Prof. Ernesto Monaco Profile

Prof. Ernesto Monaco

Associate professor at Univ. degli Studi di Napoli Federico II

SPIE Involvement:

Conference Program Committee | Author

Publications (26)

Proceedings Article | 10 May 2024 Presentation

Development and testing of graphene nanofilled sensors applied on composite aerospace structural items for structural dynamic and SHM applications

Ernesto Monaco, Fabrizio Ricci, Massimo Viscardi, Pietro Russo

Proceedings Volume 12951, 129511Y (2024) https://doi.org/10.1117/12.3010165

KEYWORDS: Sensors, Structural health monitoring, Graphene, Aerospace engineering, Structural dynamics, Composites, Matrices, Viscosity, Signal to noise ratio, Signal detection

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Proceedings Article | 9 May 2024 Presentation + Paper

Investigation of damages in impacted thick composite panels by NDI methods

Pietro Russo, Veronica Vespini, Sara Coppola, Fabiana Graziano, Pietro Ferraro, Simonetta Grilli, Massimo Rippa, Ettore Stella, Massimiliano Nitti, Vito Renò, Giuseppe Del Prete, Valerio Dentico, Nicola Gallo, Vittorio Memmolo, Ernesto Monaco, Fabrizio Ricci

Proceedings Volume 12947, 1294704 (2024) https://doi.org/10.1117/12.3010125

KEYWORDS: Composites, Nondestructive evaluation, Shearography, Inspection, Defect detection, Statistical analysis, Thermography, Polymers, Laser interferometry, Sensors

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Proceedings Article | 9 May 2024 Poster + Paper

Multimodal NDT inspection and characterization of composite honeycomb sandwich samples with programmed flaws

Veronica Vespini, Sara Coppola, Fabiana Graziano, Simonetta Grilli, Pietro Ferraro, Massimo Rippa, Pietro Russo, Valerio Dentico, Giuseppe Del Prete, Nicola Gallo, Vittorio Memmolo, Ernesto Monaco, Fabrizio Ricci

Proceedings Volume 12951, 129512L (2024) https://doi.org/10.1117/12.3010360

KEYWORDS: Nondestructive evaluation, Composites, Inspection, Defect detection, Statistical analysis, Shearography, Thermography, Laser ultrasonics, Industry, Aerospace engineering

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Proceedings Article | 25 April 2023 Presentation

Development and testing of polyamide 6/graphene nanoplatelets sensors applied on composite plates for structural dynamic and SHM applications (Conference Presentation)

Ernesto Monaco, Pietro Russo, Vittorio Memmolo, Fabrizio Ricci

Proceedings Volume 12488, 124880R (2023) https://doi.org/10.1117/12.2660083

KEYWORDS: Sensors, Structural health monitoring, Composites, Structural dynamics, Graphene, Aerospace engineering, Wave propagation, Ultrasonography, Signal to noise ratio, Polymers

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Proceedings Article | 25 April 2023 Presentation + Paper

Deep learning algorithms for delaminations identification on composite panels by wave propagation signal analysis

E. Monaco, F. Ricci, N. Boffa

Proceedings Volume 12488, 124881D (2023) https://doi.org/10.1117/12.2660094

KEYWORDS: Image classification, Sensors, Neural networks, Wave propagation, Signal detection, Matrices, Deep learning, Composites

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Proceedings Article | 25 April 2023 Presentation + Paper

Changes in the state of ice buildup on a composite plate: ultrasonic monitoring and assessment

L. Maio, V. Memmolo, J. Moll, E. Monaco, F. Ricci

Proceedings Volume 12488, 1248807 (2023) https://doi.org/10.1117/12.2662463

KEYWORDS: Ice, Ultrasonics, Wave propagation, Waveguides, Transducers, Ultrasound transducers, Composites

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Proceedings Article | 22 March 2021 Presentation + Paper

Static behavior of a disbonded stringer in a co-infused stiffened panel

N. Boffa, F. Ricci, E. Monaco, G. Galiano

Proceedings Volume 11593, 115930S (2021) https://doi.org/10.1117/12.2583232

KEYWORDS: Composites, Wave propagation, Fiber optics sensors, Waveguides, Ultrasonography, Structural health monitoring, Sensors, Reliability, Numerical simulations, Nondestructive evaluation

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Structural Health Monitoring deals mainly with sensorized structures where sensors can be secondary bonded on metallic or composite structural elements. Aerospace structural design must account for Damage Tolerance (DT) of structures. To accomplish the airworthiness, a flawed structure is required to stand the design load without any growth and, eventually, repaired. For metallic materials, the damage tolerance approaches are well-established and rely on the evaluation (theoretically and experimentally) of crack propagation velocity. For composite structures the damage-tolerance design is more challenging as the failures that may occur are of different type, most of the times hidden inside the structure and can grow up to a critical size before the conventional inspection techniques detect them. Within the DT approach one of the showstoppers for the full implementation of adhesive bonds in composites (i.e. stringer-skin connections for stiffened plates) are the airworthiness certification requirements for composite aircraft structures as presented within the FAA Advisory Circular 20-107B. In that document the general methods for substantiating the limit load capacity of any bonded stiffener, the failure of which would result in catastrophic loss of the airplane, are prescribed. Among the suggested methods, the only one really permitting to achieve the optimal bonding efficiency without the addiction of disbond stoppers (i.e. rivets), is a “repeatable and reliable non-destructive inspection techniques ensuring the strength of each joint”. That assumption implies the implementation of a reliable SHM system capable of monitoring the extent of an eventual disbond until it reaches a critical dimension at limit load. This paper will present the preliminary results of a research activity where the authors apply static loads to a stiffened plate made of a skin and a bonded stringer (co-infused) where a disbond “starter” has been included during manufacturing. The plate has been sensorized with a strain gauge system to detect the disbonding evolution during load application, in order to verify the effectiveness within a DT approach.

Proceedings Article | 22 March 2021 Presentation + Paper

Simulation of waves propagation into composites thin shells by FEM methodologies for training of deep neural networks aimed at damage reconstruction

E. Monaco, N. Boffa, F. Ricci, M. Rautela, D. Passato, M. Cinque

Proceedings Volume 11593, 1159318 (2021) https://doi.org/10.1117/12.2583572

KEYWORDS: Composites, Wave propagation, Finite element methods, Neural networks, Sensors, Structural health monitoring, Signal generators, Signal analysis, Sensor networks, Safety

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Proceedings Article | 22 March 2021 Presentation + Paper

Delamination detection in aerospace composite panels using convolutional autoencoders

Mahindra Rautela, Ernesto Monaco, Srinivasan Gopalakrishnan

Proceedings Volume 11593, 1159317 (2021) https://doi.org/10.1117/12.2582993

KEYWORDS: Composites, Aerospace engineering, Time-frequency analysis, Structural design, Machine learning, Inspection, Damage detection

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Proceedings Article | 27 May 2020 Presentation + Paper

Co-infused and secondary bonded composite stiffened panels in compression: numerical and experimental strength assessment combined with NDI and guided waves based SHM

E. Monaco, N. Boffa, T. Garulli, F. Ricci, D. Fanteria

Proceedings Volume 11381, 113810C (2020) https://doi.org/10.1117/12.2559068

KEYWORDS: Failure analysis, Waveguides, Structural health monitoring, Composites, Interfaces, Finite element methods, Wave propagation

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Adhesive junctions or co-infusion of skin and stiffeners represent efficient manufacturing processes for aircrafts composites stiffened panels leading to weight saving, although they have not been widely adopted yet due to certification issues and the lack of well-established design tools and procedures. Airworthiness requirements for composite structures pose major challenges to the certification of adhesively bonded or co-infused stiffened structures. FAA Advisory Circular 20-107B prescribes the methods for substantiating the limit load capacity of any bonded stiffener, the failure of which would result in catastrophic loss of the airplane. Today, composites primary structures that work mostly under compressive loads are designed following the no-buckling criteria up to Ultimate Load. Such a design approach leads to stiffer and heavier structures if compared to letting the compressed skins work in post-buckling until failure. In order to exploit the full structural potentiality of this type of structures under compressive loads new design approaches, mostly based on Finite Element Modelling, have to be developed and validated with experimental results to correctly predict the nonlinear mechanisms of load absorption beyond skin buckling onset. Furthermore state-of-the art Non-Destructive- Techniques and Structural Health Monitoring Systems can be employed for a continuous monitoring of the joints health status. In this context, the joining technique of the stringers to the skin has a particular importance; indeed, although different joining processes barely influence the linear behavior of a stiffened plate until its first instability load, they are responsible for relevant differences in the ultimate failure load. This paper presents numerical and experimental activities carried out to study the behavior of compressed stiffened plates obtained by different manufacturing processes as well as monitoring techniques of the health status of the panels by classical NDT and guided waves based SHM systems. The numerical problem has been modelled with approaches of increasing complexity, from “classical” FE models to predict the first buckling load, to post-buckling analyses up to more refined techniques including the behavior of the skin-stiffener interface.

Proceedings Article | 1 April 2019 Presentation + Paper

Investigation of manufacturing effects by strength assessment, NDI and guided waves based SHM in composite plates reinforced with bonded stringers

N. Boffa, E. Monaco, F. Ricci, F. Amoroso

Proceedings Volume 10972, 109720Y (2019) https://doi.org/10.1117/12.2516639

KEYWORDS: Manufacturing, Structural health monitoring, Composites, Waveguides, Failure analysis, Inspection, Aerospace engineering

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Sensorised structures aimed at Structural Health Monitoring implementation in aircraft components are among the most promising approaches for a next future evolution of the current maintenance procedures (and consequently for operative costs reduction) but also for relevant modifications of design rules and manufacturing processes. Adhesive bonds represent an efficient manufacturing process for composite structural parts due to the possibility to co-bond or co-cure together thin plates and stiffeners leading to weight saving, although they have not been massively employed yet. One of the showstoppers for the full implementation of adhesive bonds in composites are the airworthiness certification requirements for composite aircraft structures as presented within the FAA Advisory Circular 20-107B. In that document the general methods for substantiating the limit load capacity of any bonded stiffener, the failure of which would result in catastrophic loss of the airplane, are prescribed. Among the suggested methods, the only one really permitting to achieve the optimal bonding efficiency without the addiction of disbond stoppers (i.e. rivets), is a “repeatable and reliable non-destructive inspection techniques ensuring the strength of each joint”. This paper presents experimental activities that the authors have carried out to characterize two stiffened plates that are “nominally” equal, but obtained by different manufacturing processes; the two plates have been statically characterized performing strength tests, inspected by traditional NDI (ultrasonic C-Scan) and implementing a guided waves based SHM system designed for stringer debonding detection and characterization. A critical analysis of the experimental results as well as a comparison with the expected nominal structural performances will be presented. Afterward a comparison of the three approaches adopted for structural health status characterization before and after stiffener disbonding will be presented looking at the possible implementation of a SHM system committed at satisfying the certification requirements of the AC 20-107B.

Proceedings Article | 1 April 2019 Presentation + Paper

Hybrid structural health monitoring on a composite plate manufactured with automatic fibers placement including embedded fiber Bragg gratings and bonded piezoelectric patches

N. Boffa, E. Monaco, F. Ricci, L. Lecce, M. Barile, V. Memmolo

Proceedings Volume 10972, 109720U (2019) https://doi.org/10.1117/12.2516537

KEYWORDS: Fiber Bragg gratings, Sensors, Structural health monitoring, Optical fibers, Composites, Ferroelectric materials, Fiber optics sensors, Manufacturing, Waveguides, Liquids

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Secondary bonded or embedded sensors are usually adopted in Structural Health Monitoring of composite structures. Each type of sensor has advantages and drawbacks when used separately although their proper integrated combination may improve the overall performance of a SHM system. The aim of the present work is to evaluate the feasibility of an efficient hybrid SHM system able to sense and locate low velocity impacts and to localize eventual impact damages at their early stage with few sensors. A CFRP panel demonstrator with embedded FBGs has been fabricated by NOVOTECH srl through an advanced out-of-autoclave manufacturing process based on the following main phases: production of dry preforms laid down with a laser assisted automated fiber placement robot (AFP); insertion of the FBGs network within the stack of the preform according to the design requirements; high temperature liquid resin infusion process. Disk shaped piezo patches (PZT) are then secondary bonded to the panel. First, an impact sensing mode is enabled resorting to both PZTs and FBGs as receivers, gathering strain waves from the impact location. A material independent technique, that needs neither a priori knowledge of the material properties even for anisotropic plates nor a dense array of sensors, will be used to locate the impact. To assess the integrity of the panel after impact localization, the damage location mode is then performed using the most effective sensors, where the selection of these sensors is possible thanks to the knowledge of the impact location carried out in the previous mentioned impact sensing mode. The damage localization technique is based on guided waves generated by PZTs and sensed by both PZTs and FBGs. Again, thanks to the knowledge of the impact location, a reduced number of PZTs is selected to perform the damage localization. The main advantage of the proposed technique is the capability to sense impact events and to activate the damage localization mode only when required. Moreover, by the knowledge of the impact location, only a few sensors (sources and receivers) need to be used in favor a reduced number of acquisition channels required and acquisition data to be managed.

Proceedings Article | 27 March 2018 Presentation + Paper

Hybrid guided wave based SHM system for composite structures for impact and delamination detection combining fiber Bragg grating sensing and piezoelectric patches

N. D. Boffa, E. Monaco, L. Maio, V. Memmolo, F. Ricci, E. Mendoza, T. Kundu

Proceedings Volume 10600, 106000D (2018) https://doi.org/10.1117/12.2297694

KEYWORDS: Sensors, Fiber Bragg gratings, Structural health monitoring, Composites, Waveguides, Wave propagation, Sensing systems

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Proceedings Article | 27 March 2018 Presentation + Paper

Development of a de-icing system for aerodynamic surfaces based on ultrasonic waves

L. Maio, S. Ameduri, A. Concilio, E. Monaco, V. Memmolo, F. Ricci

Proceedings Volume 10600, 106000H (2018) https://doi.org/10.1117/12.2300780

KEYWORDS: Ferroelectric materials, Actuators, Skin, Interfaces, Ultrasonics, Aerodynamics, Finite element methods, Transducers, Aluminum, Aerospace engineering

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Proceedings Article | 5 April 2017 Presentation + Paper

Laser Doppler velocimetry and PZT sensing for the study of guided waves in a stepped aluminum plate

L. Maio, F. Ricci, V. Memmolo, N. D. Boffa, E. Monaco, A. Mal, C. Schaal

Proceedings Volume 10170, 101701S (2017) https://doi.org/10.1117/12.2260140

KEYWORDS: Wave propagation, Doppler effect, Wave plates, Nondestructive evaluation, Velocity measurements, Vibrometry, Waveguides, Aluminum, Actuators, Laser Doppler velocimetry, Transducers, Dispersion

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Proceedings Article | 5 April 2017 Presentation + Paper

Guided waves based SHM systems: parameters selection for better identification and localisation of damages in composites stiffened plates

E. Monaco, V. Memmolo, N. D. Boffa, L. Maio, F. Ricci

Proceedings Volume 10170, 101701E (2017) https://doi.org/10.1117/12.2260447

KEYWORDS: Waveguides, Structural health monitoring, Composites, Aerospace engineering, Signal generators, Structural design, Failure analysis, Signal detection, Wave propagation, Damage detection, Ultrasonics, Tomography

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Proceedings Article | 1 April 2016 Presentation + Paper

Detecting delaminations and disbondings on full-scale wing composite panel by guided waves based SHM system

E. Monaco, N. Boffa, V. Memmolo, F. Ricci, L. Maio

Proceedings Volume 9805, 98050V (2016) https://doi.org/10.1117/12.2219204

KEYWORDS: Structural health monitoring, Waveguides, Composites, Nondestructive evaluation, Damage detection, Signal analysis, Signal detection, Wave propagation, Statistical analysis, Algorithm development

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Proceedings Article | 1 April 2016 Presentation + Paper

Model assisted probability of detection for a guided waves based SHM technique

V. Memmolo, F. Ricci, L. Maio, N. Boffa, E. Monaco

Proceedings Volume 9805, 980504 (2016) https://doi.org/10.1117/12.2219306

KEYWORDS: Structural health monitoring, Composites, Probability theory, Waveguides, Tomography, Damage detection, Mathematical modeling, Wave propagation, Ultrasonics, Environmental sensing, Reliability, Statistical analysis, Inspection, Ferroelectric materials

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SPIE Journal Paper | 20 October 2015

Damage detection tomography based on guided waves in composite structures using a distributed sensor network

Vittorio Memmolo, Leandro Maio, Natalino Daniele Boffa, Ernesto Monaco, Fabrizio Ricci

OE, Vol. 55, Issue 01, 011007, (October 2015) https://doi.org/10.1117/12.10.1117/1.OE.55.1.011007

KEYWORDS: Optical tomography, Tomography, Damage detection, Waveguides, Composites, Structural health monitoring, Wave propagation, Statistical analysis, Sensors, Optical engineering

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Proceedings Article | 23 March 2015 Paper

Guided waves based SHM systems for composites structural elements: statistical analyses finalized at probability of detection definition and assessment

E. Monaco, Vittorio Memmolo, F. Ricci, Natalino Boffa, L. Maio

Proceedings Volume 9438, 94380M (2015) https://doi.org/10.1117/12.2084334

KEYWORDS: Structural health monitoring, Sensors, Statistical analysis, Composites, Reliability, Wave propagation, Waveguides, Interference (communication), Inspection, Damage detection

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Proceedings Article | 23 March 2015 Paper

Guided waves for detection of delamination and disbonding in stiffened composite panels

Fabrizio Ricci, Ernesto Monaco, Leonardo Lecce, Ajit Mal

Proceedings Volume 9438, 94380P (2015) https://doi.org/10.1117/12.2084382

KEYWORDS: Composites, Waveguides, Wave propagation, Ferroelectric materials, Receivers, Ultrasonics, Wave plates, Transducers, Signal detection, Sensors

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Proceedings Article | 15 March 2006 Paper

Autonomous health monitoring of a stiffened composite plate

Ajit Mal, Sauvik Banerjee, Fabrizio Ricci, Ernesto Monaco, L. Lecce

Proceedings Volume 6177, 617701 (2006) https://doi.org/10.1117/12.660424

KEYWORDS: Composites, Sensors, Wave propagation, Transducers, Actuators, Ultrasonics, Statistical analysis, Receivers, Wave plates, Structural health monitoring

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Proceedings Article | 29 July 2004 Paper

Influence of experimental testing set-up and geometric parameters on damping measurements

Fabrizio Ricci, Ernesto Monaco, Francesco Marulo, Tiziano Polito

Proceedings Volume 5386, (2004) https://doi.org/10.1117/12.533983

KEYWORDS: Composites, Control systems, Temperature metrology, Finite element methods, LabVIEW, Systems modeling, Manufacturing, Data modeling, Sensors, Metals

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Proceedings Article | 15 July 2002 Paper

Nondestructive technique based on vibration measurements and piezoelectric patches for monitoring corrosion phenomena

Ernesto Monaco, Mauro Fontana, Luca De Rosa, Francesco Bellucci, Leonardo Lecce

Proceedings Volume 4701, (2002) https://doi.org/10.1117/12.474648

KEYWORDS: Corrosion, Distributed interactive simulations, Nondestructive evaluation, Actuators, Sensors, Electrodes, Vibrometry, Aluminum, Metals, Statistical analysis

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Proceedings Article | 22 June 2000 Paper

Experimental activities on damage detection using magnetostrictive actuators and statistical analysis

Ernesto Monaco, Gianluca Calandra, Leonardo Lecce

Proceedings Volume 3985, (2000) https://doi.org/10.1117/12.388823

KEYWORDS: Distributed interactive simulations, Actuators, Statistical analysis, Nondestructive evaluation, Reliability, Sensors, Damage detection, Analytical research, Algorithm development, Optical simulations

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Proceedings Article | 9 June 1999 Paper

Structural damage identification using magnetostrictive actuators

Ernesto Monaco, Francesco Franco, Leonardo Lecce

Proceedings Volume 3668, (1999) https://doi.org/10.1117/12.350718

KEYWORDS: Sensors, Actuators, Distributed interactive simulations, Analytical research, Magnetic sensors, System integration, Head, Magnetostrictive materials, Smart structures, Damage detection

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