Damage detection through structural intensity and vibration based techniques

Petrone, G.,Carzana, A.,Ricci, F.,De Rosa, S. Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.6

The development systems for the Structural Health Monitoring has attracted considerable interest from several engineering fields during the last decades and more specifically in the aerospace one. In fact, the introduction of those systems could allow the transition of the maintenance strategy from a scheduled basis to a condition-based approach providing cost benefits for the companies. The research presented in this paper consists of a definition and next comparison of four methods applied to numerical measurements for the extraction of damage features. The first method is based on the determination of the Structural Intensity field at the on-resonance condition in order to acquire information about the dissipation of vibrational energy throughout the structure. The Damage Quantification Indicator and the Average Integrated Global Amplitude Criterion methods need the evaluation of the Frequency Response Function for a healthy plate and a damaged one. The main difference between these two parameters is their mathematical definition and therefore the accuracy of the scalar values provided as output. The fourth and last method is based on the Mode-shape Curvature, a FRF-based technique which requires the application of particular finite-difference schemes for the derivation of the curvature of the plate. All the methods have been assessed for several damage conditions (the shape, the extension and the intensity of the damage) on two test plates: an isotropic (steel) plate and a 4-plies composite plate.

Modeling of RC Frame Buildings for Progressive Collapse Analysis

Floriana Petrone,Li Shan,Sashi K. Kunnath 한국콘크리트학회 2016 International Journal of Concrete Structures and M Vol.10 No.1

The progressive collapse analysis of reinforced concrete (RC) moment-frame buildings under extreme loads is discussed from the perspective of modeling issues. A threat-independent approach or the alternate path method forms the basis of the simulations wherein the extreme event is modeled via column removal scenarios. Using a prototype RC frame building, issues and considerations in constitutive modeling of materials, options in modeling the structural elements and specification of gravity loads are discussed with the goal of achieving consistent models that can be used in collapse scenarios involving successive loss of loadbearing columns at the lowest level of the building. The role of the floor slabs in mobilizing catenary action and influencing the progressive collapse response is also highlighted. Finally, an energy-based approach for identifying the proximity to collapse of regular multi-story buildings is proposed.

Song of My Seoul

Augusta Petrone The Academy of Korean Studies 1966 Korea Journal Vol.6 No.9

Large Physisorption Strain in Chemical Vapor Deposition of Graphene on Copper Substrates

He, Rui,Zhao, Liuyan,Petrone, Nicholas,Kim, Keun Soo,Roth, Michael,Hone, James,Kim, Philip,Pasupathy, Abhay,Pinczuk, Aron American Chemical Society 2012 Nano letters Vol.12 No.5

<P>Graphene single layers grown by chemical vapor deposition on single crystal Cu substrates are subject to nonuniform physisorption strains that depend on the orientation of the Cu surface. The strains are revealed in Raman spectra and quantitatively interpreted by molecular dynamics (MD) simulations. An average compressive strain on the order of 0.5% is determined in graphene on Cu(111). In graphene on Cu (100), MD simulations interpret the observed highly nonuniform strains.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-5/nl300397v/production/images/medium/nl-2012-00397v_0001.gif'></P>

Modelling of aluminium foam sandwich panels

D'Alessandro, Vincenzo,Petrone, Giuseppe,De Rosa, Sergio,Franco, Francesco Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.13 No.4

Aluminium Foam Sandwich (AFS) panels are becoming always more attractive in transportation applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight(R) foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.

Treatment of patients with severe traumatic brain injury: a 7-year single institution experience

Corrado P. Marini,Patrizio Petrone,John McNelis,Erin Lewis,Anna Liveris,Michael F. Stiefel 대한신경집중치료학회 2021 대한신경집중치료학회지 Vol.14 No.1

Background: This study was designed to compare the efficacy of multimodality monitoring and goal-directed therapy protocol (MM&GDTP), in patients with Glasgow Coma Scale (GCS) scores ≤8 with the conventional intracranial pressure (ICP)-cerebral perfusion pressure (CPP) treatment. Methods: The study was divided into two time periods, a 2-year historic period in which severe traumatic brain injury (sTBI) patients were treated with an ICP-CPP targeted strategy and a 5-year intervention period during which MM&GDTP was utilized. Patients with unsurvivable brain injuries were excluded. Variables of interest included mechanism of injury, age, sex, hemodynamics, GCS score, abbreviated injury score–head (AIS-H), Marshall Class, injury severity score, decompressive craniectomy, ventilator/intensive care unit days, length of stay, predicted mortality by corticosteroid randomization after significant head injury model, functional outcome, and mortality. Results: The study group comprised 810 sTBI patients, aged 14–93 years, admitted during a 7-year period; of these patients, 67 and 99 AIS-H≥4 and Marshall Class ≥III were included in control and intervention groups, respectively. The control group was treated with an ICP-CPP targeted approach, while the intervention group with an MM&GDTP. At presentation and after resuscitation, patients in the intervention group required a higher CPP to reach the endpoints of therapy. The MM&GDTP decreased mortality from 34.3% to 23.2%, yielding a 32.3% improvement in overall survival and improved functional outcome as measured by Glasgow Outcome Scale >3 (MM&GDTP vs. ICP-CPP: 50/99 vs. 15/67, P=0.003). Conclusion: Institution of MM&GDTP targeted to threshold-defined values improves functional outcomes and may reduce mortality among patients with sTBI compared to that of patients receiving an ICP-CPP–based treatment.

Modelling of aluminium foam sandwich panels

Vincenzo D’Alessandro,Giuseppe Petrone,Sergio De Rosa,Francesco Franco 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.13 No.4

applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight R foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.

Feasibility and Accuracy of Transduodenal Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Solid Lesions Using a 19-Gauge Flexible Needle: A Multicenter Study

Germana de Nucci,Maria Chiara Petrone,Nicola Imperatore,Edoardo Forti,Roberto Grassia,Silvia Giovanelli,Laura Ottaviani,Vincenzo Mirante,Giuseppe Sabatino,Carlo Fabbri,Mauro Manno,Paolo Giorgio Arcidi 대한소화기내시경학회 2021 Clinical Endoscopy Vol.54 No.2

Background/Aims: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the go-to method for obtaining samplesfrom gastrointestinal tract and pancreatic lesions. When the transduodenal approach is utilized, the use of a more flexible needle,such as a nitinol 19-gauge (G) needle, has been recommended. The aim of this study was to evaluate the feasibility and accuracy of19-G flexible aspiration needles in obtaining samples from solid lesions through a transduodenal approach. Methods: This was a retrospective analysis of prospectively collected data from eight Italian endoscopy centers. Consecutive patientswith solid lesions who underwent transduodenal EUS-FNA with a 19-G flexible needle were included. Results: A total of 201 patients were enrolled. According to histology, EUS, radiology and 12 months of follow-up, 151 patientshad malignant lesions and 50 patients had benign lesions. EUS-FNA was feasible in all cases. An adequate histologic sample wasobtained in all except eight cases (96.1%). The sensitivity of EUS-FNA was 92.1% (95% confidence interval [CI], 86.8%–95.7%), andthe specificity was 100% (95% CI, 90.5%–100%). The positive predictive value was 100% (95% CI, 93.4%–100%), and the negativepredictive value was 74% (95% CI, 62.8%–82.7%). The diagnostic accuracy was 93.5% (95% CI, 89.2%–96.5%). Conclusions: The transduodenal approach for obtaining samples from solid lesions using a 19-G flexible needle seems feasible andaccurate.

Flexible and Transparent MoS₂ Field-Effect Transistors on Hexagonal Boron Nitride-Graphene Heterostructures

Lee, Gwan-Hyoung,Yu, Young-Jun,Cui, Xu,Petrone, Nicholas,Lee, Chul-Ho,Choi, Min Sup,Lee, Dae-Yeong,Lee, Changgu,Yoo, Won Jong,Watanabe, Kenji,Taniguchi, Takashi,Nuckolls, Colin,Kim, Philip,Hone, James American Chemical Society 2013 ACS NANO Vol.7 No.9

<P>Atomically thin forms of layered materials, such as conducting graphene, insulating hexagonal boron nitride (hBN), and semiconducting molybdenum disulfide (MoS<SUB>2</SUB>), have generated great interests recently due to the possibility of combining diverse atomic layers by mechanical “stacking” to create novel materials and devices. In this work, we demonstrate field-effect transistors (FETs) with MoS<SUB>2</SUB> channels, hBN dielectric, and graphene gate electrodes. These devices show field-effect mobilities of up to 45 cm<SUP>2</SUP>/Vs and operating gate voltage below 10 V, with greatly reduced hysteresis. Taking advantage of the mechanical strength and flexibility of these materials, we demonstrate integration onto a polymer substrate to create flexible and transparent FETs that show unchanged performance up to 1.5% strain. These heterostructure devices consisting of ultrathin two-dimensional (2D) materials open up a new route toward high-performance flexible and transparent electronics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-9/nn402954e/production/images/medium/nn-2013-02954e_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn402954e'>ACS Electronic Supporting Info</A></P>

An investigation on the vibrations of laminated shells under aeroacoustic loads using a WFE approach

Errico, Fabrizio,Franco, F.,Ichchou, M.,De Rosa, S.,Petrone, G. Techno-Press 2019 Advances in aircraft and spacecraft science Vol.6 No.6

The present work investigates the effect on the flow-induced vibrations of the lay-up sequence of composite laminated axisymmetric structures, using an hybrid approach based on a wave finite element and a transfer matrix method. The structural vibrations, under deterministic distributed pressure loads, diffuse acoustic field and turbulent boundary layer excitations, are analysed and compared. A multi-scale approach is used for the dynamic analysis of finite structures, using an elementary periodic subsystem. Different flow regimes and shell curvatures are analysed and the computational efficiency is also discussed.