Academic literature on the topic 'Elastodynamics Systems'

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Journal articles on the topic "Elastodynamics Systems"

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Achenbach, Jan D. "Reciprocity and Related Topics in Elastodynamics." Applied Mechanics Reviews 59, no. 1 (January 1, 2006): 13–32. http://dx.doi.org/10.1115/1.2110262.

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Reciprocity theorems in elasticity theory were discovered in the second half of the 19th century. For elastodynamics they provide interesting relations between two elastodynamic states, say states A and B. This paper will primarily review applications of reciprocity relations for time-harmonic elastodynamic states. The paper starts with a brief introduction to provide some historical and general background, and then proceeds in Sec. 2 to a brief discussion of static reciprocity for an elastic body. General comments on waves in solids are offered in Sec. 3, while Sec. 4 provides a brief summary of linearized elastodynamics. Reciprocity theorems are stated in Sec. 5. For some simple examples the concept of virtual waves is introduced in Sec. 6. A virtual wave is a wave motion that satisfies appropriate conditions on the boundaries and is a solution of the elastodynamic equations. It is shown that combining the desired solution as state A with a virtual wave as state B provides explicit results for state A. Basic elastodynamic states are discussed in Sec. 7. These states play an important role in the formulation of integral representations and integral equations, as shown in Sec. 8. Reciprocity in 1-D and full-space elastodynamics are discussed in Secs. 910, respectively. Applications to a half-space and a layer are reviewed in Secs. 1112. Section 13 is concerned with reciprocity of coupled acousto-elastic systems. The paper is completed with a brief discussion of reciprocity for piezoelectric systems. There are 61 references cited in this review article.
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Norris, A. N., and A. L. Shuvalov. "Elastodynamics of radially inhomogeneous spherically anisotropic elastic materials in the Stroh formalism." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, no. 2138 (October 12, 2011): 467–84. http://dx.doi.org/10.1098/rspa.2011.0463.

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A method for solving elastodynamic problems in radially inhomogeneous elastic materials with spherical anisotropy is presented, i.e. materials having c ijkl = c ijkl ( r ) in a spherical coordinate system { r , θ , ϕ }. The time-harmonic displacement field u ( r , θ , ϕ ) is expanded in a separation of variables form with dependence on θ , ϕ described by vector spherical harmonics with r -dependent amplitudes. It is proved that such separation of variables solution is generally possible only if the spherical anisotropy is restricted to transverse isotropy (TI) with the principal axis in the radial direction, in which case the amplitudes are determined by a first-order ordinary differential system. Restricted forms of the displacement field, such as u ( r , θ ), admit this type of separation of variables solution for certain lower material symmetries. These results extend the Stroh formalism of elastodynamics in rectangular and cylindrical systems to spherical coordinates.
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Bluman, G., A. F. Cheviakov, and J. F. Ganghoffer. "Nonlocally related PDE systems for one-dimensional nonlinear elastodynamics." Journal of Engineering Mathematics 62, no. 3 (March 22, 2008): 203–21. http://dx.doi.org/10.1007/s10665-008-9221-7.

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Trainiti, G., Y. Ra'di, M. Ruzzene, and A. Alù. "Coherent virtual absorption of elastodynamic waves." Science Advances 5, no. 8 (August 2019): eaaw3255. http://dx.doi.org/10.1126/sciadv.aaw3255.

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Absorbers suppress reflection and scattering of an incident wave by dissipating its energy into heat. As material absorption goes to zero, the energy impinging on an object is necessarily transmitted or scattered away. Specific forms of temporal modulation of the impinging signal can suppress wave scattering and transmission in the transient regime, mimicking the response of a perfect absorber without relying on material loss. This virtual absorption can store energy with large efficiency in a lossless material and then release it on demand. Here, we extend this concept to elastodynamics and experimentally show that longitudinal motion can be perfectly absorbed using a lossless elastic cavity. This energy is then released symmetrically or asymmetrically by controlling the relative phase of the impinging signals. Our work opens previously unexplored pathways for elastodynamic wave control and energy storage, which may be translated to other phononic and photonic systems of technological relevance.
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Schevenels, Mattias, Stijn François, and Geert Degrande. "EDT: An ElastoDynamics Toolbox for MATLAB." Computers & Geosciences 35, no. 8 (August 2009): 1752–54. http://dx.doi.org/10.1016/j.cageo.2008.10.012.

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Weaver, R. L. "Uniqueness in elastodynamics for systems with nonlocal impedance boundary conditions." Journal of the Acoustical Society of America 100, no. 5 (November 1996): 3447–49. http://dx.doi.org/10.1121/1.416987.

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Lei, Hin-Chi, and Ming-Jui Hung. "Linearity of waves in some systems of non-linear elastodynamics." International Journal of Non-Linear Mechanics 32, no. 2 (March 1997): 353–60. http://dx.doi.org/10.1016/s0020-7462(96)00064-9.

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Perthame, Benoit, and Athanasios E. Tzavaras. "Kinetic Formulation for Systems of Two¶Conservation Laws and Elastodynamics." Archive for Rational Mechanics and Analysis 155, no. 1 (October 1, 2000): 1–48. http://dx.doi.org/10.1007/s002050000109.

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Rossi, Riccarda, and Marita Thomas. "From adhesive to brittle delamination in visco-elastodynamics." Mathematical Models and Methods in Applied Sciences 27, no. 08 (April 28, 2017): 1489–546. http://dx.doi.org/10.1142/s0218202517500257.

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In this paper, we analyze a system for brittle delamination between two visco-elastic bodies, also subject to inertia, which can be interpreted as a model for dynamic fracture. The rate-independent flow rule for the delamination parameter is coupled with the momentum balance for the displacement, including inertia. This model features a nonsmooth constraint ensuring the continuity of the displacements outside the crack set, which is marked by the support of the delamination parameter. A weak solvabi- lity concept, generalizing the notion of energetic solution for rate-independent systems to the present mixed rate-dependent/rate-independent frame, is proposed. Via refined variational convergence techniques, existence of solutions is proved by passing to the limit in approximating systems which regularize the nonsmooth constraint by conditions for adhesive contact. The presence of the inertial term requires the design of suitable recovery spaces small enough to provide compactness but large enough to recover the information on the crack set in the limit.
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Sun, Qi, Jorge Angeles, and Genliang Chen. "The Cartesian elastodynamics linear model of mechanical systems with flexible links." Mechanism and Machine Theory 167 (January 2022): 104559. http://dx.doi.org/10.1016/j.mechmachtheory.2021.104559.

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Dissertations / Theses on the topic "Elastodynamics Systems"

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Rieger, Marc Oliver. "Nonconvex Dynamical Problems." Doctoral thesis, Universitätsbibliothek Leipzig, 2004. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-37269.

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Many problems in continuum mechanics, especially in the theory of elastic materials, lead to nonlinear partial differential equations. The nonconvexity of their underlying energy potential is a challenge for mathematical analysis, since convexity plays an important role in the classical theories of existence and regularity. In the last years one main point of interest was to develop techniques to circumvent these difficulties. One approach was to use different notions of convexity like quasi-- or polyconvexity, but most of the work was done only for static (time independent) equations. In this thesis we want to make some contributions concerning existence, regularity and numerical approximation of nonconvex dynamical problems.
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Rossi, Marco. "Dynamics and stability of discrete and continuous structures: flutter instability in piecewise-smooth mechanical systems and cloaking for wave propagation in Kirchhoff plates." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/322240.

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The first part of this Thesis deals with the analysis of piecewise-smooth mechanical systems and the definition of special stability criteria in presence of non-conservative follower forces. To illustrate the peculiar stability properties of this kind of dynamical system, a reference 2 d.o.f. structure has been considered, composed of a rigid bar, with one and constrained to slide, without friction, along a curved profile, whereas the other and is subject to a follower force. In particular, the curved constraint is assumed to be composed of two circular profiles, with different and opposite curvatures, defining two separated subsystems. Due to this jump in the curvature, located at the junction point between the curved profiles, the entire mechanical structure can be modelled by discontinuous equations of motion, the differential equations valid in each subsystem can be combined, leading to the definition of a piecewise-smooth dynamical system. When a follower force acts on the structure, an unexpected and counterintuitive behaviour may occur: although the two subsystems are stable when analysed separately, the composed structure is unstable and exhibits flutter-like exponentially-growing oscillations. This special form of instability, previously known only from a mathematical point of view, has been analysed in depth from an engineering perspective, thus finding a mechanical interpretation based on the concept of non-conservative follower load. Moreover, the goal of this work is also the definition of some stability criteria that may help the design of these mechanical piecewise-smooth systems, since classical theorems cannot be used for the investigation of equilibrium configurations located at the discontinuity. In the literature, this unusual behaviour has been explained, from a mathematical perspective, through the existence of a discontinuous invariant cone in the phase space. For this reason, starting from the mechanical system described above, the existence of invariant cones in 2 d.o.f. mechanical systems is investigated through Poincaré maps. A complete theoretical analysis on piecewise-smooth dynamical systems is presented and special mathematical properties have been discovered, valid for generic 2~d.o.f. piecewise-smooth mechanical systems, which are useful for the characterisation of the stability of the equilibrium configurations. Numerical tools are implemented for the analysis of a 2~d.o.f. piecewise-smooth mechanical system, valid for piecewise-linear cases and extendible to the nonlinear ones. A numerical code has been developed, with the aim of predicting the stability of a piecewise-linear dynamical system a priori, varying the mechanical parameters. Moreover, “design maps” are produced for a given subset of the parameters space, so that a system with a desired stable or unstable behaviour can easily be designed. The aforementioned results can find applications in soft actuation or energy harvesting. In particular, in systems devoted to exploiting the flutter-like instability, the range of design parameters can be extended by using piecewise-smooth instead of smooth structures, since unstable flutter-like behaviour is possible also when each subsystem is actually stable. The second part of this Thesis deals with the numerical analysis of an elastic cloak for transient flexural waves in Kirchhoff-Love plates and the design of special metamaterials for this goal. In the literature, relevant applications of transformation elastodynamics have revealed that flexural waves in thin elastic plates can be diverted and channelled, with the aim of shielding a given region of the ambient space. However, the theoretical transformations which define the elastic properties of this “invisibility cloak” lead to the presence of a strong compressive prestress, which may be unfeasible for real applications. Moreover, this theoretical cloak must present, at the same time, high bending stiffness and a null twisting rigidity. In this Thesis, an orthotropic meta-structural plate is proposed as an approximated elastic cloak and the presence of the prestress has been neglected in order to be closer to a realistic design. With the aim of estimating the performance of this approximated cloak, a Finite Element code is implemented, based on a sub-parametric technique. The tool allows the investigation of the sensitivity of specific stiffness parameters that may be difficult to match in a real cloak design. Moreover, the Finite Element code is extended to investigate a meta-plate interacting with a Winkler foundation, to analyse how the substrate modulus transforms in the cloak region. This second topic of the Thesis may find applications in the realization of approximated invisibility cloaks, which can be employed to reduce the destructive effects of earthquakes on civil structures or to shield mechanical components from unwanted vibrations.
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Agrawal, Manish. "Efficient Simulation Strategies for Electromechanical Systems, Contact Mechanics and Time Finite Elements, within the Framework of Hybrid Finite Elements." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4228.

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The purpose of this thesis is to provide robust numerical schemes for various challenging nonlinear large-deformation elasticity problems. The presence of geometric and material nonlinearities poses interesting challenges in the numerical implementation of time finite element methods, multiphysics and contact problems, and it is the goal of this thesis to address these challenges. It is well known that displacement based elements show overstiff behavior known as ‘locking’ for a large class of practical problems with thin structures, structures with high curvature, and almost incompressible material. To alleviate the locking problem associated with displacement based elements, shell elements based on mixed formulations and hybrid elements have been proposed in the literature. However, due to the kinematic assumptions involved in the development of shell elements, the applicability of these elements is limited. Hybrid elements, based on two-field variational principle are hexahedral elements, with no kinematic assumptions involved in their development. Further, hybrid elements have been shown to provide excellent coarse mesh accuracy for a large class of problems. In this thesis, we further develop the hybrid finite element method for the following new class of problems: Developing a quadratic time finite element method for elastodynamics systems For chaotic systems, the quadratic transient time finite element strategy is significantly more efficient and robust as compared to the linear transient scheme. Motivated by this, in the first part of the thesis, we propose a quadratic time finite element strategy for large-deformation elastodynamics systems. The proposed method is a modified time finite element strategy that conserves linear and angular momenta exactly, and energy in an approximate sense, in the fully discrete setting. Further, to obtain good coarse mesh accuracy, the proposed transient strategy is extended to the hybrid element framework. Analysis of electromechanical systems Due to the strong coupling between electromagnetic and displacement fields, there is a need to develop a robust fully-coupled scheme for modeling electromechanical phenomenon. To achieve this, we present a fully-coupled monolithic numerical scheme for modeling electromechanical systems. Further, in view of the superiority of hybrid elements, we extend our monolithic formulation to the hybrid finite element framework. We perform a consistent linearization of the eddy current and structural equations in the reference configuration to ensure a quadratic rate of convergence. Contact analysis using mortar methods In the final part of the thesis, we attempt the classical problem of contact between two bodies under the large-deformation elasticity framework. We use mortar elements to satisfy the geometric constraint of non-penetrability, and provide a detailed expla-nation for using two 2-node linear elements on the edge of a 9-node two-dimensional quadrilateral element for the interpolation of the Lagrangian multiplier. We further propose a new projection technique for enhancing the accuracy of the predicted con-tact pressure. We then extend the above displacement-based formulation to the hybrid framework so as to be able to model the contact of shell-type as well as ‘chunky’ geometries efficiently. 2
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Rieger, Marc Oliver. "Nonconvex Dynamical Problems." 2002. https://ul.qucosa.de/id/qucosa%3A10949.

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Many problems in continuum mechanics, especially in the theory of elastic materials, lead to nonlinear partial differential equations. The nonconvexity of their underlying energy potential is a challenge for mathematical analysis, since convexity plays an important role in the classical theories of existence and regularity. In the last years one main point of interest was to develop techniques to circumvent these difficulties. One approach was to use different notions of convexity like quasi-- or polyconvexity, but most of the work was done only for static (time independent) equations. In this thesis we want to make some contributions concerning existence, regularity and numerical approximation of nonconvex dynamical problems.
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Mousikou, Ioanna. "Discontinuous Galerkin Method for Hyperbolic Conservation Laws." Thesis, 2016. http://hdl.handle.net/10754/621929.

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Hyperbolic conservation laws form a special class of partial differential equations. They describe phenomena that involve conserved quantities and their solutions show discontinuities which reflect the formation of shock waves. We consider one-dimensional systems of hyperbolic conservation laws and produce approximations using finite difference, finite volume and finite element methods. Due to stability issues of classical finite element methods for hyperbolic conservation laws, we study the discontinuous Galerkin method, which was recently introduced. The method involves completely discontinuous basis functions across each element and it can be considered as a combination of finite volume and finite element methods. We illustrate the implementation of discontinuous Galerkin method using Legendre polynomials, in case of scalar equations and in case of quasi-linear systems, and we review important theoretical results about stability and convergence of the method. The applications of finite volume and discontinuous Galerkin methods to linear and non-linear scalar equations, as well as to the system of elastodynamics, are exhibited.
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Book chapters on the topic "Elastodynamics Systems"

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Georgievskii, D. V. "How to Formulate the Initial-Boundary-Value Problem of Elastodynamics in Terms of Stresses?" In Continuous and Distributed Systems, 89–95. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-03146-0_7.

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Shimada, M., and Kumar K. Tamma. "Implicit Time Integrators and Designs for Nonlinear Second-Order Transient Systems: Elastodynamics." In Encyclopedia of Thermal Stresses, 2409–16. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-007-2739-7_758.

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Lara-Molina, Fabian Andres, Edson Hideki Koroishi, and Thamiris Lima Costa. "Elastodynamic Performance of a Planar Parallel Mechanism Under Uncertainties." In Multibody Mechatronic Systems, 183–92. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-67567-1_17.

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Dumitru, N., N. Craciunoiu, R. Malciu, and N. Ploscaru. "Elastodynamic Analysis of the Sucker Rod Pumping System Mechanism." In New Trends in Mechanism and Machine Science, 355–63. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09411-3_38.

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Liu, Hongwei, Pooneh Maghoul, and Ahmed Shalaby. "A Poro-elastodynamic Forward Solver for Dispersion Analysis of Saturated Multilayer Systems." In Challenges and Innovations in Geomechanics, 637–44. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-64518-2_75.

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"Reciprocity for piezoelectric systems." In Reciprocity in Elastodynamics, 233–46. Cambridge University Press, 2004. http://dx.doi.org/10.1017/cbo9780511550485.015.

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"Reciprocity for coupled acousto-elastic systems." In Reciprocity in Elastodynamics, 220–32. Cambridge University Press, 2004. http://dx.doi.org/10.1017/cbo9780511550485.014.

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Kitahara, M., and K. Nakagawa. "ELASTODYNAMICS (2D): APPLICATIONS OF A BOUNDARY ELEMENT PROGRAM." In Structural Analysis Systems, 51–64. Elsevier, 1986. http://dx.doi.org/10.1016/b978-0-08-032582-8.50012-9.

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BOSTRÖM, ANDERS. "ON THE SYSTEMATIC USE OF SPHERICAL, CYLINDRICAL AND PLANE: VECTOR WAVE FUNCTIONS IN ELASTODYNAMIC SCATTERING PROBLEMS." In Series on Stability, Vibration and Control of Systems, Series B, 41–79. WORLD SCIENTIFIC, 2002. http://dx.doi.org/10.1142/9789812778536_0002.

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Conference papers on the topic "Elastodynamics Systems"

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Valtchev, Svilen S., and Nuno F. M. Martins. "Meshfree Approximate Solution of the Cauchy– Navier Equations of Elastodynamics." In 2021 3rd International Conference on Control Systems, Mathematical Modeling, Automation and Energy Efficiency (SUMMA). IEEE, 2021. http://dx.doi.org/10.1109/summa53307.2021.9632193.

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Bagci, Cemil, and Siva K. Rajavenkateswaran. "Dynamic Response of Multi-Cylinder Engines As Spatial Elastic Linkage Systems." In ASME 1996 Design Engineering Technical Conferences and Computers in Engineering Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-detc/mech-1183.

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Abstract Dynamics of multi-cylinder engines have been performed by the conventional methods using lumped pure torsional systems. This article offers a finite element method of performing elastodynamic analysis of multi-cylinder engines considering them as spatial linkage systems with true spatial geometries of the crankshaft and the linkage loops. An engine can have any number of cylinders with linear offsets and angular orientations relative to each other. A three-dimensional finite-line element with isoparametric joint irregularity freedoms is developed and used. Consistent or lumped mass systems can be used. Elastodynamics of engines is considered in two forms: (a) kinetoelastostatics (KES) where all forces and torques acting on the system are considered except the vibratory motion effect; (b) kinetoelastodynamics (KED) where the forced and damped equations of motion of the system are solved. Matrix exponential method of solving equations of KED motions are presented and used. It is proven to be a very efficient and stable technique for the solutions of large systems of linear and nonlinear differential equations of any order. After solving for the generalized coordinates, time histories of the neutral coordinate displacements, forces, moments, stresses, bearing forces, and generated torque are determined for as many work cycles as desired. A generalized computer program performing KED and KES studies of any multi-cylinder engine is made available for industrial use. KED and KES analyses of a four-cylinder automobile engine are performed.
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Hernandez, J. A., and T. N. Tallman. "The Piezoresistive Response of CNF/Epoxy to One-Dimensional Strain Wave Excitation via Remote Loading." In ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/smasis2020-2250.

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Abstract The piezoresistive effect in conductive nanofiller-modified polymer, cementitious, and ceramic composites has immense potential to enable multifunctional properties such as intrinsic self-sensing. To date, much work has been done to study the piezoresistive effect under quasi-static loading. Some work has also been done to study the piezoresistive effect under cyclic loading such as when a piezoresistive patch is adhered directly to an oscillating substrate. However, little-to-no work has been done with regard to general dynamic loading conditions such as strain waves originating from a remote source. This is an important gap in the state of the art for two reasons: One, coupling the self-sensing nature of nanocomposites with general elastodynamics is a possible pathway to enabling the study of full-field dynamics (i.e. using the piezoresistive effect to study internal dynamics as opposed to just surface measurements available via tools such as accelerometers and laser vibrometry). And two, coupling piezoresistive self-sensing with damage detection via vibratory methods could lead to transformative gains in the areas of structural health monitoring (SHM) and nondestructive evaluation (NDE). Therefore, we herein work towards addressing this gap in the state of the art by developing basic knowledge on the relation between elastic strain waves and piezoresistive response. Specifically, an electromagnetic-piezoelectric shaker is used to inject highly-controlled strain waves into a long and slender carbon nanofiber (CNF)-modified epoxy rod. Resistance changes along the length of the rod are then measured as strain waves travel along the length of the rod. It is shown that the measured resistance response closely matches the applied mechanical loading. Results from this preliminary study suggest the establishment of an exciting new field — piezoresistive elastodynamics.
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Hernandez, J. A., H. Zhu, F. Semperlotti, and T. N. Tallman. "The Transient Response of Piezoresistive CNF-Modified Epoxy Rods to One-Dimensional Wave Packet Excitation." In ASME 2021 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/smasis2021-67801.

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Abstract Introducing conductive nanofillers into polymeric, cementitious, and ceramic composites can impart multifunctional properties such as self-sensing capabilities via the piezoresistive effect. Much work has been done to utilize this multifunctionality for conductivity-based structural health monitoring (SHM) and condition monitoring. To date, the majority of such investigations concern static and quasi-static loading conditions. Much less work has been done with regard to general dynamic loading conditions such as transient wave propagation. This is an important gap in state of the art for two reasons: First, the self-sensing nature of these materials potentially allows for full-field (i.e. sub-surface) dynamics monitoring which cannot be achieved via traditional surface-mounted dynamic sensors. And second, conductivity-based and vibratory-based SHM are both independently well researched areas. Combined into a single, piezoresistive elastodynamic formulation, however, they may give rise to unprecedented new diagnostic capabilities. Therefore, the initial results presented in this manuscript seek to address this gap in the state of the art by experimentally exploring the role of dynamic excitation on transient piezoresistive behavior in nanocomposite structures. Specifically, an electromagnetic shaker is used to inject highly-controlled planar strain wave packets into a slender prismatic carbon nanofiber (CNF)-modified epoxy rod. Resistance measurements are then taken as the wave packets travel along the length of the rod. It was found that resistance changes taken from the rod are able to accurately reconstruct the injected strain wave and can be used to discern dynamic properties of CNF-modified epoxy. An external laser vibrometry (LV) system was used as extrinsic validation. Results from this preliminary investigation may lay the foundation for a new exciting field of fully coupled piezoresistive elastodynamics.
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Moura, Adriane, and Alper Erturk. "A Distributed-Parameter Flexoelectric Energy Harvester Model Accounting for Two-Way Coupling and Size Effects." In ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/smasis2016-9254.

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We present a distributed-parameter electromechanical model and its modal analysis for flexoelectric energy harvesting using centrosymmetric dielectrics by accounting for both the direct and converse effects as well as size dependence of the coupling coefficient. Flexoelectricity is the generation of electric polarization in elastic dielectrics by the application of a non-uniform mechanical strain field, i.e. a strain gradient. In order to accompany atomistic simulations and experimental efforts at small scales, there is a growing need for high-fidelity device models that can also provide an analytical insight into size-dependent electro-elastodynamics of small structures that exhibit and exploit flexoelectricity. Particularly, although the conversion of mechanical energy into electrical energy (i.e. energy harvesting) is more related to the direct effect, it is necessary to accurately model the converse effect for thermodynamic consistency and completeness. To this end, we present a flexoelectric monolayer centrosymmetric energy harvester model (that yields no piezoelectric effect) for converting ambient vibration into electricity. The flexoelectric energy harvester model based on the Euler-Bernoulli beam theory is focused on strain gradient-induced polarization resulting from the bending (transverse) vibration modes in response to mechanical base excitation. Following recent efforts on the converse flexoelectric effect in finite samples, the proposed model accounts for two-way coupling, i.e. the direct and converse effects, and it also captures the effect of geometric scaling on the coupling coefficient. In addition to closed-form solutions of the electromechanical frequency response functions, various case studies are presented for a broad range of material and geometric parameters. Thickness dependence of the electromechanical coupling is analytically shown and is observed in simulations of the electromechanical frequency response functions as well.
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Mucchi, Emiliano, and Giorgio Dalpiaz. "Experimental Validation of a Model for the Dynamic Analysis of Gear Pumps." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12438.

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This paper concerns the experimental validation of an elastodynamic model of an external gear pump for steering systems in vehicles. The elastodynamic model takes into account the most important phenomena involved in the operation of this kind of machines. Two main sources of noise and vibration can be considered: pressure and gear meshing. An experimental apparatus has been set up for the measurements of the case accelerations and force components in operational conditions. The model was validated by comparison between simulations and experimental results concerning forces and moments: it deals with the external and inertia components acting on the gears, estimated by the model, and the reactions and inertia components on the pump case and the test plate, obtained by measurements. The validation is carried out comparing the level of the time synchronous average in the time domain and the waterfall maps in the frequency domain, with particular attention to identify system resonances. The validation results are globally satisfactory.
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Zhang Zhifei and Yao Pengfei. "Stabilization of the nonlinear elastodynamic system with a boundary dissipation." In 2008 Chinese Control Conference (CCC). IEEE, 2008. http://dx.doi.org/10.1109/chicc.2008.4604943.

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Choi, S. B., F. Sun, M. V. Gandhi, and B. S. Thompson. "An Experimental Investigation of the Static and Elastodynamic Responses of an Industrial Robotic Manipulator." In ASME 1987 Design Technology Conferences. American Society of Mechanical Engineers, 1987. http://dx.doi.org/10.1115/detc1987-0107.

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Abstract A methodology is presented herein for experimentally evaluating the static and elastodynamic responses of industrial robotic manipulators. The procedure enables estimates of the principal characteristics of these machines to be quantified in order to identify limitations in the structural elements of these designs. Furthermore, the proposed approach also provides experimental data with which to evaluate the predictive capabilities of the various mathematical models proposed in the literature for predicting the static and elastodynamic behavior of these systems. In order to demonstrate the test procedure, a General Electric Company P50 articulating robot was subjected to evaluation, the error sources identified and the associated errors quantified.
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Ghaith, Fadi A., and Ahmad Ayub. "Elastodynamic Modeling and Simulation of an Axially Accelerating Beam." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-46644.

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This paper aims to develop an accurate nonlinear mathematical model which may describe the coupled in-plane motion of an axially accelerating beam. The Extended Hamilton’s Principle was utilized to derive the partial differential equations governing the motion of a simply supported beam. The set of the ordinary differential equations were obtained by means of the assumed mode method. The derived elastodynamic model took into account the geometric non-linearity, the time-dependent axial velocity and the coupling between the transverse and longitudinal vibrations. The developed equations were solved numerically using the Runge-Kutta method and the obtained results were presented in terms of the vibrational response graphs and the system natural frequencies. The system dynamic characteristics were explored with a major focus on the influence of the velocity, acceleration and the excitation force frequency. The obtained results showed that the natural frequency decreased significantly at high axial velocities. Also it was found that the system may exhibit unstable behavior at high accelerations.
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10

Gandhi, M. V., B. S. Thompson, and S. Shakir. "Electro-Rheological-Fluid-Based Articulating Robotic Systems." In ASME 1987 Design Technology Conferences. American Society of Mechanical Engineers, 1987. http://dx.doi.org/10.1115/detc1987-0056.

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Abstract The limitations of the current generation of robotic systems has triggered a new research thrust for predicting the elastodynamic response of assemblages of articulating flexible-bodied systems. This research thrust is extended herein by proposing the fabrication of robotic systems in either monolithic or ultra-advanced composite laminated high-strength, high-stiffness materials in which are incorporated electrorheological fluids. These multi-phase fluid systems, which change their rheological behavior instantaneously when subjected to an externally applied electrical field, provide a potential for tailoring the vibrational characteristics of these hybrid materials from which the structural members of the proposed robotic systems are fabricated. This paper is focused on developing the necessary design tools for predicting the vibrational response of flexible multibodied articulating systems fabricated with this new class of advanced materials. A variational theorem is developed herein as a basis for finite element formulations which can be employed to predict the elastodynamic response of these systems. A coherent combination of experimental and theoretical work on cantilevered beams is presented to demonstrate the viability of the proposed design methodology. In addition, computer simulation results are presented to demonstrate the potential payoffs in terms of superior performance characteristics of a new generation of robotic systems capitalizing on this innovative and revolutionary design philosophy.
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Reports on the topic "Elastodynamics Systems"

1

Armero, Francisco. Numerical Analysis of Constrained Dynamical Systems, with Applications to Dynamic Contact of Solids, Nonlinear Elastodynamics and Fluid-Structure Interactions. Fort Belvoir, VA: Defense Technical Information Center, December 2000. http://dx.doi.org/10.21236/ada387568.

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