Finite Element Modeling of Spiral Frequency Steerable Acoustic Transducers (FSATs) for guided waves based Structural Health Monitoring of plate-like structures

Structural Health Monitoring (SHM) is an emerging area of research associated to improvement of maintainability and the safety of aerospace, civil and mechanical infrastructures by means of monitoring and damage detection. Guided wave structural testing method is an approach for health monitoring of plate-like structures using smart material piezoelectric transducers. Among many kinds of transducers, the ones that have beam steering feature can perform more accurate surface interrogation. A frequency steerable acoustic transducer (FSATs) is capable of beam steering by varying the input frequency and consequently can detect and localize damage in structures. Guided wave inspection is typically performed through phased arrays which feature a large number of piezoelectric transducers, complexity and limitations. To overcome the weight penalty, the complex circuity and maintenance concern associated with wiring a large number of transducers, new FSATs are proposed that present inherent directional capabilities when generating and sensing elastic waves. The first generation of Spiral FSAT has two main limitations. First, waves are excited or sensed in one direction and in the opposite one (180 ̊ ambiguity) and second, just a relatively rude approximation of the desired directivity has been attained. Second generation of Spiral FSAT is proposed to overcome the first generation limitations. The importance of simulation tools becomes higher when a new idea is proposed and starts to be developed. The shaped transducer concept, especially the second generation of spiral FSAT is a novel idea in guided waves based of Structural Health Monitoring systems, hence finding a simulation tool is a necessity to develop various design aspects of this innovative transducer. In this work, the numerical simulation of the 1st and 2nd generations of Spiral FSAT has been conducted to prove the directional capability of excited guided waves through a plate-like structure.

Monitoraggio strutturale (structural health monitoring) di laminati CFRP tramite reticoli di Bragg in fibra ottica

Lo studio si propone di valutare la capacità dei reticoli di Bragg in fibra ottica, di individuare e monitorare danneggiamenti presenti all'interno di laminati in composito, tramite l'analisi degli spettri riflessi dai reticoli stessi. Sono stati utilizzati due tipi diversi di stratificazione dei laminati, per valutare il diverso comportamento dei reticoli di Bragg inseriti all'interno dei laminati. Le proprietà dei materiali e degli spettri riflessi dai reticoli, sono state messe in relazione qualitativamente e quantitativamente, al fine di sviluppare un valido metodo di Structural Health Monitoring.

Structural health of a road tunnel intersecting a large and active rockslide

This work presents the case of the San Lorenzo road tunnel, a transportation infrastructure located in the northern part of Italy, involved in the so-called Passo della Morte landslide. This tunnel crosses a large rockslide characterized by slow movements. Damages like water seepage inside the tunnel and concrete lining detachments have surfaced through the years, increasing the risk. This work develops the objective of tracing back the landslide-induced stresses directly responsible for the cracks’ pattern on the most damaged segments of the tunnel. The first section of this work gives information about the global framework: site geography and its strategic relevance, geological setting, hydrological and climate conditions will be provided. The road tunnel infrastructure and its interaction with the landslide phenomena will be discussed together with the active monitoring system, which has been working for more than 20 years. In the second part the several steps and tools used to add more details about the road damages are reported. A visualization of the actual state of the most damaged portions of the road has been reached. Then the attention has been addressed to the stresses acting on the road tunnel’s aforesaid portions, developing a FEM model of a section of the tunnel through a selected software. This latter process can be deemed as a beginning for further developments. Some preliminary results are shown to demonstrate the goodness of the assumptions made. The possible future set by this work aims at constant enlargement of information to be provided to the FEM software, and at the validation of the obtained results through the monitoring data interpretative tools.

Substructuring approache in state space models for dynamic system parameters identification

In the recent decade, the request for structural health monitoring expertise increased exponentially in the United States. The aging issues that most of the transportation structures are experiencing can put in serious jeopardy the economic system of a region as well as of a country. At the same time, the monitoring of structures is a central topic of discussion in Europe, where the preservation of historical buildings has been addressed over the last four centuries. More recently, various concerns arose about security performance of civil structures after tragic events such the 9/11 or the 2011 Japan earthquake: engineers looks for a design able to resist exceptional loadings due to earthquakes, hurricanes and terrorist attacks. After events of such a kind, the assessment of the remaining life of the structure is at least as important as the initial performance design. Consequently, it appears very clear that the introduction of reliable and accessible damage assessment techniques is crucial for the localization of issues and for a correct and immediate rehabilitation. The System Identification is a branch of the more general Control Theory. In Civil Engineering, this field addresses the techniques needed to find mechanical characteristics as the stiffness or the mass starting from the signals captured by sensors. The objective of the Dynamic Structural Identification (DSI) is to define, starting from experimental measurements, the modal fundamental parameters of a generic structure in order to characterize, via a mathematical model, the dynamic behavior. The knowledge of these parameters is helpful in the Model Updating procedure, that permits to define corrected theoretical models through experimental validation. The main aim of this technique is to minimize the differences between the theoretical model results and in situ measurements of dynamic data. Therefore, the new model becomes a very effective control practice when it comes to rehabilitation of structures or damage assessment. The instrumentation of a whole structure is an unfeasible procedure sometimes because of the high cost involved or, sometimes, because it’s not possible to physically reach each point of the structure. Therefore, numerous scholars have been trying to address this problem. In general two are the main involved methods. Since the limited number of sensors, in a first case, it’s possible to gather time histories only for some locations, then to move the instruments to another location and replay the procedure. Otherwise, if the number of sensors is enough and the structure does not present a complicate geometry, it’s usually sufficient to detect only the principal first modes. This two problems are well presented in the works of Balsamo [1] for the application to a simple system and Jun [2] for the analysis of system with a limited number of sensors. Once the system identification has been carried, it is possible to access the actual system characteristics. A frequent practice is to create an updated FEM model and assess whether the structure fulfills or not the requested functions. Once again the objective of this work is to present a general methodology to analyze big structure using a limited number of instrumentation and at the same time, obtaining the most information about an identified structure without recalling methodologies of difficult interpretation. A general framework of the state space identification procedure via OKID/ERA algorithm is developed and implemented in Matlab. Then, some simple examples are proposed to highlight the principal characteristics and advantage of this methodology. A new algebraic manipulation for a prolific use of substructuring results is developed and implemented.

Deep Learning Architectures for time of arrival detection in Acoustic Emissions Monitoring

Acoustic Emission (AE) monitoring can be used to detect the presence of damage as well as determine its location in Structural Health Monitoring (SHM) applications. Information on the time difference of the signal generated by the damage event arriving at different sensors is essential in performing localization. This makes the time of arrival (ToA) an important piece of information to retrieve from the AE signal. Generally, this is determined using statistical methods such as the Akaike Information Criterion (AIC) which is particularly prone to errors in the presence of noise. And given that the structures of interest are surrounded with harsh environments, a way to accurately estimate the arrival time in such noisy scenarios is of particular interest. In this work, two new methods are presented to estimate the arrival times of AE signals which are based on Machine Learning. Inspired by great results in the field, two models are presented which are Deep Learning models - a subset of machine learning. They are based on Convolutional Neural Network (CNN) and Capsule Neural Network (CapsNet). The primary advantage of such models is that they do not require the user to pre-define selected features but only require raw data to be given and the models establish non-linear relationships between the inputs and outputs. The performance of the models is evaluated using AE signals generated by a custom ray-tracing algorithm by propagating them on an aluminium plate and compared to AIC. It was found that the relative error in estimation on the test set was < 5% for the models compared to around 45% of AIC. The testing process was further continued by preparing an experimental setup and acquiring real AE signals to test on. Similar performances were observed where the two models not only outperform AIC by more than a magnitude in their average errors but also they were shown to be a lot more robust as compared to AIC which fails in the presence of noise.

Machine Learning Unsupervised Methods in the Design of an On-board Health Monitoring System for Satellite Applications

The dissertation starts by providing a description of the phenomena related to the increasing importance recently acquired by satellite applications. The spread of such technology comes with implications, such as an increase in maintenance cost, from which derives the interest in developing advanced techniques that favor an augmented autonomy of spacecrafts in health monitoring. Machine learning techniques are widely employed to lay a foundation for effective systems specialized in fault detection by examining telemetry data. Telemetry consists of a considerable amount of information; therefore, the adopted algorithms must be able to handle multivariate data while facing the limitations imposed by on-board hardware features. In the framework of outlier detection, the dissertation addresses the topic of unsupervised machine learning methods. In the unsupervised scenario, lack of prior knowledge of the data behavior is assumed. In the specific, two models are brought to attention, namely Local Outlier Factor and One-Class Support Vector Machines. Their performances are compared in terms of both the achieved prediction accuracy and the equivalent computational cost. Both models are trained and tested upon the same sets of time series data in a variety of settings, finalized at gaining insights on the effect of the increase in dimensionality. The obtained results allow to claim that both models, combined with a proper tuning of their characteristic parameters, successfully comply with the role of outlier detectors in multivariate time series data. Nevertheless, under this specific context, Local Outlier Factor results to be outperforming One-Class SVM, in that it proves to be more stable over a wider range of input parameter values. This property is especially valuable in unsupervised learning since it suggests that the model is keen to adapting to unforeseen patterns.

Smart structures: sperimentazione mediante attuatori e sensori innovativi

L’idea di base della seguente tesi, finora mai applicata o descritta in letteratura scientifica in base alle ricerche effettuate, è stata quella di creare un sistema di monitoraggio strutturale intelligente (Structural Health Monitoring, SHM) mediante dei sensori di deformazione a reticolo di Bragg (Fiber Bragg Grating, FBG), incollati su fili a memoria di forma inseriti a loro volta, bloccati con opportuni ancoraggi esterni, in sei travi di betoncino cementizio armato. L’obbiettivo della sperimentazione è stato quindi quello di creare delle travi intelligenti che, in condizioni di carico eccezionali e critiche (monitorate dal sensore a fibra ottica), sapessero “autoripararsi” mediante gli attuatori a memoria di forma con un processo di riscaldamento appositamente progettato.

Processing of measured acceleration response for SHM purpose

Structural Health Monitoring (SHM) is the process of characterization for existing civil structures that proposes for damage detection and structural identification. It's based firstly on the collection of data that are inevitably affected by noise. In this work a procedure to denoise the measured acceleration signal is proposed, based on EMD-thresholding techniques. Moreover the velocity and displacement responses are estimated, starting from measured acceleration.

Valutazione analitica delle aree di delaminazione in materiali compositi avanzati soggetti ad impatti a bassa velocità

In questo lavoro di tesi è stato elaborato un modello analitico al fine di ottenere una stima dell’ampiezza di delaminazione a seguito di impatti a bassa velocità in laminati in composito, in particolare carbon/epoxy. Nel capitolo 2 è descritto il comportamento meccanico di tali laminati (equazioni costitutive della singola lamina, dell’intero laminato e costanti ingegneristiche dell’intero laminato per qualsiasi sistema di riferimento). Nel capitolo 3 viene descritta la filosofia di progettazione damage tolerance per tali materiali sottoposti a low-velocity impact (LVI) e richiamato il concetto di structural health monitoring. In particolare vengono descritti i tipi di difetti per un laminato in composito, vengono classificati gli impatti trasversali e si rivolge particolare attenzione agli impatti a bassa velocità. Nel paragrafo 3.4 sono invece elencate diverse tecniche di ispezione, distruttive e non, con particolare attenzione alla loro applicazione ai laminati in composito. Nel capitolo 4 è riportato lo stato dell’arte per la stima e la predizione dei danni dovuti a LVI nei laminati: vengono mostrate alcune tecniche che permettono di stimare accuratamente l’inizio del danno, la profondità dell’indentazione, la rottura delle fibre di rinforzo e la forza massima di impatto. L’estensione della delaminazione invece, è difficile da stimare a causa dei numerosi fattori che influenzano la risposta agli impatti: spesso vengono utilizzati, per tale stima, modelli numerici piuttosto dispendiosi in termini di tempo e di calcolo computazionale. Nel capitolo 5 viene quindi mostrata una prima formula analitica per il calcolo della delaminazione, risultata però inaffidabile perché tiene conto di un numero decisamente ristretto di fattori che influenzano il comportamento agli LVI. Nel capitolo 6 è mostrato un secondo metodo analitico in grado di calcolare l’ampiezza di delaminazione mediante un continuo aggiornamento della deflessione del laminato. Dal confronto con numerose prove sperimentali, sembra che il modello fornisca risultati vicini al comportamento reale. Il modello è inoltre fortemente sensibile al valore della G_IIc relativa alla resina, alle dimensioni del laminato e alle condizioni di vincolo. É invece poco sensibile alle variazioni delle costanti ingegneristiche e alla sequenza delle lamine che costituiscono il laminato. La differenza tra i risultati sperimentali e i risultati del modello analitico è influenzata da molteplici fattori, tra cui il più significativo sembra essere il valore della rigidezza flessionale, assunto costante dal modello.

Campionamento e ricostruzione di immagini full wavefield per il monitoraggio strutturale

L'elaborato affronta la definizione di differenti strategie per il campionamento e la ricostruzione di segnali wavefield per applicazioni di monitoraggio strutturale. In accordo con quanto indicato dalla teoria del Compressive Sensing, obiettivo della tesi è la minimizzazione del numero di punti di acquisizione al fine di ridurre lo sforzo energetico del campionamento. I risultati sono validati in ambiente Matlab utilizzando come riferimento segnali acquisiti su setup sperimentali in alluminio o materiale composito in presenza di diverse tipologie di difetto.

Applicazione di reticoli di Bragg "chirped" per il monitoraggio strutturale di laminati CFRP

L’uso dei materiali compositi è andato aumentando negli ultimi decenni per la loro elevata rigidezza, la resistenza specifica e il possibile risparmio, notevole in termini di peso dell’intera struttura. Tali materiali introducono però nuove problematiche riguardanti le modalità di danneggiamento e il comportamento a fatica. Mentre questi fenomeni sono relativamente ben compresi nei materiali metallici, per una struttura in composito non esistono ancora modelli in grado di predire con sufficiente affidabilità l’evoluzione del danneggiamento. Negli ultimi anni la ricerca si è focalizzata sullo sviluppo di sistemi in grado di rilevare la presenza e l’evoluzione del danno, definiti Structural Health Monitoring Systems, ovvero sistemi di monitoraggio strutturale. Il danneggiamento strutturale può così essere individuato e identificato per mezzo di sensori distribuiti integrati nella struttura stessa, aventi la possibilità di trasmettere queste informazioni a un sistema di analisi esterno permettendo di valutare lo stato di degrado della struttura in tempo reale. In questo contesto si inseriscono le attività di ricerca sulle strutture intelligenti che, inglobando al loro interno opportune tipologie di sensori e attuatori, sono in grado di monitorare l’ambiente fisico operativo, raccoglierne e interpretarne le informazioni per poi rispondere ai cambiamenti della struttura in modo appropriato attraverso gli attuatori. L’impiego di sensori e attuatori inglobati nelle strutture offre molteplici vantaggi rispetto ai sistemi di trasduzione e attuazione convenzionali. L’attività di ricerca condotta in questa tesi è rivolta all’indagine di tecniche di SHM per mezzo di sensori a fibra ottica. Essi presentano molteplici peculiarità che li rendono i candidati ideali per queste applicazioni. Esistono diversi tipi di sensori che utilizzano le fibre ottiche. Nel presente lavoro si sono utilizzati sensori di deformazione basati sui reticoli di Bragg (FBG) chirped. Questi sensori sono costituiti da un reticolo inscritto all’interno della fibra, che ha l’effetto di riflettere solo alcune lunghezze d’onda della luce incidente. Se le proprietà geometriche del reticolo cambiano per effetto di una deformazione, cambia anche la forma dello spettro riflesso. Inoltre, con il tipo di sensore usato, è possibile correlare lo spettro con la posizione di eventuali danneggiamenti interni al materiale. Gli obbiettivi di questa ricerca sono di verificare gli effetti della presenza di una fibra ottica sulle caratteristiche meccaniche di un laminato e di trovare un legame tra la risposta in frequenza del sensore FBG e lo stato tensionale e il grado di danneggiamento di un componente in composito.

Studio di un sistema di comunicazione ad alimentazione risonante wireless.

L'elaborato tratta della progettazione di un sistema di alimentazione wireless risonante per i nodi sensori, strumenti fondamentali per il controllo delle strutture(Structural Health Monitoring). Esso si concentra sulla realizzazione di un convertitore flyback risonante (con circuito di snubber incluso per il main switch) in grado di fornire una tensione di 5 Volt in uscita a fronte di una corrente media massima sul carico di 800mA data una tensione di 12 volt in ingresso. Dopo aver introdotto il concetto di Wireless Power Transfer (WPT) e i principi fisici su cui esso poggia (induzione elettromagnetica e risonanza elettromagnetica), si presentano i modelli circuitali più utilizzati in questo ambito. Una volta illustrate le conoscenze allo stato dell'arte dell'accoppiamento induttivo risonante, si analizza il comportamento del modello scelto, al fine di evidenziare i vantaggi dell'utilizzo del circuito alla frequenza di risonanza. Sono state effettuate simulazioni con il simulatore LTspice come controprova. Si passa quindi a dimensionare i vari elementi del circuito a fronte delle specifiche stabilite. Grazie ai risultati ottenuti, si procede alla stesura del Bill Of Materials. La tesi si conclude presentando i possibili campi di ricerca e sviluppo del sistema di alimentazione.

Loading and damage modelling for an integrated SHM system of a prestressed concrete railway bridge in Naples

The thesis explores recent technology developments in the field of structural health monitoring and its application to railway bridge projects. It focuses on two main topics. First, service loads and effect of environmental actions are modelled. In particular, the train moving load and its interaction with rail track is considered with different degrees of detail. Hence, results are compared with real-time experimental measurements. Secondly, the work concerns the identification, definition and modelling process of damages for a prestressed concrete railway bridge, and their implementation inside FEM models. Along with a critical interpretation of the in-field measurements, this approach results in the development of undamaged and damaged databases for the AI-aided detection of anomalies and the definition of threshold levels to prompt automatic alert interventions. In conclusion, an innovative solution for the development of the railway weight-in-motion system is proposed.

Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

A new method for continuous quality control of nsm cfrp systems

In the last decade the near-surface mounted (NSM) strengthening technique using carbon fibre reinforced polymers (CFRP) has been increasingly used to improve the load carrying capacity of concrete members. Compared to externally bonded reinforcement (EBR), the NSM system presents considerable advantages. This technique consists in the insertion of carbon fibre reinforced polymer laminate strips into pre-cut slits opened in the concrete cover of the elements to be strengthened. CFRP reinforcement is bonded to concrete with an appropriate groove filler, typically epoxy adhesive or cement grout. Up to now, research efforts have been mainly focused on several structural aspects, such as: bond behaviour, flexural and/or shear strengthening effectiveness, and energy dissipation capacity of beam-column joints. In such research works, as well as in field applications, the most widespread adhesives that are used to bond reinforcements to concrete are epoxy resins. It is largely accepted that the performance of the whole application of NSM systems strongly depends on the mechanical properties of the epoxy resins, for which proper curing conditions must be assured. Therefore, the existence of non-destructive methods that allow monitoring the curing process of epoxy resins in the NSM CFRP system is desirable, in view of obtaining continuous information that can provide indication in regard to the effectiveness of curing and the expectable bond behaviour of CFRP/adhesive/concrete systems. The experimental research was developed at the Laboratory of the Structural Division of the Civil Engineering Department of the University of Minho in Guimar\~aes, Portugal (LEST). The main objective was to develop and propose a new method for continuous quality control of the curing of epoxy resins applied in NSM CFRP strengthening systems. This objective is pursued through the adaptation of an existing technique, termed EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method) that has been developed for monitoring the early stiffness evolution of cement-based materials. The experimental program was composed of two parts: (i) direct pull-out tests on concrete specimens strengthened with NSM CFRP laminate strips were conducted to assess the evolution of bond behaviour between CFRP and concrete since early ages; and, (ii) EMM-ARM tests were carried out for monitoring the progressive stiffness development of the structural adhesive used in CFRP applications. In order to verify the capability of the proposed method for evaluating the elastic modulus of the epoxy, static E-Modulus was determined through tension tests. The results of the two series of tests were then combined and compared to evaluate the possibility of implementation of a new method for the continuous monitoring and quality control of NSM CFRP applications.