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Study of dynamic underwater implosion mechanics using digital image correlation

PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 2014年第2172期470卷

作者： Gupta, Sachin Parameswaran, Venkitanarayanan Sutton, Michael A. Shukla, Arun Univ Rhode Isl Dept Mech Ind & Syst Engn Dynam Photo Mech Lab Kingston RI 02881 USA Indian Inst Technol Dept Mech Engn Kanpur 208016 Uttar Pradesh India Univ S Carolina Dept Mech Engn Columbia SC 29208 USA

The physical processes associated with the implosion of cylindrical tubes in a hydrostatic underwater environment were investigated using high-speed three-dimensional digital image correlation (3D DIC). This study emphasizes visualization and understanding of the real-time deformation of the implodable volume and the associated fluid-structure interaction phenomena. Aluminium 6061-T6 cylindrical tubes were used as the implodable volumes. Dynamic tourmaline pressure transducers were placed at selected locations to capture the pressure history generated during each implosion event. A series of small-scale calibration experiments were first performed to establish the applicability of 3D DIC for measuring the deformation of submerged objects. The results of these experiments indicated that the effects of refraction due to water and the optical windows can be accounted for by evaluation of the camera's intrinsic and extrinsic parameters using a submerged calibration grid when the surface normal of the optical windows is collinear with the camera's optical axis. Each pressure history was synchronized with its respective high-speed DIC measurements. DIC results showed that the highest rate of increase in contact area correlates to the largest pressure spike during the implosion process. The results also indicated that, for a given diameter, longer implodable volumes generated higher pressure spikes.

关键词： digital image correlation submerged objects implosion implodable volume fluid-structure interaction high-speed stereo-photography

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Compliant Topology Optimization for Planar Passive Flap Micro Valve

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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2014年第10期14卷 7585-7591页

作者： Yoon, Gil Ho Hanyang Univ Sch Mech Engn Seoul 133791 South Korea

This paper reports the compliant topology optimization for planar passive flap micro valve considering fluid-structure interaction with a monolithic approach. Although flap valve type check valve is easy to manufacture and use for the applications for Bio/Nano/MEMS, its structural optimization has been seldom conducted so far. The size of the Bio/Nano/MEMS devices becomes smaller and the simple straight type micro valve structure is required to be optimized considering fluid speed. To address this optimization problem, the structural topology optimization scheme which designs optimal topologies is applied for a flap type check valve structure. To consider the coupling effects of fluid domain and structural domain, the monolithic finite element approach is employed. In the new analysis approach, solid domain is simulated by introducing the inverse permeability in the Navier-Stokes equation and the fluid stress filter in the linear elasticity equation. Also it is a new idea that fluid domain is simulated by finite elements with a weak Young's modulus in the linear elasticity equation. The mutual couplings between fluid and structure are considered by the introduction of the deformation tensor which is one of the basic concepts of the continuum mechanism. By distributing material properties inside a design domain for compliant flap, optimal flap structures can be constructed with different fluid speeds. By investigating the optimal layouts of several passive flap designs, we prove that the structural topology optimization can provide optimal layouts for Bio, Nano, and MEMS applications.

关键词： Passive Flap structure Topology Optimization fluid-structure interaction

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RESPONSE CONTROL IN fluid-SMART structure interaction

RESPONSE CONTROL IN FLUID-SMART STRUCTURE INTERACTION

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ASME International Design Engineering Technical Conferences/Computers and Information in Engineering Conference

作者： To, C. W. S. Univ Nebraska Dept Mech Engn Lincoln NE 68588 USA

ISBN: (纸本)9780791843277

A formulation with computational procedure for the response control in fluid-smart structure interaction is presented. It exploits the features of the smart triangular shell finite elements developed earlier by the author and his associate, the double asymptotic approximation for fluid-structure interaction of Geers, and the finite element-cum-boundary element method that was proposed by To and O'Grady. To provide a better understanding of the interplay between the structural responses and the applied voltage of the piezoelectric layers, computed results of a three-layered simply-supported plate structure were presented. It was observed that significant deformation reduction can be achieved with applied voltage indicating that with the smart shell finite elements desired deformation at chosen locations of the submerged system can be specified.

关键词： fluid-structure interaction finite elements boundary elements feedback control smart structures

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Mechanical action of the blood onto atheromatous plaques: influence of the stenosis shape and morphology

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COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING 2014年第5期17卷 527-538页

作者： Belzacq, Tristan Avril, Stephane Leriche, Emmanuel Delache, Alexandre Ecole Natl Super Mines Ctr Ingn & Sante CNRS UMR 5146 F-42023 St Etienne 2 France Univ Lille Lab Mecan Lille F-59655 Villeneuve Dascq France Univ Lyon LMFA F-42023 St Etienne 2 France Univ St Etienne Fac Sci & Tech F-42023 St Etienne 2 France

The vulnerability of atheromatous plaques in the carotid artery may be related to several factors, the most important being the degree of severity of the endoluminal stenosis and the thickness of the fibrous cap. It has recently been shown that the plaque length can also affect the mechanical response significantly. However, in their study on the effect of the plaque length, the authors did not consider the variations of the plaque morphology and the shape irregularities that may exist independently of the plaque length. These aspects are developed in this paper. The mechanical interactions between the blood flow and an atheromatous plaque are studied through a numerical model considering fluid-structure interaction. The simulation is achieved using the arbitrary Lagrangian-Eulerian scheme in the COMSOL TM commercial finite element package. The stenosis severity and the plaque length are, respectively, set to 45% and 15mm. Different shapes of the stenosis are modelled, considering irregularities made of several bumps over the plaque. The resulting flow patterns, wall shear stresses, plaque deformations and stresses in the fibrous cap reveal that the effects of the blood flow are amplified if the slope upstream stenosis is steep or if the plaque morphology is irregular with bumps. More specifically, the maximum stress in the fibrous cap is 50% larger for a steep slope than for a gentle slope. These results offer new perspectives for considering the shape of plaques in the evaluation of the vulnerability.

关键词： plaque morphology stenosis blood flow fluid-structure interaction vascular biomechanics numerical simulation

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Effect of exercise on blood flow through the aortic valve: a combined clinical and numerical study

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COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING 2014年第16期17卷 1821-1834页

作者： Bahraseman, Hamidreza Ghasemi Hassani, Kamran Navidbakhsh, Mahdi Espino, Daniel M. Sani, Zahra Alizadeh Fatourae, Nasser Islamic Azad Univ Sci & Res Branch Dept Biomech Tehran Iran Iran Univ Sci & Technol Dept Mech Engn Tehran Iran Univ Birmingham Sch Mech Engn Birmingham W Midlands England Univ Tehran Med Sci Dept Cardiovasc Imaging Med & Res Ctr Tehran Iran Amirkabir Univ Technol Dept Biomed Engn Tehran Iran

The aim of this study was to measure the cardiac output and stroke volume for a healthy subject by coupling an echocardiogram Doppler (echo-Doppler) method with a fluid-structure interaction (FSI) simulation at rest and during exercise. Blood flow through aortic valve was measured by Doppler flow echocardiography. Aortic valve geometry was calculated by echocardiographic imaging. An FSI simulation was performed, using an arbitrary Lagrangian-Eulerian mesh. Boundary conditions were defined by pressure loads on ventricular and aortic sides. Pressure loads applied brachial pressures with (stage 1) and without (stage 2) differences between brachial, central and left ventricular pressures. FSI results for cardiac output were 15.4% lower than Doppler results for stage 1 (r = 0.999). This difference increased to 22.3% for stage 2. FSI results for stroke volume were undervalued by 15.3% when compared to Doppler results at stage 1 and 26.2% at stage 2 (r = 0.94). The predicted mean backflow of blood was 4.6%. Our results show that numerical methods can be combined with clinical measurements to provide good estimates of patient-specific cardiac output and stroke volume at different heart rates.

关键词： cardiac output echo-Doppler flow fluid-structure interaction stroke volume

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A continuum model for platelet plug formation, growth and deformation

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014年第12期30卷 1541-1557页

作者： Storti, F. van de Vosse, F. N. Eindhoven Univ Technol Dept Biomed Engn NL-5600 MB Eindhoven Netherlands

A numerical framework for modelling platelet plug dynamics is presented in this work. It consists of an extension of a biochemical and plug growth model with a solid mechanics model for the plug coupled with a fluid-structure interaction model for the blood flow-plug system. The platelet plug is treated as a neo-Hookean elastic solid, of which the implementation is based on an updated Lagrangian approach. The framework is applied to different haemodynamic configurations coupled with different shear moduli of the plug. Results about plug growth, shape and size, as well as the stress distribution, are shown. Based on the simulations performed, we conclude that the deformability of the platelet plug is essential for its growth. Copyright (c) 2014 John Wiley & Sons, Ltd.

关键词： platelet plug development platelet plug stress haemodynamics continuum model updated Lagrangian formulation fluid-structure interaction

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Study of flexible fin and compliant joint stiffness on propulsive performance: theory and experiments

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BIOINSPIRATION & BIOMIMETICS 2014年第3期9卷 036011页

作者： Kancharala, A. K. Philen, M. K. Virginia Polytech Inst & State Univ Blacksburg VA 24061 USA

The caudal fin is a major source of thrust generation in fish locomotion. Along with the fin stiffness, the stiffness of the joint connecting the fish body to the tail plays a major role in the generation of thrust. This paper investigates the combined effect of fin and joint flexibility on propulsive performance using theoretical and experimental studies. For this study, fluid-structure interaction of the fin has been modeled using the 2D unsteady panel method coupled with nonlinear Euler-Bernoulli beam theory. The compliant joint has been modeled as a torsional spring at the leading edge of the fin. A comparison of self-propelled speed and efficiency with parameters such as heaving and pitching amplitude, oscillation frequency, flexibility of the fin and the compliant joint is reported. The model also predicts the optimized stiffnesses of the compliant joint and the fin for maximum efficiency. Experiments have been carried out to determine the effect of fin and joint stiffness on propulsive performance. Digital image correlation has been used to measure the deformation of the fins and the measured deformation is coupled with the hydrodynamic model to predict the performance. The predicted theoretical performance behavior closely matches the experimental values.

关键词： flexible foil propulsion compliant joint stiffness caudal fin and peduncle self-propelled speed digital image correlation unsteady panel method fluid-structure interaction

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ALE Formulation and WEB-Method Approximation for a fluid structure interaction Problem on Carotids

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International Conference on Advancements of Medicine and Health Care Through Technology

作者： Maierean, A. M. I. Tech Univ Cluj Napoca Romania

ISBN: (纸本)9783642042911

Treating fluid-structure interaction problems on carotids, implies taking into account that when blood is pumped by the heart through arteries, large nonlinear deformation of the domain occur. This paper reviews the experimental use of the Arbitrary Lagrangian Eulerian technique over the complex geometry of the carotids, which allows the construction of a mobile mesh chosen independently from the material motion in order to minimize the mesh distortion. In a new approach weighted extended B splines are used as basis functions on the tensor product grid.

关键词： fluid-structure interaction ALE method web FEM

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Flexible propulsors in ground effect

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BIOINSPIRATION & BIOMIMETICS 2014年第3期9卷 036008页

作者： Quinn, Daniel B. Lauder, George V. Smits, Alexander J. Princeton Univ Dept Mech & Aerosp Engn Princeton NJ 08544 USA Harvard Univ Dept Organismal & Evolutionary Biol Cambridge MA 02138 USA Monash Univ Clayton Vic 3800 Australia

We present experimental evidence for the hydrodynamic benefits of swimming 'in ground effect', that is, near a solid boundary. This situation is common to fish that swim near the substrate, especially those that are dorsoventrally compressed, such as batoids and flatfishes. To investigate flexible propulsors in ground effect, we conduct force measurements and particle image velocimetry on flexible rectangular panels actuated at their leading edge near the wall of a water channel. For a given actuation mode, the panels swim faster near the channel wall while maintaining the same propulsive economy. In conditions producing net thrust, panels produce more thrust near the ground. When operating in resonance, swimming near the ground can also increase propulsive efficiency. Finally, the ground can act to suppress three-dimensional modes, thereby increasing thrust and propulsive efficiency. The planform considered here is non-biological, but the hydrodynamic benefits are likely to apply to more complex geometries, especially those where broad flexible propulsors are involved such as fish bodies and fins. Such fish could produce more thrust by swimming near the ground, and in some cases do so more efficiently.

关键词： fluid dynamics ground effect fluid-structure interaction biolocomotion benthic fish

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Tsunami Modeling, fluid Load Simulation, and Validation Using Geospatial Field Data

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JOURNAL OF STRUCTURAL ENGINEERING 2014年第8期140卷

作者： Yim, Solomon C. Olsen, Michael J. Cheung, Kwok Fai Azadbakht, Mohsen Oregon State Univ Sch Civil & Construct Engn Corvallis OR 97331 USA Univ Hawaii Manoa Dept Ocean & Resources Engn Honolulu HI 96822 USA

This paper presents an integrated, interdisciplinary methodology incorporating multiphysics, multiscale numerical modeling and simulation from tsunami generation, propagation, and inundation to subsequent coupled structural response and associated fluid loads. This novel, cohesive approach performs these simulations across a large spectrum of scales, enabling structural engineers to take full advantage of the detail available in recent advances in tsunami modeling, geospatial data collection, and computational structural mechanics. Extensive seismic networks, geodetic instruments, and water-level stations provide unprecedented data sets, enabling one to model, simulate and reconstruct tsunami events with high fidelity. A number of coordinated, ground-based surveys also collect valuable, time-sensitive quantitative information to improve understanding of structural response to tsunami loading following events. Recently, some of these surveys include high-resolution LIDAR measurements, which provide critical geospatial information to link field observations, topographic mapping, and structural performance to create and validate numerical models, enabling quantification and understanding of structural response and failure modes resulting from tsunami forces. The presented methodology is demonstrated through a case study of a building component which structurally survived the 2011 Tohoku tsunami. (C) 2014 American Society of Civil Engineers.

关键词： Tsunami LIDAR Simulation Computation Finite-element modeling fluid-structure interaction Analysis and computation

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