Characterization of satellite components assembly for responsive space applications

Advancements in fiber-reinforced polymer composite materials damage detection methods: Towards achieving energy-efficient SHM systems

Corrosion characterisation of coated steel involves various approaches via Non- destructive Testing (NDT) and Structural Health Monitoring (SHM) techniques. This paper evaluates and discusses the application of the recent development of a portable lamp-pulsed thickness tester and Commercial Off-the-Shelf (COTS) ultra-high frequency (UHF) radio frequency identification (RFID) sensing. The findings affirm the efficacy of the portable lamp-pulsed thickness tester and COTS UHF RFID sensing for corrosion characterization. Furthermore, these methods are compared with other NDT&E and SHM techniques such as pulsed eddy current (PEC), eddy current pulsed thermography (ECPT), low frequency (LF) RFID, and chipless RFID sensing and monitoring. This study compares the principles, merits, limitations, and accuracy of different corrosion characterization approaches and discusses their future development.

Traditional structural health monitoring (SHM) techniques based on lamb waves are greatly limited in the industrial applications in freeform structures due to the unreconfigurable rigid piezoelectric sensors. Here we have proposed an approach based on flexible macro-fiber composite (MFC) sensors for precise damage location in freeform aluminum plate benefitting from the flexibility and durability of the MFC. Due to the unidirectional behavior of MFC transducer, the receiver with rosette arrangement is introduced to determine the direction of the lamb waves. Thus, the damage, illuminated by the lamb waves actuated by MFC transducers, can be located accurately by two MFC rosettes. Our preliminary results validate the effectiveness and applicability of the proposed detection approach, which opens a new avenue toward the SHM techniques on the complex structures.

Machines without vibrations in the working environment are something non-existent. During machining operations, these vibrations are directly linked to problems in systems having rotating or reciprocating parts, such as bearings, engines, gear boxes, shafts, turbines and motors. Vibration analysis has proved to be a measure for any cause of inaccuracy in manufacturing processes and components or any maintenance decisions related to the machine. The non-contact measurement of vibration signal is very important for reliable structural health monitoring for quality assurance, optimizing profitability of products and services, to enhance manufacturing productivity and to reduce regular periodic inspections. This paper presents a state-of-the-art review of recent vibration monitoring methods and signal processing techniques for structural health monitoring in manufacturing operations. These methods and techniques are used as a tool to acquire, visualize and analyse the sampled data collected in any machining operation which can then be used for decision making about maintenance strategies.

This paper presents the quasi-static thermo-mechanical loading effects on the progressive damage mechanisms and failure modes of the single-bolt, single-shear, hybrid metal-composite, bolted joints in aerospace applications. A three-dimensional finite element method (FEM) technique was used to model the countersunk head bolted joint in details, including geometric and frictional based contact full nonlinearities and using commercial software PATRAN as pre/post-processor. The progressive damage analysis (PDA) in laminated (CFRP/ vinyl ester epoxy) composite material including nonlinear shear behavior, Hashin-type failure criteria and strain-based continuous degradation rules for different values of temperatures was made using SOL 400 NASTRAN solver. In order to validate the numerical results and close investigation of the fracture mechanisms for metal-composite bolted joints by determining ultimate failure loads, experiments were conducted in temperature controlled chamber using SHM (Structural Health Monitoring) technique. The results show that the thermal effects are not negligible on failure mechanism in hybrid aluminum-CFRP bolted joints having strong different thermal expansion coefficients. The complex 3D FEM model using advanced linear continuum solid-shell elements proved computational efficiency and ability to accurately predict the various failure modes as bearing and shear-shear out, including the temperature effects on the failure propagation and damage mechanism of hybrid metal-composite bolted joints.

Radar is a technique commonly used to determine the instantaneous distance between moving objects. This paper proposes the application of a frequency-modulated continuous wave technique for the purpose of drift sensing in a structural health monitoring context. This context requires the measurement of interstorey drift ratios to determine the damage to a structure. Any structural health monitoring system must be able to detect interstorey displacement accurately enough to ensure that any potentially damaging events are detected. The primary motivation for the development of this technique is to negate the limitations of current drift sensing methods (such as accelerometers and line-scan cameras). The proposed system is simulated, and it is found that with sufficiently large frequency sweep bandwidth, errors in displacement tracking can be as low as 0.26% of the actual displacement, with a minimum detectable displacement of 0.1%. These results justify the further development of a hardware prototype.

<p> Although Structural Health Monitoring (SHM) techniques can be considered relatively mature, at least from the scientific point of view, they have not yet become a standard practice in civil engineering because of several reasons. One of these reasons has been individuated in the lack of comprehensive standards addressing the complete SHM process and especially potential utilization. The paper is aimed at briefly reviewing existing standards and tracing the lines for possible extensions, based on experiences gathered from the field and the actual evolution of SHM techniques. Lifecycle approaches including SHM are considered as well. In addition, the relationships between Structural Health Monitoring and Design Standards are addressed, raising the question whether in the design of a monitored structure and of a traditional one, the same safety coefficient should be applied. Consideration is given to the aspect of uncertainty modelling in both cases.</p>

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.

In recent years, data mining technology has been employed to solve various Structural Health Monitoring (SHM) problems as a comprehensive strategy because of its computational capability. Optimization is one the most important functions in Data mining. In an engineering optimization problem, it is not easy to find an exact solution. In this regard, evolutionary techniques have been applied as a part of procedure of achieving the exact solution. Therefore, various metaheuristic algorithms have been developed to solve a variety of engineering optimization problems in SHM. This study presents the most applicable as well as effective evolutionary techniques used in structural damage identification. To this end, a brief overview of metaheuristic techniques is discussed in this paper. Then the most applicable optimization-based algorithms in structural damage identification are presented, i.e. Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Imperialist Competitive Algorithm (ICA) and Ant Colony Optimization (ACO). Some related examples are also detailed in order to indicate the efficiency of these algorithms.

Carbon fiber reinforced polymer materials are widely applied in structure strengthened engineering because of the many advantages of carbon fiber reinforced polymer. However, the debonding damage between the carbon fiber reinforced polymer and host structures occurs frequently, which might lead to the brittle failure of structure components, especially flexural ones. In this paper, an electromechanical impedance-based method, an important technique in structural health monitoring, was adopted to detect the debonding damage of carbon fiber reinforced polymer plate-strengthened steel beam by using lead zirconate titanate (PZT) transducers. A carbon fiber reinforced polymer plate-strengthened steel beam specimen was fabricated in the laboratory and two PZT sensors were attached at different locations on the carbon fiber reinforced polymer plate. The impedance signatures with variation of the different degrees of the debonding damage were measured by an impedance analyzer. The root-mean-square deviation method and the cross-correlation coefficient method were used to quantify the correlation between the electromechanical impedance and the debonding damage degree. The results reflect that an electromechanical impedance-based structural health monitoring technique can serve as a good method to detect the debonding damage of carbon fiber reinforced polymer plate-strengthened steel structures.

first_page settings Order Article Reprints Font Type: Arial Georgia Verdana Font Size: Aa Aa Aa Line Spacing:    Column Width:    Background: Open AccessAbstract Structural Health Monitoring Using Carbon Nanotube Yarns: Sensing Concept and Applications in Composites † by Jandro L. Abot Department of Mechanical Engineering, The Catholic University of America, Washington, DC 20064, USA † Presented at the 5th International Symposium on Sensor Science (I3S 2017), Barcelona, Spain, 27–29 September 2017. Proceedings 2017, 1(8), 852; https://doi.org/10.3390/proceedings1080852 Published: 4 December 2017 (This article belongs to the Proceedings of Proceedings of the 5th International Symposium on Sensor Science (I3S 2017)) Download Download PDF Download PDF with Cover Download XML Versions Notes Non-destructive evaluation and structural health monitoring techniques can provide frequent or immediate feedback of the condition of a structure including potential damage. However, these techniques cannot detect initiating damage in composite materials with high compaction or multifaceted construction. More critically, they are unable to achieve damage detection without altering the microstructure of the composite material. An alternative method of strain monitoring and damage detection that may offer the advantages of structural health monitoring without their drawbacks consists of using piezoresistive-based carbon nanotube (CNT) yarns integrated in polymers and composite materials. The concept is that the CNT yarns form a continuous sensor circuit and their inherent piezoresistive sensitivity detects strain within the host material through resistance measurements without adding much weight or altering the integrity of the host material. This presentation includes a summary of the piezoresistive response of CNT yarns and the concept and latest experimental results on damage detection in laminated polymeric composite materials and distributed and localized strain measurement. Experimental results also show the ability of a combination of different yarn sensors to detect the exact location and extent of delamination in real time. CNT yarn sensors may provide an adaptive, practical, and sensitive structural health monitoring technique. © 2017 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Share and Cite MDPI and ACS Style Abot, J.L. Structural Health Monitoring Using Carbon Nanotube Yarns: Sensing Concept and Applications in Composites. Proceedings 2017, 1, 852. https://doi.org/10.3390/proceedings1080852 AMA Style Abot JL. Structural Health Monitoring Using Carbon Nanotube Yarns: Sensing Concept and Applications in Composites. Proceedings. 2017; 1(8):852. https://doi.org/10.3390/proceedings1080852 Chicago/Turabian Style Abot, Jandro L. 2017. "Structural Health Monitoring Using Carbon Nanotube Yarns: Sensing Concept and Applications in Composites" Proceedings 1, no. 8: 852. https://doi.org/10.3390/proceedings1080852 Find Other Styles Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here. Article Metrics No No Article Access Statistics Multiple requests from the same IP address are counted as one view.

Despite various successful applications of Lead Zirconate Titanate (PZT) transducers in the electromechanical impedance (EMI) technique for structural health monitoring (SHM), fundamental research work on the sensitivity of the PZT transducers for damage detection is still in need. Conventionally, the root mean square deviation (RMSD) is utilized to statistically analyze the differences between the pre-damage and the post-damage electromechanical admittance signatures of a PZT transducer. Recently, another damage index method based on the structural impedance has been derived and successfully used for structural damage diagnosis. This paper presents a comparison of the sensitivity of these two methods to the damages in a concrete structure. An experimental test is carried out on a two-storey concrete frame subjected to base vibrations that simulate the earthquake and underground explosions. A number of PZT transducers are regularly arrayed and bonded to the concrete frame structure. After each phase of vibration loading, the PZT transducers are scanned to acquire the raw signatures of the PZT admittance. Subsequently, the damage indices based on both the raw signatures and the structural impedance extracted from the raw signatures are calculated. Results show that the PZT transducers with different distances away from the damage have different sensitivity to the structural damage. The relation between the damage index and the distance of the PZT transducer away from the damage is studied. Consequently, the sensitivity of the PZT transducers is discussed, and their sensing region in concrete is derived.

High‐frequency structural analysis so far has been a major issue in dynamic analysis, for which many conventional methods such as finite element method and transfer matrix method are unable to perform well. Since the electromechanical impedance technique for structural health monitoring (SHM) operates at very high frequencies, the reverberation matrix method (RMM), which was just developed a few years ago, is employed to study dynamics of the monitored structures, which are bonded with piezoelectric lead zirconate titanate (PZT) patches. A piecewisely homogeneous Euler–Bernoulli beam model is introduced to approximate the non‐homogeneous beam and only one‐dimensional axial vibration of PZT wafers is considered. The imperfect interfacial bonding between PZT patches and the host beam is investigated based on a shear lag model. Using a hybrid technique combining electromechanical impedance method and RMM, an analytical expression of impedance (or admittance) related to the response of the coupled model of PZT patch‐bonding layer‐host beam system is derived for SHM. The proposed method is examined by comparing with other theoretical methods as well as by means of a test on an intelligent system using a steel beam with two symmetrically installed PZT wafers. It could be further applied to predicting the dynamics of monitored Timoshenko beams, continuous beams, and framed structures as well. Copyright © 2006 John Wiley & Sons, Ltd.

The aim of the present paper is to evaluate structural health monitoring (SHM) techniques based on modal analysis for crack detection in small wind turbine blades. A finite element (FE) model calibrated to measured modal parameters will be introduced to cracks with different sizes along one edge of the blade. Changes in modal parameters from the FE model are compared with data obtained from experimental tests. These comparisons will be used to validate the FE model and subsequently discuss the usability of SHM techniques based on modal parameters for condition monitoring of wind turbine blades.

This paper investigates a Structural Health Monitoring (SHM) technique for the detection of accidental disbonds of stiffeners in fuselage panels. The method relies on the perturbation introduced by disbonded areas in the propagation of flexural Lamb waves emitted by a piezoelectric PZT (Lead Zirconate Titanate) disc. A quantitative threshold based on the energy of captured signals is proposed for detection. Both PZT discs and Fiber Bragg Gratings (FBG) are studied as potential receiver sensors for signal collection. Finally, the possibility of using Laser Doppler Vibrometer (LDV) data to evaluate the sensitivity of the method for a particular sensor position, and excitation frequency is emphasized and discussed. doi: 10.12783/SHM2015/12