Electro-Mechanical Impedance Measurements in an Imitated Low Earth Orbit Radiation Environment

2016 ◽  
Author(s):  
Mary L. Anderson ◽  
Joshua D. Daniel ◽  
Andrei N. Zagrai ◽  
David J. Westpfahl
Keyword(s):  
Gamma Radiation ◽  
Radiation Exposure ◽  
Health Monitoring ◽  
Piezoelectric Ceramic ◽  
Absorbed Dose ◽  
Mechanical Impedance ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Piezoelectric Sensors ◽  
Aluminum Beam

Piezoelectric sensors are used in many structural health monitoring (SHM) methods to interrogate the condition of the structure to which the sensors are affixed or imbedded. Among SHM methods utilizing thin wafer piezoelectric sensors (PWAS), electro-mechanical impedance monitoring is seen as a promising approach to assess structural condition in the vicinity of a sensor. Using the converse and direct piezoelectric effects, this health monitoring method utilizes mechanical actuation and electric voltage to determine the impedance signature of the structure. If there is damage to the structure, there will be a change in the impedance signature. It is important to discern between actual damage and environmental effects on the piezoelectric ceramic sensors and the structure. If structural health monitoring is to be implemented in space structures on orbit, it is imperative to determine the effects of the extreme space environment on piezoelectric sensors and the structures to which they are affixed. The space environment comprises extreme temperatures, vacuum, atomic oxygen, microgravity, micro-meteoroids and debris, and significant amounts of radiation. Radiation in space comes from three sources: solar events, background cosmic radiation, and trapped particles in the Van Allen Belts. Radiation exposure to structures on orbit will vary significantly depending on the duration of the flight and the altitude and inclination of the orbit. In this contribution, the effect of gamma radiation on piezoelectric ceramic sensors and space grade aluminum is investigated for equivalent gamma radiation exposure to 3-months, six-months, and 1-year on Low Earth Orbit (LEO). An experiment was conducted at White Sands Missile Range, Gamma Radiation Facility using Cobalt-60 as the source of radiation. A free PWAS and a PWAS bonded to a small aluminum beam were exposed to increasing levels of gamma radiation. Impedance data were collected for both sensors after each radiation exposure. The total radiation absorbed dose was 200 kRad (Si) by the end of the experiment. The results show that piezoelectric ceramic material is affected by gamma radiation. Over the course of increasing exposure levels to Cobalt-60, the impedance frequency of the free sensor increased with each absorbed dose. The impedance measurements of the sensor bonded to the aluminum beam reflects structural and sensor’s impedance. The data for this sensor show an increase in impedance amplitude with each level of absorbed dose. The mechanism at work in these impedance changes is suggested and future experimental work is identified. A survey of previous results of radiation exposure of piezoelectric ceramic sensors and aluminum alloys is presented and are compared to previous studies.

Investigating Effect of Space Radiation Environment on Piezoelectric Sensors: Cobalt-60 Irradiation Experiment

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Mary Anderson ◽  
Andrei N. Zagrai ◽  
Joshua D. Daniel ◽  
David J. Westpfahl ◽  
Dale Henneke
Keyword(s):  
Gamma Radiation ◽  
Radiation Exposure ◽  
Piezoelectric Ceramic ◽  
Structural Damage ◽  
Space Radiation ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Piezoelectric Sensors ◽  
Radiation Environment ◽  
Space Radiation Environment

Piezoelectric sensors are used in many structural health monitoring (SHM) methods to interrogate the condition of the structure to which the sensors are affixed or embedded. Among SHM methods utilizing thin wafer piezoelectric sensors, embedded ultrasonics is seen as a promising approach to assess condition of space structures. If SHM is to be implemented in space vehicles, it is imperative to determine the effects of the extreme space environment on piezoelectric sensors in order to discern between actual structural damage and environmental effects. The near-Earth space environment comprises extreme temperatures, vacuum, atomic oxygen, microgravity, micrometeoroids and debris, and significant amounts of radiation. Gamma radiation can be used to emulate the space radiation environment. In this contribution, the effects of gamma radiation on piezoelectric ceramic sensors are investigated for equivalent gamma radiation exposure of more than a year on low Earth orbit (LEO). Two experiments were conducted in which cobalt-60 was utilized as the source of radiation. Freely supported piezoelectric sensors were exposed to increasing levels of gamma radiation. Impedance data were collected for the sensors after each radiation exposure. The results show that piezoelectric ceramic material is affected by gamma radiation. Over the course of increasing exposure levels to cobalt-60, the impedance frequencies of the free sensors increased with each absorbed dose. The authors propose that the mechanism causing these impedance changes is due to gamma rays affecting piezoelectric, electric, and elastic constants of the piezoelectric ceramic. A theoretical model describing observed effects is presented.

Electromechanical Impedance Modeling for Structural Health Monitoring

2012 ◽  
Author(s):  
Liuxian Zhao ◽  
Lingyu Yu ◽  
Mattieu Gresil ◽  
Michael Sutton ◽  
Siming Guo
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Electrical Impedance ◽  
Piezoelectric Materials ◽  
Fiber Composite ◽  
Mechanical Impedance ◽  
Experimental Result ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Aluminum Beam

Electromechanical impedance (EMI) method is an effective and powerful technique in structural health monitoring (SHM) which couples the mechanical impedance of host structure with the electrical impedance measured at the piezoelectric wafer active sensor (PWAS) transducer terminals. Due to the electromechanical coupling in piezoelectric materials, changes in structural mechanical impedance are reflected in the electrical impedance measured at the PWAS. Therefore, the structural mechanical resonances are reflected in a virtually identical spectrum of peaks and valleys in the real part of the measured EMI. Multi-physics based finite element method (MP-FEM) has been widely used for the analysis of piezoelectric materials and structures. It uses finite elements taking both electrical and mechanical DOF’s into consideration, which allows good differentiation of complicated structural geometries and damaged areas. In this paper, MP-FEM was then used to simulate PWAS EMI for the goal of SHM. EMI of free PWAS was first simulated and compared with experimental result. Then the constrained PWAS was studied. EMI of both metallic and glass fiber composite materials were simulated. The first case is the constrained PWAS on aluminum beam with various dimensions. The second case studies the sensitivity range of the EMI approach for damage detection on aluminum beam using a set of specimens with cracks at different locations. In the third case, structural damping effects were also studied in this paper.. Our results have also shown that the imaginary part of the impedance and admittance can be used for sensor self-diagnosis.

scholarly journals Health Monitoring of Metallic Structures with Electromechanical Impedance and Piezoelectric Sensors

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1268 ◽  
Author(s):  
Zhu ◽  
Wang ◽  
Qing
Keyword(s):  
Health Monitoring ◽  
Metal Matrix ◽  
Mechanical Impedance ◽  
Simple Calculation ◽  
Health Condition ◽  
Piezoelectric Sensors ◽  
Mean Square ◽  
Metallic Structures ◽  
Electromechanical Impedance ◽  
Aluminum Plates

In order to monitor the health condition of structures in a more sensitive and accurate way, a novel and universal methodology called direct coupling mechanical impedance (DCMI) for characteristic signatures extraction is presented in this paper. This methodology is used to obtain DCMI signatures from measured raw signatures (RSs) with the surface-bonded piezoelectric sensors (PZT), which is developed from a pertinent electromechanical impedance (EMI) theoretical model for surface-bonded circular PZT. The proposed DCMI methodology has the advantages of simple calculation and magnifying the signatures when compared with the existing methods. Combining the extracted DCMI signatures with the root mean square deviation (RMSD) index is able to quantify the correlation between the health condition and the signatures variation more effectively. To verify the effectiveness of proposed DCMI methodology, experiments are conducted on aluminum plates and a part of fuselage in detail. The experimental results sufficiently demonstrate that the presented universal DCMI methodology possesses better sensitivity than the raw signatures when utilized for evaluating the health condition of metallic structures, including those made of metal-matrix nanomaterials.

Implementation and Testing of Smart Composite Laminates with Embedded Piezoelectric Sensors/Actuators

2008 ◽  
Vol 587-588 ◽  
pp. 645-649 ◽  
Author(s):  
Carlos A. Ramos ◽  
Rui de Oliveira ◽  
António Torres Marques
Keyword(s):  
Health Monitoring ◽  
Composite Laminates ◽  
Composite Plate ◽  
Piezoelectric Ceramic ◽  
Piezoelectric Sensors ◽  
Smart Composite ◽  
Dynamic Tests ◽  
Sensing Element ◽  
Three Point Bending ◽  
Piezoelectric Elements

In this study the embedding of piezoelectric ceramics in carbon-fibre/epoxy laminates is studied with the purpose to be used for structural health monitoring from vibration measurements. Piezoelectric elements were embedded in two laminate types made of two weaved prepregs and with four additional unidirectional prepregs, respectively. The efficiency of the embedding process was analysed from the capability of the piezoelectric ceramic to transmit vibrations to the composite plate. The sensing element was successfully used to monitor the composite plate when submitted to three-point bending dynamic tests at different frequencies.

scholarly journals The Effect of Low Earth Orbit Atomic Oxygen Exposure on Phenylphosphine Oxide-Containing Polymers

2000 ◽  
Vol 12 (1) ◽  
pp. 43-52 ◽  
Author(s):  
John W Connell
Keyword(s):  
Thin Film ◽  
Atomic Oxygen ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Earth Orbit ◽  
Cooperative Effort ◽  
Flight Experiment ◽  
Oxygen Exposure ◽  
Atomic Oxygen Exposure ◽  
Phenylphosphine Oxide

Thin films of phenylphosphine oxide-containing polymers were exposed to low Earth orbit aboard a space shuttle flight (STS-85) as part of flight experiment designated Evaluation of Space Environment and Effects on Materials (ESEM). This flight experiment was a cooperative effort between the NASA Langley Research Center (LaRC) and the National Space Development Agency of Japan (NASDA). The thin-film samples described herein were part of an atomic oxygen exposure (AOE) experiment and were exposed to primarily atomic oxygen (∼1×1019 atoms cm−2). The thin-film samples consisted of three phosphine oxide-containing polymers (arylene ether, benzimidazole and imide). Based on post-flight analyses using atomic force microscopy, x-ray photo-electron spectroscopy and weight loss data, it was found that the exposure of these materials to atomic oxygen (AO) produces a phosphorus oxide layer on the surface of the samples. Earlier work has shown that this layer provides a barrier towards further attack by AO. Consequently, these materials do not exhibit linear erosion rates which is in contrast with most organic polymers. Qualitatively, the results obtained from these analyses compare favourably with those obtained from samples exposed to AO and/or an oxygen plasma in ground-based exposure experiments. The results of the low Earth orbit AO exposure on these materials will be compared with those of ground-based exposure to AO.

scholarly journals The affect of the space environment on the survival ofHalorubrum chaoviatorandSynechococcus(Nägeli): data from the Space Experiment OSMO on EXPOSE-R

2014 ◽  
Vol 14 (1) ◽  
pp. 123-128 ◽  
Author(s):  
R. L. Mancinelli
Keyword(s):  
Survival Rate ◽  
Uv Radiation ◽  
Molecular Probes ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Dust Particles ◽  
Most Probable Number ◽  
Earth Orbit ◽  
Probable Number ◽  
Space Vacuum

AbstractWe have shown using ESA's Biopan facility flown in Earth orbit that when exposed to the space environment for 2 weeks the survival rate ofSynechococcus(Nägeli), a halophilic cyanobacterium isolated from the evaporitic gypsum–halite crusts that form along the marine intertidal, andHalorubrum chaoviatora member of the Halobacteriaceae isolated from an evaporitic NaCl crystal obtained from a salt evaporation pond, were higher than all other test organisms exceptBacillusspores. These results led to the EXPOSE-R mission to extend and refine these experiments as part of the experimental package for the external platform space exposure facility on the ISS. The experiment was flown in February 2009 and the organisms were exposed to low-Earth orbit for nearly 2 years. Samples were either exposed to solar ultraviolet (UV)-radiation (λ > 110 nm or λ > 200 nm, cosmic radiation (dosage range 225–320 mGy), or kept in darkness shielded from solar UV-radiation. Half of each of the UV-radiation exposed samples and dark samples were exposed to space vacuum and half kept at 105pascals in argon. Duplicate samples were kept in the laboratory to serve as unexposed controls. Ground simulation control experiments were also performed. After retrieval, organism viability was tested using Molecular Probes Live–Dead Bac-Lite stain and by their reproduction capability. Samples kept in the dark, but exposed to space vacuum had a 90 ± 5% survival rate compared to the ground controls. Samples exposed to full UV-radiation for over a year were bleached and although results from Molecular Probes Live–Dead stain suggested ~10% survival, the data indicate that no survival was detected using cell growth and division using the most probable number method. Those samples exposed to attenuated UV-radiation exhibited limited survival. Results from of this study are relevant to understanding adaptation and evolution of life, the future of life beyond earth, the potential for interplanetary transfer of viable microbes via meteorites and dust particles as well as spacecraft, and the physiology of halophiles.

Integration and evaluation of multiple piezo configurations for optimal health monitoring of reinforced concrete structures

2017 ◽  
Vol 28 (19) ◽  
pp. 2717-2736 ◽  
Author(s):  
Naveet Kaur ◽  
Lingfang Li ◽  
Suresh Bhalla ◽  
Yong Xia ◽  
Pinghe Ni ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Health Monitoring ◽  
Concrete Structures ◽  
Mechanical Impedance ◽  
Metal Wire ◽  
Small Range ◽  
Reinforced Concrete Structures ◽  
Complex Behaviour ◽  
Damage Level ◽  
Impedance Technique

Since the last two decades, the electro-mechanical impedance technique has undergone extensive theoretical and experimental transformations coupled with the evolution of newer practical adaptations and variants. Notable among these are the metal wire–based variant, the dual piezo configuration and the embedded configuration, over and above the conventional surface-bonded configuration. Although there is a plethora of electro-mechanical impedance–related research devoted to metallic structures, only a limited number of studies are available for reinforced concrete structures, which are characterized by more complex behaviour and pose multiple problems for the electro-mechanical impedance sensors such as small range and high damping due to heterogeneous constitution. This article presents, for the first time, a comprehensive comparative study covering four different variants, namely, the surface-bonded single piezo configuration, the embedded single piezo configuration and the metal wire single piezo configuration in electro-mechanical impedance technique for structural health monitoring of a real-life-sized reinforced concrete beam subjected to destructive testing. The article also proposes a modified and more practical version of the dual piezo configuration called the modified dual piezo configuration, employing concrete vibration sensors. It is found that the modified dual piezo configuration is the most expedient among all variants in capturing the damage with respect to the first occurrence of cracks and the final warning of ultimate failure. Metal wire single piezo configuration is good in detecting the first level of damage; however, its efficiency ceases thereafter when crack size increases. It can be considered as an alternative to surface-bonded single piezo configuration in the scenarios where the damage level is incipient. The sensitivity of the modified dual piezo configuration increases with increasing number of actuators connected in parallel due to an increase in the output current. Also, contrary to the surface-bonded single piezo configuration, the susceptance signature of the modified dual piezo configuration is equally sensitive to damage due to the absence of capacitance part in its admittance signature. Hence, its susceptance can also be used for damage severity measurement for incipient damage level in reinforced concrete structures. The surface-bonded single piezo configuration is found to be best in quantifying damage severity in terms of the equivalent stiffness parameter. Embedded single piezo configuration and metal wire single piezo configuration, on the other hand, correlate well with the global dynamic stiffness of the structure. Overall, the proposed integration enables an early detection of damage, its propagation and improved severity measurement for reinforced concrete structures, thus contributing to new application protocols.

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