scholarly journals Development of an automated assessment technology for detecting damage in body armour

2020 ◽  
Vol 234 (20) ◽  
pp. 4116-4125
Author(s):  
Ryan Marks ◽  
Stephen Grigg ◽  
Davide Crivelli ◽  
Matthew Pearson ◽  
Mark Eaton ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Ultrasonic Waves ◽  
Baseline Measurement ◽  
Automated Assessment ◽  
Central Location ◽  
Body Armour ◽  
Low Profile ◽  
The Impact ◽  
Plate Current

Hard ballistic body armour plates are designed to withstand the impact of a bullet and protect the wearer, if this happens the armour is clearly damaged and so is retired from service. Mishandling, however, such as dropping the armour, may cause minor and difficult to detect damage which compromises the effectiveness of the plate. Current methods of inspection involve shipping the plates to a central location, performing a thorough inspection and returning them to service if uncompromised; this is costly and requires redundancy of equipment for when not in service. Acousto-Ultrasonics is a method of structural health monitoring in which ultrasonic waves are excited in a structure by a transducer and receivers record the response, any deviation from a baseline measurement give an indication of damage within the structure. Within this paper the development and testing of a novel handheld prototype device is presented, which gives a simple yes/no answer to if there is damage on the plate. This inspection is quick and easy to perform by unskilled personnel. Low profile sensors have been utilised combined with a novel flexible circuitry with built in memory, which does not compromise the effectiveness of the armour.

Structural Health Monitoring of Research-Scale Wind Turbine Blades

2013 ◽  
Vol 558 ◽  
pp. 364-373 ◽  
Author(s):  
Stuart G. Taylor ◽  
Kevin M. Farinholt ◽  
Gyu Hae Park ◽  
Charles R. Farrar ◽  
Michael D. Todd ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Embedded Systems ◽  
Wind Turbine ◽  
Health Monitoring ◽  
Turbine Blades ◽  
Field Tests ◽  
Ultrasonic Waves ◽  
Wind Turbine Blades ◽  
Structural Health ◽  
Sensing System

This paper presents ongoing work by the authors to implement real-time structural health monitoring (SHM) systems for operational research-scale wind turbine blades. The authors have been investigating and assessing the performance of several techniques for SHM of wind turbine blades using piezoelectric active sensors. Following a series of laboratory vibration and fatigue tests, these techniques are being implemented using embedded systems developed by the authors. These embedded systems are being deployed on operating wind turbine platforms, including a 20-meter rotor diameter turbine, located in Bushland, TX, and a 4.5-meter rotor diameter turbine, located in Los Alamos, NM. The SHM approach includes measurements over multiple frequency ranges, in which diffuse ultrasonic waves are excited and recorded using an active sensing system, and the blades global ambient vibration response is recorded using a passive sensing system. These dual measurement types provide a means of correlating the effect of potential damage to changes in the global structural behavior of the blade. In order to provide a backdrop for the sensors and systems currently installed in the field, recent damage detection results for laboratory-based wind turbine blade experiments are reviewed. Our recent and ongoing experimental platforms for field tests are described, and experimental results from these field tests are presented. LA-UR-12-24691.

scholarly journals Experimentation and Adaptive Modeling for Temperature Effect Quantification in PVP Structural Health Monitoring With PWAS

2015 ◽  
Author(s):  
Tuncay Kamas ◽  
Banibrata Poddar ◽  
Bin Lin ◽  
Lingyu Yu ◽  
Victor Giurgiutiu
Keyword(s):  
Elevated Temperature ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Thermal Effects ◽  
Guided Waves ◽  
Substrate Material ◽  
Ultrasonic Waves ◽  
Material Parameters ◽  
Structural Health

The thermal effects at elevated temperatures mostly exist for pressure vessel and pipe (PVP) applications. The technologies for diagnosis and prognosis of PVP systems need to take the thermal effect into account and compensate it on sensing and monitoring of PVP structures. One of the extensively employed sensor technologies has been permanently installed piezoelectric wafer active sensor (PWAS) for in-situ continuous structural health monitoring (SHM). Using the transduction of ultrasonic elastic waves into voltage and vice versa, PWAS has been emerged as one of the major SHM sensing technologies. However, the dynamic characteristics of PWAS need to be explored prior its installation for in-situ SHM. Electro-mechanical impedance spectroscopy (EMIS) method has been utilized as a dynamic descriptor of PWAS and as a high frequency local modal sensing technique by applying standing waves to indicate the response of the PWAS resonator by determining the resonance and anti-resonance frequencies. Another SHM technology utilizing PWAS is guided wave propagation (GWP) as a far-field transient sensing technique by transducing the traveling guided ultrasonic waves (GUW) into substrate structure. The paper first presents EMIS method that qualifies and quantifies circular PWAS resonators under traction-free boundary condition and in an ambience with increasing temperature. The piezoelectric material degradation was investigated by introducing the temperature effects on the material parameters that are obtained from experimental observations as well as from related work in literature. GWP technique is also presented by inclusion of the thermal effects on the substrate material. The MATLAB GUI under the name of Wave Form Revealer (WFR) was adapted for prediction of the thermal effects on coupled guided waves and dynamic structural change in the substrate material at elevated temperature. The WFR software allows for the analysis of multimodal guided waves in the structure with affected material parameters in an ambience with elevated temperature.

scholarly journals Structural Health Monitoring for cultural heritage constructions: a resilience perspective

2019 ◽  
Author(s):  
Maria Pina Limongelli ◽  
Zehra Irem Turksezer ◽  
Pier Francesco Giordano
Keyword(s):  
Structural Health Monitoring ◽  
Cultural Heritage ◽  
Health Monitoring ◽  
Social Value ◽  
Specific Reference ◽  
Structural Health ◽  
Heritage Constructions ◽  
The Impact ◽  
Support Decision Making ◽  
Over Time

<p>Disturbances or disruptive events may induce reductions of functionality of the built environment. For Cultural Heritage (CH) structures, functionalities may range from technical, to economic ones linked to touristic activities, up to intangible functionalities related to the cultural and social value of these constructions. Resilience can be defined as the capability of a system overcome a disturbance with the minimum total loss of functionality over time. Structural Health Monitoring (SHM) may enhance resilience by providing information that can support decision making, aiming to reduce the impact of the disturbances. In this paper, the benefits of SHM systems as means for improving resilience of CH structures are addressed and discussed with specific reference to the three different decision situations; before, during and after events of disturbances. Examples of real applications of SHM for CH structures and its effect on the resilience of the system conclude the paper.</p>

scholarly journals Improving sensitivity and coverage of structural health monitoring using bulk ultrasonic waves

2020 ◽  
pp. 147592172096512
Author(s):  
Stefano Mariani ◽  
Yuan Liu ◽  
Peter Cawley
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Temperature Compensation ◽  
Signal Amplitude ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Back Wall ◽  
Environmental Chamber ◽  
Structural Health ◽  
Specific Temperature

Practical ultrasonic structural health monitoring systems must be able to deal with temperature changes and some signal amplitude/phase drift over time; these issues have been investigated extensively with low-frequency-guided wave systems but much less work has been done on bulk wave systems operating in the megahertz frequency range. Temperature and signal drift compensation have been investigated on a thick copper block specimen instrumented with a lead zirconate titanate disc excited at a centre frequency of 2 MHz, both in the laboratory at ambient temperature and in an environmental chamber over multiple 20°C–70°C temperature cycles. It has been shown that the location-specific temperature compensation scheme originally developed for guided wave inspection significantly out-performs the conventional combined optimum baseline selection and baseline signal stretch method. The test setup was deliberately not optimised, and the signal amplitude and phase were shown to drift with time as the system was temperature cycled in the environmental chamber. It was shown that the ratio of successive back wall reflections at a given temperature was much more stable with time than the amplitude of a single reflection and that this ratio can be used to track changes in the reflection coefficient from the back wall with time. It was also shown that the location-specific temperature compensation method can be used to compensate for changes in the back wall reflection ratio with temperature. Clear changes in back wall reflection ratio were produced by the shadow effect of simulated damage in the form of 1-mm diameter flat-bottomed holes, and the signal-to-noise ratio was such that much smaller defects would be detectable.

An Impact-Based Experimental Setup for Evaluation of Rapid Electromechanical Impedance-Based Structural Health Monitoring

2020 ◽  
Author(s):  
Mohammad Alshaikh Ali ◽  
Eric C. Nolan ◽  
Steven R. Anton ◽  
Mohsen Safaei
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Sampling Rate ◽  
Frequency Resolution ◽  
Experimental Setup ◽  
Frequency Bandwidth ◽  
Electromechanical Impedance ◽  
Excitation Signal ◽  
Structural Health ◽  
The Impact

Abstract This work investigates the application of structural health monitoring (SHM) in a dynamic environment with the electromechanical impedance (EMI) method. Classically, the EMI method monitors civil or mechanical structures for damage in static environments. Advances in data acquisition (DAQ) now allow the possibility of rapid damage detection in dynamic environments. An impact-based experimental setup is developed to create a repeatable dynamic event through a collision between a pneumatically actuated striker bar and a static incident bar instrumented with a piezoelectric transducer. The EMI method is employed to detect the change of state at the interface of the two colliding bars. Experimental results prove the pneumatic launching system is capable of repeatable dynamic events, but the duration of contact is only 0.03 ms and the current DAQ system is incapable of detecting the event. A 3D printed programming material interface is placed at the location of impact to increase the duration of contact to approximately 1 ms. An excitation signal is created to continuously sweep a 0.5 ms chirp signal with a frequency bandwidth from 60–70 kHz (previously identified damage sensitive frequency bandwidth from static testing) for 7.5 seconds. Results indicate that due to the sampling rate and sweep time of the excitation signal, the frequency resolution is not adequate to properly assess if the impact is detected. Improvements in the DAQ hardware must be considered for future work.

scholarly journals Review of Structural Health Monitoring Methods Regarding a Multi-Sensor Approach for Damage Assessment of Metal and Composite Structures

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 826 ◽  
Author(s):  
Christoph Kralovec ◽  
Martin Schagerl
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Damage Assessment ◽  
Composite Structures ◽  
Joint Damage ◽  
Ultrasonic Waves ◽  
Physical Models ◽  
Monitoring Methods ◽  
Structural Health ◽  
Different Levels

Structural health monitoring (SHM) is the continuous on-board monitoring of a structure’s condition during operation by integrated systems of sensors. SHM is believed to have the potential to increase the safety of the structure while reducing its deadweight and downtime. Numerous SHM methods exist that allow the observation and assessment of different damages of different kinds of structures. Recently data fusion on different levels has been getting attention for joint damage evaluation by different SHM methods to achieve increased assessment accuracy and reliability. However, little attention is given to the question of which SHM methods are promising to combine. The current article addresses this issue by demonstrating the theoretical capabilities of a number of prominent SHM methods by comparing their fundamental physical models to the actual effects of damage on metal and composite structures. Furthermore, an overview of the state-of-the-art damage assessment concepts for different levels of SHM is given. As a result, dynamic SHM methods using ultrasonic waves and vibrations appear to be very powerful but suffer from their sensitivity to environmental influences. Combining such dynamic methods with static strain-based or conductivity-based methods and with additional sensors for environmental entities might yield a robust multi-sensor SHM approach. For demonstration, a potent system of sensors is defined and a possible joint data evaluation scheme for a multi-sensor SHM approach is presented.

Impact Detection Using an Array of Piezoelectric Wafer Active Sensors and a Microcontroller Unit

2010 ◽  
Author(s):  
Abraham Light-Marquez ◽  
Andrei Zagrai
Keyword(s):  
Structural Health Monitoring ◽  
Sensor Network ◽  
Health Monitoring ◽  
Detection System ◽  
Active Sensors ◽  
Structural Health ◽  
Impact Detection ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
The Impact

This report discusses the development of an embeddable impact detection system utilizing an array of piezoelectric wafer active sensors (PWAS) and a microcontroller. Embeddable systems are a critical component to successfully implement a complete and robust structural health monitoring system. System capabilities include impact detection, impact location determination and digitization of the impact waveform. A custom algorithm was developed to locate the site of the impact.. The embedded system has the potential for additional capabilities including advanced signal processing and the integration of wireless functionality. For structural health monitoring applications it is essential to determine the extent of damage done to the structure. In an attempt to determine these parameters a series of impact tests were conducted using a ball drop tower on a square aluminum plate. The response of the plate to the impact event was recorded using a piezoelectric wafer sensor network attached to the surface of the plate. From this testing it was determined that several of the impact parameters are directly correlated with the features recorded by the sensor network.

Structural health monitoring of cylindrical structures using guided ultrasonic waves

2012 ◽  
Vol 223 (8) ◽  
pp. 1669-1680 ◽  
Author(s):  
Lothar Gaul ◽  
Helge Sprenger ◽  
Christoph Schaal ◽  
Stefan Bischoff
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Ultrasonic Waves ◽  
Cylindrical Structures ◽  
Structural Health ◽  
Guided Ultrasonic Waves
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