Damage Detection of CFRP Stiffened Panels by Using Cross-Correlated Spatially Shifted Distributed Strain Sensors

This paper presents a cross-correlation function-based method applied to a spatially shifted differential strain readout vectors using distributed sensors under backscattering random noise and impact excitations. Structural damage is generated by low/medium energy impact on two aeronautical 24-ply CFRP (carbon fiber reinforced plastic) stiffened panels. Two different drop impact locations, two different sensor layouts and two different post-impact solicitations are provided for a skin-stringer debonding detection and length estimation. The differential signal with respect to an arbitrarily selected grounding is used. Then the effects of noise filtering are evaluated post-processing the differential signal by cross-correlating two strain vectors having one sensor gauge position lag. A Rayleigh backscattering sensing technology, with 5 mm of spatial resolution, is used to log the strain map. The results show a good coherence with respect to the NDI (nondestructive inspection) performed by ultrasonic C-scan (an ultrasonic imaging system) flaw detector

SMA blade twist system: from the requirements to the demonstration in relevant environment

In the present work, an overview is provided on the activities performed by CIRA, DLR and Univ of Bristol to develop and test a morphing system aimed at altering the twist of a blade to enhance the performance of the main rotor. The activities were performed within the research Project of “Shape Adaptive Blades for Rotorcraft Efficiency” (SABRE, H2020, 2017-2021), a Consortium constituted by six Partners (Univ. of Bristol – leader, Univs. of Munich, Delft and Swansea and the research centers of DLR and CIRA). Moving from the original features of the blade and the requirements of the reference rotorcraft, a layout of the architecture was sketched. A refined numerical model was then implemented to accurately predict the functionality of the concept and verify its safety compliance with the test facilities it was conceived for. Laboratory tests were thus performed on a dedicated prototype. Finally, on this basis, two other demonstrators were built and finally tested in the just mentioned wind tunnel and whirl tower plants

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

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)

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

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

Multicentre experience with MGuard net protective stent in ST-elevation myocardial infarction: Safety, feasibility, and impact on myocardial reperfusion.

.Objective: To report, for the first time, angiographic and ECG results as well as in-hospital and 1-month clinical follow-up, after MGuard net protective stent (Inspire-MD, Tel-Aviv, Israel-MGS) implantation in consecutive, not randomized, STEMI patients undergoing primary or rescue PCI. Background: Distal embolization may decrease coronary and myocardial reperfusion after percutaneous coronary intervention (PCI), in ST-elevation myocardial infarction (STEMI) setting. Methods: One-hundred consecutive patients underwent PCI, with MGS deployment for STEMI, in five different high-volume PCI centres. Sixteen patients presented cardiogenic shock at admission. Results: All patients underwent successful procedures: mean TIMI flow grade and mean corrected TIMI frame count-cTFC(n)-improved from baseline values to 2.85 +/- 0.40 and to 17.20 +/- 10.51, respectively, with a mean difference in cTFC(n) between baseline and postprocedure of 46.88 +/- 31.86. High-myocardial blush grade (90% MBG 3; 10% MBG 2) was also achieved in all patients. Sixty minutes post-PCI, a high rate (90%) of complete (>/=70%) ST-segment resolution was achieved. At in-hospital follow-up, seven deaths occurred: noteworthy, 5 of 16 patients with cardiogenic shock at admission died. After hospital discharge, no Major Adverse Cardiac Events have been reported up to 30-day follow-up. Conclusions: MGS might represent a safe and feasible option for PCI in STEMI patients, providing high perfusional and ECG improvement. Further randomized trials comparing this strategy with the conventional one are needed in the near future to assess the impact on clinical practice of this strateg

Whirl Tower Demonstration of an SMA Blade Twist System

This paper focuses on the development and demonstration of a novel blade morphing system within a whirl tower facility. The scope is to investigate the behavior of the proposed architecture under representative loads, demonstrating its capability to alter the blade original shape in operation under centrifugal, aerodynamic, and internal forces. The morphing concept was developed inside the European project “Shape Adaptive Blades for Rotorcraft Efficiency”, SABRE, and consists of a shape memory alloy system able to change the original twist law and, in this way, enhance rotor performance at certain specific regimes, such as hover and vertical flight. These phases, indeed, are generally penalized with respect to other more extended flight regimes (cruise). The work starts with an overview of the research in the field of morphing, with specific reference to the researches envisaging rotary wing demonstrations. Then, an overview of the morphing twist concept is provided, with particular attention paid to those features particularly suited for the whirl tower representative test environment. The laboratory characterization and commissioning operations are illustrated. Then, the task of the installation of the prototype on the whirl tower facility is described together with the testing modality adopted. Finally, the results of the test campaign are illustrated and critically discussed, providing the reader with insights and possible future steps to be taken in further research. The impact on the morphing capability of the following different parameters was investigated: the number of the prototype segments switched on, the speed and thus the centrifugal actions, and the angles of attack. The stiffening effect due to centrifugal actions was quantified through the measurement of the actual twist and the internal deformation. The link between speed, angle of attack at root, and twist and flap angles was also tracked, building a database useful for the comprehension of the phenomenon, and for the assessment of numerical predictive models. The achieved results highlighted the capability of the system to produce a twist angle matching the target of 8° per blade radius; this figure is related to a potential power saving of 10% in hover and vertical flight and an improvement of about 1% on the over-all efficiency of the rotorcraft

EXPERIMENTAL TESTS OF A SMA BASED BLADE TWIST SYSTEM: WIND TUNNEL AND WHIRL TOWER OUTCOMES

In this work, attention is paid on two specific moments foreseen in the European Project "Shape Adaptive Blades for Rotorcraft Efficiency": the test validation in wind tunnel and whirl tower representative environments of a morphing architecture aiming at altering the twist law of an helicopter blade. The architecture, based on Shape Memory Alloy technology, was tested in the abovementioned environments to get enough information on its functionality under representative loads and on its capability of producing significant variations of the original performance. The wind tunnel tests held at the University of Bristol, captured the effect of the progressive span wise twist activation, highlighting the capability of improving the aerodynamic efficiency. The whirl tower test campaign organized at the DLR plant, demonstrated the capability of the system of altering its original twist, even in presence of centrifuge forces tending to stretch the blade and, thus, to make it stiffener. In addition, twist related effects were measured, as the produced flapping motion. The achieved results proved, in relevant environment, the effectiveness of the architecture both from a functional (additional twist production) and an effectiveness (alteration of the aerodynamics) point of view. The experimental outcomes paved the way to a critical overview aiming at identifying potential issues and relevant approaches for further increase of the technology readiness level of the concept. Copyright © 2022 by ASME

Safety and feasibility of balloon aortic valvuloplasty in non-TAVI centers: The "BAV for life" experience

Objectives: To evaluate the safety and the feasibility of balloon aortic valvuloplasty (BAV) procedure made by trained operators in centers not performing transcatheter aortic valve implantation (TAVI). Background: BAV is a valuable therapeutic tool for patients with symptomatic severe aortic valve stenosis (AS) at prohibitive risk for TAVI or surgery. Methods: Consecutive high-risk AS patients underwent BAV in five non-TAVI centers, where BAV operators had completed a 6-month training period in high-volume TAVI centers (Group A). All clinical, echocardiographic, and procedural data were prospectively collected and compared with data of patients treated in TAVI center (Group B). Results: Between June 2016 and June 2017, 55 patients (83.9 ± 7.0 years) were enrolled: 25 in Group A and 30 in Group B. After BAV, a substantial reduction of the peak-to-peak aortic valve gradient was obtained in both groups (-35.3 ± 15.2 vs -28.8 ± 13.9 mmHg, P =0.25). No major bleeding or vascular complications occurred. In-hospital death was observed in three patients of Group A and two patients of Group B (P =0.493). The mean follow-up time was 303 ± 188 days; no patients were lost. The 1-year survival free from overall death (Group A 75.8% vs Group B 68.8%; P =0.682) and heart failure rehospitalization (Group A 73.0% vs Group B 66.8%; P =0.687) was similar in the two groups. At multivariable analysis, low left ventricular (LV) ejection fraction (HR: 0.943; P = 0.011) and cardiogenic shock (HR: 5.128; P = 0.002) at admission were independent predictors of mortality. Conclusions: BAV is a safe and effective procedure that can be performed by trained operators in centers not performing TAVI

Antithrombotic strategies in the catheterization laboratory for patients with acute coronary syndromes undergoing percutaneous coronary interventions: insights from the EmploYEd antithrombotic therapies in patients with acute coronary Syndromes HOspitalized in iTalian cardiac care units Registry

AimsIn the last decades, several new therapies have emerged for the treatment of acute coronary syndromes (ACS). We sought to describe real-world patterns of use of antithrombotic treatments in the catheterization laboratory for ACS patients undergoing percutaneous coronary interventions (PCI).MethodsEmploYEd antithrombotic therapies in patients with acute coronary Syndromes HOspitalized in iTalian cardiac care units was a nationwide, prospective registry aimed to evaluate antithrombotic strategies employed in ACS patients in Italy.ResultsOver a 3-week period, a total of 2585 consecutive ACS patients have been enrolled in 203 cardiac care units across Italy. Among these patients, 1755 underwent PCI (923 with ST-elevation myocardial infarction and 832 with non-ST-elevation ACS). In the catheterization laboratory, unfractioned heparin was the most used antithrombotic drug in both ST-elevation myocardial infarction (64.7%) and non-ST-elevation ACS (77.5%) undergoing PCI and, as aspirin, bivalirudin and glycoprotein IIb/IIIa inhibitors (GPIs) more frequently employed before or during PCI compared with the postprocedural period. Any crossover of heparin therapy occurred in 36.0% of cases, whereas switching from one P2Y12 inhibitor to another occurred in 3.7% of patients. Multivariable analysis yielded several independent predictors of GPIs and of bivalirudin use in the catheterization laboratory, mainly related to clinical presentation, PCI complexity and presence of complications during the procedure.ConclusionIn our contemporary, nationwide, all-comers cohort of ACS patients undergoing PCI, antithrombotic therapies were commonly initiated before the catheterization laboratory. In the periprocedural period, the most frequently employed drugs were unfractioned heparin, leading to a high rate of crossover, followed by GPIs and bivalirudin, mainly used during complex PCI.Clinical Trial Registration. URLhttp://www.clinicaltrials.gov. Unique identifier: NCT02015624

Safety and feasibility of balloon aortic valvuloplasty in non-TAVI centers: The “BAV for life” experience

Objectives: To evaluate the safety and the feasibility of balloon aortic valvuloplasty (BAV) procedure made by trained operators in centers not performing transcatheter aortic valve implantation (TAVI). Background: BAV is a valuable therapeutic tool for patients with symptomatic severe aortic valve stenosis (AS) at prohibitive risk for TAVI or surgery. Methods: Consecutive high-risk AS patients underwent BAV in five non-TAVI centers, where BAV operators had completed a 6-month training period in high-volume TAVI centers (Group A). All clinical, echocardiographic, and procedural data were prospectively collected and compared with data of patients treated in TAVI center (Group B). Results: Between June 2016 and June 2017, 55 patients (83.9 ± 7.0 years) were enrolled: 25 in Group A and 30 in Group B. After BAV, a substantial reduction of the peak-to-peak aortic valve gradient was obtained in both groups (−35.3 ± 15.2 vs −28.8 ± 13.9 mmHg, P =0.25). No major bleeding or vascular complications occurred. In-hospital death was observed in three patients of Group A and two patients of Group B (P =0.493). The mean follow-up time was 303 ± 188 days; no patients were lost. The 1-year survival free from overall death (Group A 75.8% vs Group B 68.8%; P =0.682) and heart failure rehospitalization (Group A 73.0% vs Group B 66.8%; P =0.687) was similar in the two groups. At multivariable analysis, low left ventricular (LV) ejection fraction (HR: 0.943; P = 0.011) and cardiogenic shock (HR: 5.128; P = 0.002) at admission were independent predictors of mortality. Conclusions: BAV is a safe and effective procedure that can be performed by trained operators in centers not performing TAVI