Preliminary acousto-ultrasonic investigation for multi-parameter transducer self-diagnostic system in composites

Memmolo, Vittorio; Park, Y.J.; Lilov, Mihail; Monaco, Ernesto; Ricci, Fabrizio

doi:10.1016/j.compstruct.2018.05.125

Cited by 10 publications

(5 citation statements)

References 26 publications

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“…One of the more challenging aspects is the robustness of the methodology versus number of sensors adopted, which may also varying during the system lifetime. Sensors may fail due to the harsh condition that they have to withstand [50,51] and a self diagnosis approach should be integrated together with a health management strategy continuously pursuing the minimum target to achieve the prescribed POD. This means that the effect of missing sensors has to be addressed a priori to continuously predict the minimum detectable damage.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Damage Localization in Composite Structures Using a Guided Waves Based Multi-Parameter Approach

et al. 2018

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Aerospace vehicles are demanded to withstand harsh conditions with a low weight impact. Composites have been increasingly adopted to meet such performances but they are affected by sudden and barely visible failures when subjected to low velocity impacts. The design criteria and the maintenance tasks in a damage tolerant approach are unavoidably compromised. Structural Health Monitoring is expected to avoid typical accommodations employed during design and lifetime management by achieving a cost-effective and on condition maintenance. This paper describes the use of guided ultrasonic waves excited and sensed by permanently attached piezoelectric transducers for detection and localization of unforeseen and hidden flaws in composite structures. A composite stiffened structures designed for real scale components is investigated to test a multi-parameter detection technique capable of predicting different wave features affected by hidden failures to detect any possible change in the structure. Usually, propagation behavior is exploited to detect changes in the waveguide focusing on the analysis of an intrinsic feature of the propagating wave. Numerical simulations and measurements carried out on a real-scale aircraft structure demonstrate that increasing the observed characteristics improves the result making efficient the diagnosis. Furthermore, it is shown that accounting a multi-parameter analysis of ultrasonic data enhances the localization reliability making use of the same reconstruction algorithm with data fusion approach while facing with different kind of damages.

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Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Damage Localization in Composite Structures Using a Guided Waves Based Multi-Parameter Approach

et al. 2018

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“…Both electro-mechanical impedance (EMI) or EMA spectra can evaluate the health as well as bonding condition of a PCT and has been used by many studies as an criterion to evaluate the sensor health and debonding [ 10 , 15 , 34 , 35 ]. However, the imaginary parts of EMI or EMA are predominantly affected by the PCT defects, and especially the imaginary part of the admittance, known as susceptance, is sensitive to the changes in the bond layer [ 15 , 36 ]. The main characteristic of the susceptance spectra (SS) that were used to evaluate the integrity and durability of the AUCTs during the AOEC tests are as follows: The slope of the SS curve obtaining through linear fitting; The change in the resonance characteristics of the SS, i.e., the amplitude and the frequency of the first natural frequency.…”

Section: Experimental Methodsmentioning

confidence: 99%

An Efficient Procedure for Bonding Piezoelectric Transducers to Thermoplastic Composite Structures for SHM Application and Its Durability in Aeronautical Environmental Conditions

Sofi

Gude

Wierach

et al. 2023

Sensors

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Piezoceramic transducers (PCTs) bonded to carbon fiber-reinforced plastic (CFRP) composite structures must be durable as well as remain properly bonded to the structure in order to provide reliable data for accurate guided-wave-based structural health monitoring (SHM) of aeronautical components. The current method of bonding transducers to composite structures through epoxy adhesives faces some shortcomings, such as difficult reparability, lack of weldability, longer curing cycles, and shorter shelf life. To overcome these shortcomings, a new efficient procedure for bonding the transducers to thermoplastic (TP) composite structures was developed by utilizing TP adhesive films. Application-suitable TP films (TPFs) were identified and characterized through standard differential scanning calorimetry (DSC) and single lap shear (SLS) tests to study their melting behavior and bonding strength, respectively. Special PCTs called acousto-ultrasonic composite transducers (AUCTs) were bonded to high-performance TP composites (carbon fiber Poly-Ether-Ether-Ketone) coupons with a reference adhesive (Loctite EA 9695) and the selected TPFs. The integrity and durability of the bonded AUCTs in aeronautical operational environmental conditions (AOEC) were assessed in accordance to the standard Radio Technical Commission for Aeronautics DO-160. The AOEC tests performed were operating low and high temperatures, thermal cycling, hot-wet, and fluid susceptibility tests. The health and bonding quality of the AUCTs were evaluated by the electro-mechanical impedance (EMI) spectroscopy method and ultrasonic inspections. The AUCT defects were created artificially and their influence on the susceptance spectra (SS) was measured to compare them with the AOEC-tested AUCTs. The results show that a small change occurred in the SS characteristics of the bonded AUCTs in all of the adhesive cases after the AOEC tests. After comparing the changes in SS characteristics of simulated defects with that of the AOEC-tested AUCTs, the change is relatively smaller and therefore it can be concluded that no serious degradation of the AUCT or the adhesive layer has occurred. It was observed that the most critical tests among the AOEC tests are the fluid susceptibility tests, which can cause the biggest change in the SS characteristics. Comparing the performance of the AUCTs bonded with the reference adhesive and the selected TPFs in the AOEC tests, it was seen that some of the TPFs, e.g., Pontacol 22.100 outperforms the reference adhesive, while the other TPFs have similar performance to that of the reference adhesive. Therefore, in conclusion, the AUCTs bonded with the selected TPFs can withstand the operational and environmental conditions of an aircraft structure, and hence, the proposed procedure is easily installed, reparable, and a more reliable method of bonding sensors to aircraft structures.

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“…36 Historically, self-diagnostic properties have been induced into composites using PZT transduces onto various points of a composite and examining generated voltage peaks w. r. t structural health status of composite. 37 Bucky paper is a thin membrane like structure consisting of highly entangled carbon nanotubes and having good electromechanical properties, which allow it to change electrical resistance values with induced strain. The use of bucky paper membranes in the interlaminar region of laminated composites is useful in inducing self-diagnostic properties in composites.…”

Section: Introductionmentioning

confidence: 99%

Development of knitted reinforced structures with self-diagnostic function for composite applications

Abbas

Ahmad

Zahid

et al. 2022

Journal of Industrial Textiles

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The research aims the development of knitted reinforcement structures for inducing self-diagnostic properties into knitted reinforced composites for structural health monitoring. Conductive carbon fiber was used in knitted inlaid structures as inlay yarns, and l × 1 Rib knitted base fabric of polyester filament yarn was used for knitting. The reinforcement’s conductive nature induced self-diagnostic properties into composites using correlation of mechanical damages and changes in electrical resistance values. Single and double stimuli layers and inlay patterns of 3 × 1, 6 × 1 and 9 × 1 was used to check their impact on self-diagnostic properties. Mechanical testing and real-time electrical resistance monitoring proved knitted structures as a solution to induce self-diagnostic properties into composite materials. Composites having double stimuli (conductive) layers exhibited better self-diagnostic properties than single stimuli layer composites, and the self-diagnostic properties also improved as the inlay pattern of reinforcement moved from 9 × 1 to 6 × 1 and 3 × 1 inlay. Such knitted reinforced self-diagnostic composites could be practically used in structural health monitoring applications, e.g., complicated structures of large buildings infrastructures and machinery which require record of each minor happening with structures to keep smooth and successful running of the system.

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Preliminary acousto-ultrasonic investigation for multi-parameter transducer self-diagnostic system in composites

Cited by 10 publications

References 26 publications

Damage Localization in Composite Structures Using a Guided Waves Based Multi-Parameter Approach

Damage Localization in Composite Structures Using a Guided Waves Based Multi-Parameter Approach

An Efficient Procedure for Bonding Piezoelectric Transducers to Thermoplastic Composite Structures for SHM Application and Its Durability in Aeronautical Environmental Conditions

Development of knitted reinforced structures with self-diagnostic function for composite applications

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