Preliminary characterization of bonding defects in multi-element spars

Concilio, Antonio; Ciminello, Monica; Apuleo, Gianvito; Kressel, Iddo; Shoham, Shay; Bardenstein, David

doi:10.1117/12.2514297

Cited by 5 publications

(5 citation statements)

References 15 publications

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“…Distributed sensing allows following adhesive effects' discontinuity along the bonding line, continuously [35]. This is very important if it is considered that such a kind of fault concentrates its effect in a limited region of the structure, so that sensors located even a few cm away do not distinguish any variation with respect to the nominal (integral) configuration [36]. Rayleigh or optical frequency domain reflectometry (OFDR) is a technique for high spatial resolution distributed sensing [37], which is implemented herein.…”

Section: Distributed Sensing By Fiber Opticsmentioning

confidence: 99%

“…The study is concentrated over a test article representing a typical aircraft wing element (Figure 6) [36]. It is made of two unidirectional carbon-epoxy plates deployed on its top and bottom, and two C-type symmetrical beams as lateral walls.…”

Section: Reference Test Article and Fe Modelmentioning

confidence: 99%

“…After these first computations and these preliminary considerations, a limited number of parameters were defined to try to assess a synthetical representation of the damage effect on the strain function. These are introduced in Figure 12 [36] and are described as follows:…”

Section: Numerical Elaborations-symmetrical Loadmentioning

confidence: 99%

See 2 more Smart Citations

De-Bonding Numerical Characterization and Detection in Aeronautic Multi-Element Spars

Concilio

Ciminello

Galasso

et al. 2022

Sensors

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Structural health monitoring has multifold aims. Concerning composite structures, the main objectives are perhaps reducing costs by shifting from scheduled to on-demand maintenance and reducing weight by removing redundant precautions as the insertion of chicken fasteners to for ensuring joint safety in cases of bonding layer fail. Adhesion defects may be classified along different types, for instance distinguishing between glue deficiency or de-bonding. This paper deals with a preliminary numerical characterization of adhesive layer imperfections on a representative aircraft component. The multipart composite spar is made of two plates and two corresponding C-beams, bonded together to form an almost squared boxed section beam. A numerical test campaign was devoted to extract relevant information from different defect layouts and to try to assess some parameters that could describe their peculiarities. A focus was then given to macroscopic evidence of fault effects behavior, as localization, reciprocal interference, impact on structural response, and so on. A proprietary code was finally used to retrieve the presence and size of the imperfections, correlating numerical outcomes with estimations. Activities were performed along OPTICOMS, a European project funded within the Clean Sky 2 Joint Technology Initiative (JTI).

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Section: Distributed Sensing By Fiber Opticsmentioning

confidence: 99%

Section: Reference Test Article and Fe Modelmentioning

confidence: 99%

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De-Bonding Numerical Characterization and Detection in Aeronautic Multi-Element Spars

Concilio

Ciminello

Galasso

et al. 2022

Sensors

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“…This unknown state is somehow correlated to the reference state according to different approaches and different damage index (DI) indicators. Other techniques take advantage of the strain difference revealed by two close sensors to detect the possible presence of flaws [ 11 , 12 , 13 , 14 , 15 ], irrespective of the static or dynamic nature of the excitation. Damage alters the stiffness and strain field distribution within the structure, even if in a very limited surrounding area.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Results of a Structural Health Monitoring System Application for Real-Time Debonding Detection on a Full-Scale Composite Spar

Ciminello

Sikorski

Galasso

et al. 2023

Sensors

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The present paper reports the outcomes of activities concerning a real-time SHM system for debonding flaw detection based on ground testing of an aircraft structural component as a basis for condition-based maintenance. In this application, a damage detection method unrelated to structural or load models is investigated. In the reported application, the system is applied for real-time detection of two flaws, kissing bond type, artificially deployed over a full-scale composite spar under the action of external bending loads. The proposed algorithm, local high-edge onset (LHEO), detects damage as an edge onset in both the space and time domains, correlating current strain levels to next strain levels within a sliding inner product proportional to the sensor step and the acquisition time interval, respectively. Real-time implementation can run on a consumer-grade computer. The SHM algorithm was written in Matlab and compiled as a Python module, then called from a multiprocess wrapper code with separate operations for data reception and data elaboration. The proposed SHM system is made of FBG arrays, an interrogator, an in-house SHM code, an original decoding software (SW) for real-time implementation of multiple SHM algorithms and a continuous interface with an external operator.

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“…The development of the SHM system, whose results are presented for a selected application concerning full-scale aircraft subcomponents, is based on distributed or FBG sensors, depending on the final objective, see refs. [36,37]. Its main, original feature stands in its adopting a non-based model algorithm, which allows it to detect the presence of one or more damage areas without previous knowledge of the structural behaviour or the availability of a validated numerical model.…”

mentioning

confidence: 99%

A Structural Health Monitoring System for Bond Line Flaws Detection on a Full-Scale Wingbox Section Demonstrator

Pellone,

Ciminello,

Mercurio

et al. 2024

Applied Mechanics

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In recent years, there has been a significant increase in the use of structural health monitoring (SHM) technologies as systems for monitoring the integrity of aircraft’s structures. The use of compact and embeddable sensor networks, like the ones based on fibre optics (FO), is particularly attractive from the perspective of releasing an integrated structural system with intrinsic sensing capacity. Usually, an SHM system architecture is completed by a dedicated algorithm that processes the data gathered from the sensors to elaborate on the level of damage currently suffered by the structure, with the further possibility of providing information to the relevant specialists involved with its supervision. One of the main SHM applications that is attracting major interest is related to the inspection and detection of anomalies in bonded joints, which is extremely relevant in many composite realizations. Aeronautical regulations allow the use of bonded joints on an aircraft’s primary structure but require the implementation of a means to ensure their absolute safety, such as the introduction of further mechanical links aimed at stopping the propagation of a possible flaw or the availability of Non-Destructive Inspection (NDI) systems to prove the absence of relevant damaged areas. Generally, the main typical defects occurring during the manufacturing of bonded joints include adhesive curing, kissing bonds, poor porosity, and poor surface preparation. The current NDI systems more widely used and available to detect defects are still inaccurate due to the lack of standard procedures for the creation of representative defects in a controlled manner, which would allow for the development of reliable methodologies and tools able to ensure the safety of a bonded joint, as required by safety regulations. This paper shows the results relative to the implementation of an SHM system developed by the Italian Aerospace Research Centre (CIRA) aimed at monitoring the bonding lines between spar caps and panels of a typical composite wingbox section and detecting faults in location and length. The work was performed during typical ground static tests by using a fibre optical sensing network embedded within relevant adhesive paste layers during the manufacturing process of the structure. In the reported investigation, the SHM system assumed the function of an NDI system tool. The results show that the developed SHM system has good reliability for the detection of both the position and size of damage areas that were artificially inserted within the test article during the bonding phase, showing its potential as a candidate to be used as a tool to verify the conditions of a bonded joint, as required by aviation authorities’ regulations.

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Preliminary characterization of bonding defects in multi-element spars

Cited by 5 publications

References 15 publications

De-Bonding Numerical Characterization and Detection in Aeronautic Multi-Element Spars

De-Bonding Numerical Characterization and Detection in Aeronautic Multi-Element Spars

Preliminary Results of a Structural Health Monitoring System Application for Real-Time Debonding Detection on a Full-Scale Composite Spar

A Structural Health Monitoring System for Bond Line Flaws Detection on a Full-Scale Wingbox Section Demonstrator

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