scholarly journals Development of Time-Reversal Method for Impact Source Identification on Plate Structures

2013 ◽  
Vol 20 (3) ◽  
pp. 561-573 ◽  
Author(s):  
Chunlin Chen ◽  
Yulong Li ◽  
Fuh-Gwo Yuan
Keyword(s):  
Impact Loading ◽  
Time Reversal ◽  
Source Identification ◽  
Transfer Functions ◽  
Plate Thickness ◽  
Time History ◽  
Numerical Verification ◽  
Impact Location ◽  
Location Detection ◽  
The Impact

This paper presents a detailed study on the impact source identification of a plate structure using time-reversal (T-R) method. Prior to impact monitoring, the plate is calibrated (or characterized) by transfer functions at discrete locations on the plate surface. Both impact location and impact loading time-history are identified using T-R technique and associated signal processing algorithms. Numerical verification for finite-size isotropic plates under low velocity impacts is performed to demonstrate the versatility of T-R method for impact source identification. The tradeoff between accuracy of the impact location detection and calibration spacing is studied in detail. In particular, the effect of plate thickness on calibration spacing has been examined. A number of parameters selected for determining the impact location, approximated transfer functions and steps taken for reconstructing the impact loading time-history are also examined. Two types of noise with various intensities contaminated in strain response and/or transfer functions are investigated for demonstrating the stability and reliability of the T-R method. The results show that T-R method is robust against noise in impact location detection and force reconstruction in circumventing the inherent ill-conditioned inverse problem. Only transfer functions are needed to be calibrated and four sensors are requested in T-R method for impact identification.

Determination of impact events on a plate-like composite structure

2016 ◽  
Vol 120 (1228) ◽  
pp. 984-1004 ◽  
Author(s):  
L. Xu ◽  
Y. Wang ◽  
Y. Cai ◽  
Z. Wu ◽  
W. Peng
Keyword(s):  
Composite Structures ◽  
Transfer Functions ◽  
Flat Glass ◽  
Time History ◽  
Identification Algorithm ◽  
Impact Location ◽  
Force Time ◽  
The Impact ◽  
The Relationship ◽  
Impact Events

ABSTRACTComposite materials have been increasingly used in aircraft structures. However, these composite structures are susceptible to damage from external low-velocity impacts. In this paper, an impact identification algorithm is proposed to estimate the impact location and force time history simultaneously. A localisation method based on basis vectors is proposed, and the impact force time history is reconstructed by simplified transfer functions. The basis vector stands for the relationship between the impact location and the sensor signals, and the transfer function shows the relationship of the sensor signal and the force time history. An experiment is conducted on a flat glass fibre-epoxy matrix composite plate to verify the developed algorithm using only four sensors. The soft impactor and hard impactor are two typical impactors for impact events; therefore, the impact experiment is performed by the rubber and the steel impactors, respectively. The experimental results indicate that the proposed algorithm is feasible for the identification of impact events on plate-like composite structures.

An Enhanced Time-Reversal Method for Impact Damage Monitoring on Plate-Like Structures

2012 ◽  
Vol 525-526 ◽  
pp. 365-368
Author(s):  
Chun Lin Chen ◽  
Yu Long Li ◽  
Fuh Gwo Yuan
Keyword(s):  
Time Reversal ◽  
Composite Structures ◽  
Impact Damage ◽  
High Energy ◽  
Low Velocity ◽  
Energy Impact ◽  
Location Detection ◽  
Focusing Property ◽  
The Impact ◽  
Impact Events

Based on the self-focusing property of time-reversal (T-R) concept, a time focusing parameter was suggested to improve the impact source identification method developed in authors previous work. This paper presents a further study on monitoring relatively high energy impact events which caused induced damage on structures. Numerical verifications for a finite isotropic plate and a composite plate under low velocity impacts are performed to demonstrate the versatility of T-R method for impact location detection with induced plastic deformation and delamination damage on metallic and composite structures respectively. The focusing property of T-R concept was adequately utilized to detect impact/damage location. The results show that impact events with various features can be localized using T-R method by introducing the time focusing parameter. It is suited to monitor serious impact events on plate like structures in practice in future.

scholarly journals Experiment and Simulation Study on the Dynamic Response of RC Slab under Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yue Wang ◽  
Jun Liu ◽  
Zhimin Xiao ◽  
Futian Zhao ◽  
Yi Cheng
Keyword(s):  
Dynamic Response ◽  
Impact Loading ◽  
Impact Resistance ◽  
Great Influence ◽  
Time History ◽  
Reinforcement Ratio ◽  
Slab Thickness ◽  
Drop Hammer ◽  
Rc Slab ◽  
The Impact

Reinforced concrete (RC) slab is an important component in civil construction and protection engineering, and its dynamic response under impact loading is a complex mechanical problem, especially for two or multiple continuous impact loads. In this paper, a series of drop hammer impact tests were carried out to investigate the dynamic response of RC slabs with two successive impacts. The time history of impact force and the failure characteristic of the slab surface were recorded. Moreover, four influence factors, including slab thickness, reinforcement ratio, impact location, and drop hammer height have been discussed. Besides, a 3D numerical model based on the finite element method (FEM) was established to expand the research of constrained force, deflection, and vertical stress of an RC slab. The results show that increasing the slab thickness and reinforcement ratio can improve the impact resistance of an RC slab. The impact point location and drop hammer height have a great influence on the dynamic response of the RC slab. In addition, the RC slab will have more obvious damage under the second impact, but the dynamic response becomes weaker. It may be because of the local damage in the concrete caused by the first impact that would weaken the propagation of vibration.

Some Issues in Passive Impact Location Detection Triangulation in Composite Materials Using Embedded Piezoelectric Sensors

2012 ◽  
Author(s):  
Bruno Zamorano-Senderos ◽  
Niell Elvin ◽  
Samuel Shin
Keyword(s):  
Evaluation Method ◽  
Residual Life ◽  
Impact Damage ◽  
Computational Cost ◽  
Piezoelectric Sensors ◽  
New Technique ◽  
Impact Location ◽  
Location Detection ◽  
Extent Of Damage ◽  
The Impact

This paper studies some aspects of impact location detection in composites materials using triangulation methods with embedded piezoelectric sensors. The first step of any impact damage evaluation method is to ascertain if an impact has happened and its location. More sophisticated methods (not addressed in this paper) can then be used to determine the type and extent of damage and to estimate the residual life of the structure. We propose a novel sensor array that potentially reduces the number of computations required to locate the position of the impact and reduces the complexity of embedded sensor wiring. Reducing the computational complexity allows the use of lighter, cheaper and less energy consuming electronic devices. The new technique reduces the classical computation from a planar (two dimensional) search to an angular (one dimensional) search. The new technique is experimentally compared with a classical triangulation technique at moderate ballistic speeds (300 m/s). This paper shows that the new technique reduces the computational cost, but also reduces accuracy of impact location.

Impact source identification for pipe structure based on a one-dimensional fiber Bragg grating sensor array

2017 ◽  
Vol 28 (12) ◽  
pp. 1662-1669 ◽  
Author(s):  
Yeon-Gwan Lee ◽  
Chun-Gon Kim
Keyword(s):  
Fiber Bragg Grating ◽  
Source Identification ◽  
Sensor Array ◽  
Bragg Grating ◽  
One Dimensional ◽  
Fiber Bragg Grating Sensors ◽  
Sensor Arrangement ◽  
Impact Location ◽  
Bragg Grating Sensor ◽  
The Impact

This article presents a spatial impact source identification based on a one-dimensional fiber Bragg grating sensor array for application in tubular structures. The effective number of sensors and the sensor arrangement method were investigated for the plumbing pipe structure as the application subject. The fiber Bragg grating sensors were used to determine the impact location via the signal processing of the measured acoustic emission signals with a sampling frequency of 100 kHz. The root mean squared value–based algorithm, which was newly verified for a stiffened composite structure, was employed to identify the impact source in this article. Impact source identification was implemented according to the sensor arrangement and number of sensors, which were selectively used on the pipe structure among six multiplexed fiber Bragg grating sensors in one optical fiber line. This process shows that impact location detection is possible with only a one-dimensional sensor array compared to the results of a two-dimensional sensor array. The impact location could be predicted within a maximum error range of 31.12 mm, even if only one sensor was used to identify the impact source.

Improvement of Impact Identification Capability of Time Reversal Processing Using Experimentally Measured Surface Bonded PZT Sensor Signals

2007 ◽  
Author(s):  
Kazuhiko Adachi ◽  
Syota Horiuchi
Keyword(s):  
Impact Loading ◽  
Time Reversal ◽  
Structural Damage ◽  
Back Propagation ◽  
Scattered Wave ◽  
Processing Method ◽  
Sensor Signal ◽  
Time Duration ◽  
Sensor Signals ◽  
The Impact

In this study, the effect of time duration of the measured sensor signal to the impact identification capability of time reversal processing method is experimentally demonstrated. Time reversal processing for the measured sensor signal can be applied to detect not only structural damage but also impact loading of the structure. After measuring the electrical sensor signals corresponding to scattered wave filed of the plate experimentally, time reversal processing is applied to the measured signals in the numerical wave back propagation simulation for localizing the impact loading point on the plate. A time-reversed wave travels back through the plate and is focused on the region around a point where hits by the impact hammer. The illustrative experimental and numerical processes demonstrated the impact identification capability of time reversal processing method. Even if the measured signals were missing the wave front induced by the impact, the signal to noise ratio of the backward process was successfully improved by using the long time duration of the measured sensor signals.

Experimental Investigation Into the Effect of Impact Loading on the Response of Metallic Trapezoidal Corrugated Core Sandwich Panels

2018 ◽  
Author(s):  
Haifu Yang ◽  
Yuansheng Cheng ◽  
Pan Zhang ◽  
Jun Liu ◽  
Kai Chen
Keyword(s):  
Dynamic Response ◽  
Impact Energy ◽  
Impact Loading ◽  
Sandwich Panels ◽  
Low Velocity Impact ◽  
Front Face ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Location ◽  
The Impact

Sandwich structures with corrugated cores have attracted a lot of interest from industrial and academic fields due to their superior crashworthiness. In this paper, the dynamic response of metallic trapezoidal corrugated core sandwich panels under low-velocity impact loading is studied by conducting drop hammer impact testing. The sandwich panels composed of two thin face skins and trapezoidal corrugated core, were designed and fabricated through folding and laser welding technology. Main attention of present study was placed at the influences of the impact energy, impactor diameter and impact location on the impact force, deformation mechanisms and the permanent deflections of the trapezoidal corrugated core sandwich panels. Results revealed that the impact energy has significant effects on the dynamic response of the sandwich panel, whereas the impact diameter has little effects on it. The deformation mode of the front face sheet differs sharply when the impact location is different. The middle unit cell of corrugated core is compressed to the “M” shape under different low-velocity impact loading.

scholarly journals Investigation of the Impact of Seed Record Selection on Structural Response

2010 ◽  
Author(s):  
Thomas W. Houston ◽  
Greg E. Mertz ◽  
Michael C. Costantino ◽  
Carl J. Costantino
Keyword(s):  
Transfer Functions ◽  
Structural Response ◽  
Time History ◽  
Response Spectra ◽  
Recent Experience ◽  
Target Response ◽  
Target Spectrum ◽  
Time Histories ◽  
Record Selection ◽  
The Impact

Time history records are typically used to define the seismic demand for critical structures for which soil structure interaction (SSI) analyses are often required. Criteria for the development of time histories is provided in ASCE 43-05. The time histories are based on a close fit of 5% damped target response spectra. Recent experience has demonstrated that for cases where the transfer functions associated with the structural response are narrow, the ASCE 43-05 criteria can under-predict peak spectral responses in the structure by as much as 70% in some frequency ranges. One potential solution for this issue is to reinstate requirements for matching target response spectra for multiple damping levels to ASCE 43-05 criteria. However, recent probabilistic seismic hazard analyses (PSHA) do not generally contain spectra for multiple damping levels. This paper proposes an approach to generate target spectra at multiple damping levels, given the 5% damped target spectrum provided by the PSHA, utilizing catalogs of recorded earthquakes. The process of fitting time histories to multiple damped spectra is effective in correcting defficiencies observed in the computed structural response when time histories meeting the ASCE 43-05 fitting criteria are used.

scholarly journals Sensitivity Analysis of Steel-Plate Concrete Containment against a Large Commercial Aircraft

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2829
Author(s):  
Xiuyun Zhu ◽  
Jianbo Li ◽  
Gao Lin ◽  
Rong Pan ◽  
Liang Li
Keyword(s):  
Sensitivity Analysis ◽  
Plastic Strain ◽  
Steel Plate ◽  
Concrete Strength ◽  
Plate Thickness ◽  
Time History ◽  
Commercial Aircraft ◽  
Strength Grade ◽  
Displacement Response ◽  
The Impact

Due to the excellent impact resistant performance of steel-plate concrete (SC) structure compared with the conventional reinforced concrete (RC) structure, SC structure is preferred to be used in the design of external walls of nuclear island buildings for new nuclear power plants (NPPs). This study aims at evaluating the effect of material and geometric parameters of SC containment on its impact resistant performance, thus the numerical simulation and sensitivity analysis of SC containment subjected to malicious large commercial aircraft attack are conducted based on the force time-history analysis method. The results show that: (1) the impact resistant performance of full SC containment is better than that of half SC containment; (2) for relatively thin full SC containment, the impact response and concrete damage can be significantly reduced by the enhancing of concrete strength grade or the increasing of steel plate thickness; (3) for the thicker full SC containment, concrete strength grade has only a slight influence on the impact displacement response, and the increasing of steel plate thickness has no significant effect on mitigating the impact displacement response. However, the increasing of steel plate thickness can effectively reduce its plastic strain, and the decreasing of strength grade of steel plate may obviously increase its plastic strain; and (4) concrete thickness plays a decisive role on the improvement of impact resistance, which is more effective than the enhancing of concrete strength grade. Resultantly, this paper provides a reference and guidance for the design of SC structure external walls of nuclear island buildings against a large commercial aircraft.

scholarly journals Nanopore creation in MoS2 and graphene monolayers by nanoparticles impact: a reactive molecular dynamics study

2021 ◽  
Vol 127 (7) ◽  
Author(s):  
Hamidreza Noori ◽  
Bohayra Mortazavi ◽  
Leila Keshtkari ◽  
Xiaoying Zhuang ◽  
Timon Rabczuk
Keyword(s):  
Molecular Dynamics ◽  
Impact Loading ◽  
Impact Resistance ◽  
Time History ◽  
Single Layer ◽  
Resistance Force ◽  
Graphene Monolayer ◽  
Reactive Molecular Dynamics ◽  
Dynamics Simulations ◽  
The Impact

AbstractIn this work, extensive reactive molecular dynamics simulations are conducted to analyze the nanopore creation by nanoparticles impact over single-layer molybdenum disulfide (MoS2) with 1T and 2H phases. We also compare the results with graphene monolayer. In our simulations, nanosheets are exposed to a spherical rigid carbon projectile with high initial velocities ranging from 2 to 23 km/s. Results for three different structures are compared to examine the most critical factors in the perforation and resistance force during the impact. To analyze the perforation and impact resistance, kinetic energy and displacement time history of the projectile as well as perforation resistance force of the projectile are investigated. Interestingly, although the elasticity module and tensile strength of the graphene are by almost five times higher than those of MoS2, the results demonstrate that 1T and 2H-MoS2 phases are more resistive to the impact loading and perforation than graphene. For the MoS2nanosheets, we realize that the 2H phase is more resistant to impact loading than the 1T counterpart. Our reactive molecular dynamics results highlight that in addition to the strength and toughness, atomic structure is another crucial factor that can contribute substantially to impact resistance of 2D materials. The obtained results can be useful to guide the experimental setups for the nanopore creation in MoS2or other 2D lattices.

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