage imaging. However, the diameter of piezoelectric transducer (PZT) sensor limits the spatial sampling wavenumber of the linear PZT sensor array, which limits the application of this method because of the Nyquist–Shannon sampling theorem. Therefore, the wavenumber filtering range of spatial-wavenumber filter should be less than half of the spatial sampling wavenumber. In this paper, a frequency aliasing based spatial-wavenumber filter for online damage monitoring is proposed. In this method, the wavenumber filtering range is extended to the spatial sampling wavenumber, and two wavenumber results will be calculated as for the frequency aliasing. Subsequently, the wavenumber of the received Lamb wave signal can be obtained according to the average arrival time difference between the two adjacent sensors in the linear PZT sensor array. Finally, the damage is localized using the spatial-wavenumber filter and cruciform PZT sensor array. This method was validated on an epoxy laminate plate. The maximum damage localization errors are less than 2 cm. It is indicated that this method can extend the spatial-wavenumber filtering range to the spatial sampling wavenumber and the application of spatial-wavenumber filter-based online damage monitoring.

Impedance Analyzer Design Based on EMI and Lamb Wave

2014 ◽  
Vol 529 ◽  
pp. 506-510 ◽  
Author(s):  
Yu Xiang Zhang ◽  
Xin Zhang ◽  
Shi Yi Chen ◽  
Jia Zhao Chen
Keyword(s):  
Health Monitoring ◽  
Lamb Wave ◽  
Detection Method ◽  
Specific Structure ◽  
Impedance Analyzer ◽  
Wave Technology ◽  
Damage Monitoring ◽  
Single Method ◽  
Active Detection

EMI and the Lamb Wave technology are two kinds of mainstream active detection method in health monitoring , which have a long-term development. Health monitoring based on the combination of the EMI technology and Lamb wave, can be either a single method to conduct monitoring and analysis of specific structure ,or two methods together to conduct more comprehensive damage monitoring.

A Method of 3D Braided Composites Damage Monitoring

2015 ◽  
Vol 743 ◽  
pp. 861-865 ◽  
Author(s):  
Hua Zhang ◽  
Y.C. Xiao ◽  
Ming Li ◽  
G.Q. Liu ◽  
Jie Zhang
Keyword(s):  
Lamb Wave ◽  
Damage Index ◽  
Piezoelectric Sensors ◽  
Energy Change ◽  
Fatigue Load ◽  
Braided Composites ◽  
Index Method ◽  
Signal Energy ◽  
3D Braided Composites ◽  
Damage Monitoring

L shaped braided composites under fatigue load was researched, using piezoelectric sensors and active Lamb wave monitoring technology. HHT transform based signal envelope obtaining method and the damage index method based on signal energy change were used to monitor the damage extending of the braided composites.

scholarly journals Transducer Placement Option of Lamb Wave SHM System for Hotspot Damage Monitoring

2018 ◽  
Author(s):  
Vincentius Ewald ◽  
Roger M Groves ◽  
Rinze Benedictus
Keyword(s):  
Lamb Wave ◽  
High Stress ◽  
Fe Model ◽  
Fe Modelling ◽  
Detection Algorithms ◽  
Blob Detection ◽  
Sensor Position ◽  
Lamb Wave Propagation ◽  
Damage Tolerant ◽  
Transducer Placement

In this paper, we investigated transducer placement strategies for detecting crack in primary aircraft structures using ultrasonic Structural Health Monitoring (SHM). The approach developed is for an expected damage location based on fracture mechanics, for example fatigue crack growth in a high stress location. To assess the performance of the developed approach, finite-element (FE) modelling of a damage tolerant aluminum fuselage has been performed by introducing an artificial crack at a rivet hole into the structural FE model and assessing its influence on the Lamb wave propagation, compared to a baseline measurement simulation. The efficient practical sensor position was determined from the largest change in area that is covered by reflected and missing wave scatter using an additive color model. Blob detection algorithms were employed in order to determine the boundaries of this area and to calculate the blob centroid. To demonstrate that the technique can be generalized, the results from different crack lengths and from tilted crack are also presented.

Application of Marginal Spectrum in Active Lamb Wave Damage Monitoring of Plate Structure

2014 ◽  
Vol 490-491 ◽  
pp. 1698-1701 ◽  
Author(s):  
Bao Chun Xu ◽  
Mu Lan Wang ◽  
Qian Jia
Keyword(s):  
Health Monitoring ◽  
Lamb Wave ◽  
Monitoring Technology ◽  
Plate Structure ◽  
Damage Monitoring ◽  
Before And After ◽  
Marginal Spectrum ◽  
Scattering Signal

In this study, the marginal spectrum based on instantaneous parameter is applied to the active Lamb wave-based health monitoring of plate structure to investigate the marginal spectrum variation of the signals after being added with damage scattering signal. First,the active Lamb wave monitoring technology is employed to obtain the Lamb wave signals of the plate before and after damage. Then the marginal spectra of the signals before and after damage are obtained using the HHT technology and compared with the spectrum of the signals. The results show that the marginal spectrum can better describe the variation of the signals before and after damage.

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