Showing papers on "Newmark-beta method published in 2014"
TL;DR: In this article, a hybrid heuristic optimization strategy is presented to simultaneously identify structural parameters and, when possible, dynamic input time histories from incomplete sets of output measurements, combining a swarm intelligence algorithm, the artificial bee colony algorithm, with a local search operator, Nelder-Mead simplex method, integrated in a search space reduction approach, so as to improve the convergence efficiency of the overall identification process.
Abstract: SUMMARY
A hybrid heuristic optimization strategy is presented to simultaneously identify structural parameters and, when possible, dynamic input time histories from incomplete sets of output measurements. The proposed strategy combines a novel swarm intelligence algorithm, the artificial bee colony algorithm, with a local search operator, Nelder–Mead simplex method, integrated in a search space reduction approach, so as to improve the convergence efficiency of the overall identification process. Because of the independent nature of the algorithm, a parallel scheme is implemented so as to improve the computational efficiency. If the time histories of the structural response and information about the mass of the structural system are available, then the algorithm can also be used for the identification of the time histories of the dynamic input force through a modified Newmark integration scheme, using the current estimates of the structural parameters. To investigate the applicability of the proposed technique, three numerical examples, two shear-type building models and a coupled building system model under different conditions of data availabilities and noise corruption levels are presented. The results show that the proposed technique is powerful, robust and efficient in the simultaneous identification of the structural parameters and input force even from an incomplete set of noise-contaminated structural response measurements. Copyright © 2013 John Wiley & Sons, Ltd.
74 citations
TL;DR: In this article, a three-dimensional model of a two-stage straight bevel gear system is presented, and the dynamic response is calculated using Newmark method which is step-by-step time integration.
62 citations
TL;DR: In this paper, a real-time hybrid simulation (RTHS) system for efficient dynamic testing of high voltage electrical vertical-break disconnect switches is presented, which consists of the computational model of the support structure, the physical model of an insulator post, a small shaking table, a state-of-the-art controller, a data acquisition system and a digital signal processor.
Abstract: SUMMARY
This paper presents the development and validation of a real-time hybrid simulation (RTHS) system for efficient dynamic testing of high voltage electrical vertical-break disconnect switches. The RTHS system consists of the computational model of the support structure, the physical model of the insulator post, a small shaking table, a state-of-the-art controller, a data acquisition system and a digital signal processor. Explicit Newmark method is adopted for the numerical integration of the governing equations of motion of the hybrid structure, which consists of an insulator post (experimental substructure) and a spring-mass-dashpot system representing the support structure (analytical substructure). Two of the unique features of the developed RTHS system are the application of an efficient feed-forward error compensation scheme and the ability to use integration time steps as small as 1 ms. After the development stage, proper implementation of the algorithm and robustness of the measurements used in the calculations are verified. The developed RTHS system is further validated by comparing the RTHS test results with those from a conventional shaking table test. A companion paper presents and discusses a parametric study for a variety of geometrical and material configurations of these switches using the developed RTHS system. Copyright © 2013 John Wiley & Sons, Ltd.
62 citations
TL;DR: In this article, the beam response can be determined reliably via an optimal statistical linearization procedure, which is obtained by utilizing an appropriate iterative representation of the stochastic response spectrum, which involves the linear modes of vibration of the beam.
Abstract: This paper deals with nonlinear random vibrations of a beam comprising a fractional derivative element; the nonlinear term arises from the assumption of moderately large beam displacements. It is shown that the beam response can be determined reliably via an optimal statistical linearization procedure. Specifically, the solution is obtained by utilizing an appropriate iterative representation of the stochastic response spectrum, which involves the linear modes of vibration of the beam. Such a representation allows retaining the nonlinearity in the time-dependent part of the response, which, in turn, is linearized in a stochastic mean square sense. The reliability of the proposed approximate solution is assessed in relation to the results of relevant Monte Carlo simulations. In this regard, a boundary integral method (BIM)–based algorithm is employed, in conjunction with a Newmark integration scheme, for estimating the beam response from spectrum-compatible realizations of the excitation, while acc...
49 citations
TL;DR: In this article, the authors present the development and use of a novel and promising numerical scheme, the method of finite spheres, for the analysis of wave propagations, which does not require a mesh and hence avoids element distortions.
39 citations
TL;DR: In this paper, the authors extend the Newmark method from viscously damped structure systems to nonviscous damped structures and derive an analysis method based on Newmark's assumption of acceleration, where the convolution integral term is calculated directly using the trapezoidal rule.
Abstract: Nonviscous damping models in which the damping forces depend on the history of velocities via convolution integrals over some kernel functions have risen in many different subjects. The aim of this paper is to extend the Newmark method from viscously damped structure systems to nonviscously damped structure systems. The proposed analysis method for nonviscously damped structure systems is derived based on Newmark’s assumption of acceleration. The convolution integral term is calculated directly using the trapezoidal rule. The computational procedure of the proposed direct time integration method for nonviscously damped structure systems is given in detail. Finally, the dynamic responses of two nonviscously damped structure systems are computed using the proposed method. The accuracy and efficiency of the proposed method are discussed through comparison with another developed method.
34 citations
TL;DR: Bellman’s Principle of Optimality is used for the minimization of the objective function to estimate the excitation forces and the dynamic programming method of identification formulations is deduced.
31 citations
TL;DR: A development of HONMM to achieve a dynamic solution with high accuracy and less computational cost is addressed and the superiority of the proposed method over the conventional NMM is demonstrated through a special beam example.
Abstract: High Order Numerical Manifold Method (HONMM) is a powerful method to solve static problems. A development of HONMM to achieve a dynamic solution with high accuracy and less computational cost is addressed in the current paper. In the developed method, the global approximation is obtained through increasing the order of local approximation functions without any Linear Dependence (LD) of the unknowns. The weighted residual formulations are modified to be used in dynamic high order simulation. Moreover, a modified Newmark method formulation is adjusted for time integration of high order equations. The superiority of the proposed method over the conventional NMM is demonstrated through a special beam example. The dynamic free fall block example is used to exhibit the removal of mass matrix singularity. As cases of dynamic analysis, beam free and forced vibrations are illustrated which include a moving load. Finally, a non‐uniform cross‐section beam under dynamic variable loads with accelerated motion is solved while demonstrating the capability of the new method such as simplicity, accuracy and time efficiency for simulation of complex dynamic problems. Copyright © 2014 John Wiley & Sons, Ltd.
30 citations
Abstract: A direct time integration method is presented for the solution of the equations of motion describing the dynamic response of structural linear and nonlinear multi-degree-of-freedom systems. It applies also to large systems of second order differential equations with fully populated, non symmetric coefficient matrices as well as to equations with variable coefficients. The proposed method is based on the concept of the analog equation, which converts the coupled N equations into a set of single term uncoupled second order ordinary quasi-static differential equations under appropriate fictitious loads, unknown in the first instance. The fictitious loads are established from the integral representation of the solution of the substitute single term equations. The method is simple to implement. It is self starting, unconditionally stable and accurate and conserves energy. It performs well when large deformations and long time durations are considered and it can be used as a practical method for integration of the equations of motion in cases where widely used time integration procedures, e.g. Newmark's, become unstable. Several examples are presented, which demonstrate the efficiency of the method. The method can be straightforward extended to evolution equations of order higher than two.
27 citations
17 Dec 2014
TL;DR: A gear dynamic model including localized tooth defect has been developed and it is shown that the kurtosis of the vibration signal is a sensitive indicator of the existence of damage in the gear pair.
Abstract: Gear mechanisms are an important element in a variety of mechanical systems, such as industrial machinery and automotive Health monitoring of rotating machines is important to avoid failure of the system in advance Principally, this paper consists of two parts: in the first part, a gear dynamic model including localized tooth defect has been developed The model consists of a spur gear pair, two inertias The model incorporates the effects of time-varying mesh stiffness and damping, excitation due to gear errors The results of a dynamic modeling of the gears transmission are calculated by using the Newmark integration scheme The second part consists of signal processing of simulated and experimental signals using the wavelet transform It is shown that the kurtosis of the vibration signal is a sensitive indicator of the existence of damage in the gear pair
25 citations
TL;DR: In this paper, a cross weighted residual (CWR) time integration scheme is proposed to solve the structural dynamics problems in terms of displacements and velocities, where each of the two residuals takes the other one as a weight function in the minimization.
Abstract: In this article, we develop a novel stable time integration scheme for the transient analysis of structural dynamics problems. A second-order (in time) differential operator equation (e.g. obtained after finite element discretization in space) is written as a pair of first-order equations in terms of displacements and velocities. Then the solution is sought by minimizing the inner product of the residuals in the two equations (an unconventional approach) over typical time interval to obtain a symmetric set of algebraic equations involving displacements and velocities at two subsequent intervals. The new time integration scheme is termed the cross weighted-residual (CWR) time integration scheme because each of the two residuals takes the other one as a weight function in the minimization. The CWR time integration scheme is developed by using a uniform linear time approximation of the displacement and velocity fields to yield only a single step time integration scheme, which is comparable to the Newmark family of time integration scheme. A reduced integration technique is used to prevent velocity locking, which is caused by linear approximation of both the displacement and velocity fields. For the verification of the consistency and the stability, the CWR time integration scheme is tested with single-degree as well as multi-degree of freedom problems. The scheme performs extremely well compared with those of the well-known Newmark family of time integration schemes.
TL;DR: In this article, a variational formulation is derived by using the Reissner-Mindlin first-order shear deformation (FOSD) hypothesis and full geometrically nonlinear strain-displacement relations accounting for finite rotations.
Abstract: This paper deals with static and dynamic analysis of thin-walled structures with integrated piezoelectric layers as sensors and actuators in the geometrically nonlinear range of deformations. A variational formulation is derived by using the Reissner–Mindlin first-order shear deformation (FOSD) hypothesis and full geometrically nonlinear strain-displacement relations accounting for finite rotations. The finite rotations are treated by Rodriguez parameterization. In order to enhance the accuracy of a four-node shell element, a combination of an assumed natural strain (ANS) method for the shear strains, an enhanced assumed strain (EAS) method for the membrane strains and an enhanced assumed gradient (EAG) method for the electric field are employed. The present shell element has five mechanical degrees of freedom (DOFs) and three electrical DOFs per node. The Newton–Raphson method for static analysis and the Newmark method for dynamic analysis are used to perform linear and nonlinear simulations. In comparison to the results obtained by simplified nonlinear models reported in the existing literature, the finite-element simulations performed in this paper show the importance of the present model, precisely for structures undergoing finite deformations and rotations.
7 Jan 2014
TL;DR: In this paper, a dynamic numerical solution for deflections of curved beam structures is proposed, in which a prismatic semicircular arch with uniform cross section, in various boundary conditions, is assumed.
Abstract: The present study proposes a dynamic numerical solution for deflections of curved beam structures. In order to extract characteristic equations of an arch under an in-plane constant moving load, an analysis procedure based on the Euler–Bernoulli beam theory considering polar system is conducted. A prismatic semicircular arch with uniform cross section, in various boundary conditions, is assumed. Radial and tangential displacements, as well as bending moments are obtained using differential quadrature method as a well-known numerical method. In addition to parametric studies, a curved steel bridge as an actual application is analyzed by the mentioned method. By using this differential quadrature technique, the function values and some partial derivatives are approximated by weighting coefficients. Convergence study is carried out to demonstrate the stability of the present method. In order to confirm the high level of accuracy of this approach, some comparisons are made between the results obtained by sele...
TL;DR: In this article, a numerical method based on B-spline was developed to solve the time-dependent Emden-Fow-Ler-type equations, and the error analysis of the method was described.
Abstract: A numerical method based on B-spline is
developed to solve the time-dependent Emden-Fow- ler-type equations. We also present a reliable
new algorithm based on B-spline to overcome the difficulty of the singular
point at x = 0. The error analysis of the method is described. Numerical results are
given to illustrate the efficiency of the proposed method.
TL;DR: In this paper, the dynamic responses of a riser under the combined excitation of internal waves and background currents are studied, and a modified Taylor-Goldstein equation is used to calculate the internal waves vertical structures when background currents exist.
TL;DR: In this paper, the stability of a rotor bearing system with two unbalanced disks is analyzed based on a multi-degree of freedom (M-DOF) finite element model, where nonlinear effects of supporting oil-film and inertia distributions as well as shearing effect are taken into account.
Abstract: The stability of periodic motion of a rotor-bearing system with two unbalanced disks is analyzed based on a multi-degree of freedom (M-DOF) finite element model. Nonlinear effects of supporting oil-film and inertia distributions as well as shearing effect are taken into account. Focusing on the more realistic FE method to study the stability of nonlinear rotor-bearing system with the influence of the eccentricity phase, the stability calculation of the M-DOF FE model is done by using the combination of Shooting method and Newmark method. Experiments with a rotor-bearing test rig (two disks on a shaft with two bearings) are then performed and results are presented. It is found that typical instability characteristic is successfully produced. Through comparisons between calculated results and measurements, it is shown that the combination of Shooting method and Newmark method in studying the M-DOF rotor-bearing system is useful, especially for the complex rotor-bearing system. In addition, altering eccentricity phase of the two disks can significantly influence instability type and speed. When the two disks are out of phase, the occurring of oil whip is restrained effectively. It is suggested that a careful examination should be made in modeling more complex non-linear rotor-bearing system. Some response curves are shown to compare the beam motions at different load velocities.
TL;DR: In this paper, a hybrid formulation was developed for the simulation of scalar wave motion in two-dimensional Perfectly-Matched-Layers (PML)truncated domains.
Abstract: This paper presents a new formulation for forward scalar wave simulations in semi-infinite media. Perfectly-Matched-Layers (PMLs) are used as a wave absorbing boundary layer to surround a finite computational domain truncated from the semi-infinite domain. In this work, a hybrid formulation was developed for the simulation of scalar wave motion in two-dimensional PML-truncated domains. In this formulation, displacements and stresses are considered as unknowns in the PML domain, while only displacements are considered to be unknowns in the interior domain. This formulation reduces computational cost compared to fully-mixed formulations. To obtain governing wave equations in the PML region, complex coordinate stretching transformation was introduced to equilibrium, constitutive, and compatibility equations in the frequency domain. Then, equations were converted back to the time-domain using the inverse Fourier transform. The resulting equations are mixed (contain both displacements and stresses), and are coupled with the displacement-only equation in the regular domain. The Newmark method
was used for the time integration of the semi-discrete equations.
TL;DR: In this paper, a finite element formulation for the seismic response of damped structural systems is presented, in which the response of a cantilever beam with free layer damping is analyzed.
Abstract: This paper presents a finite element formulation for the seismic response of damped structural systems. Damping is obtained using a viscoelastic material, which is characterized by a constitutive law with fractional derivatives. The weighted residue method is applied resulting in a fractional motion equation, which is numerically integrated through an implicit scheme in combination with the constant acceleration Newmark method. An example of application is presented, in which the response of a cantilever beam with free layer damping is analyzed. The material properties are identified from the material experimental characterization, where the parameters of the fractional model were identified by curve fitting. The results of the simulation are compared with the experimental ones, concluding that the tendencies observed in the measurements are reproduced.
TL;DR: Based on the von Karman equation and classical thin plate theory, thermomechanical behavior of a high strength low alloy (HSLA) steel circular plate under impact load is investigated in this article.
Abstract: Based on the von Karman equation and classical thin plate theory, thermomechanical behavior of a high strength low alloy (HSLA) steel circular plate under impact load is investigated. Firstly, when the HSLA steel circular plate is impacted by a rigid impactor, the relation of the contact radius and the instantaneous relative displacement is obtained by using the modified nonlinear Hertzian contact law, and the contact force is solved by using the time increment method. Secondly, the nonlinear governing equations in the form of displacements for the HSLA steel circular plate under the impact load are obtained by using the Hamilton variational principle. Finally, the unknown variable functions are discretized in space and time domains by utilizing the finite difference method and Newmark method, and the whole problem is solved by the iterative method. Numerical results denote that the geometrical parameters, boundary conditions of the HSLA steel circular plate and the initial velocity of impactor have great influences on deformation, the contact force and stresses of the HSLA steel circular plate.
TL;DR: In this work, smoothed meshfree methods are employed for the time-domain analysis of porous media, based on the u-p formulation where the unknown fields of the coupled analysis are the solid skeleton displacements and the interstitial fluid pore pressures.
Abstract: In this work, smoothed meshfree methods are employed for the time-domain analysis of porous media. A weakened weak formulation based on the edges of triangular cells obtained by a Delaunay triangulation is considered here, framing the so-called edge-based smoothed domains. The meshfree shape functions are computed by the radial point interpolation method considering the T3 and T6 schemes for the shape function support domains. For the time discretization, the generalized Newmark method is adopted. The work is based on the u-p formulation where the unknown fields of the coupled analysis are the solid skeleton displacements and the interstitial fluid pore pressures. An independent spatial discretization is considered for each phase of the model, rendering a more flexible and effective methodology. At the end of the paper, numerical applications illustrate the accuracy and abilities of the proposed techniques.
TL;DR: In this article, a geometrically exact finite element model for two-dimensional dynamic analysis of armored cable is presented, which accounts for the geometric nonlinearities of large displacement of the armored cable, and effects of axial load and bending stiffness.
Abstract: The armored cable used in a deep-sea remotely operated vehicle (ROV) may undergo large displacement motion when subjected to dynamic actions of ship heave motion and ocean current. A novel geometrically exact finite element model for two-dimensional dynamic analysis of armored cable is presented. This model accounts for the geometric nonlinearities of large displacement of the armored cable, and effects of axial load and bending stiffness. The governing equations are derived by consistent linearization and finite element discretization of the total weak form of the armored cable system, and solved by the Newmark time integration method. To make the solution procedure avoid falling into the local extreme points, a simple adaptive stepping strategy is proposed. The presented model is validated via actual measured data. Results for dynamic configurations, motion and tension of both ends of the armored cable, and resonance-zone are presented for two numerical cases, including the dynamic analysis under the case of only ship heave motion and the case of joint action of ship heave motion and ocean current. The dynamics analysis can provide important reference for the design or product selection of the armored cable in a deep-sea ROV system so as to improve the safety of its marine operation under the sea state of 4 or above.
TL;DR: In this article, a new analysis scheme is proposed which incorporates interaction between vehicle and expansion joint in order to precisely understand behavior of expansion joint under vehicle impact loading, and the analysis indicates that vehicle loading can induce large dynamic response of expansion joints in long span bridges.
Abstract: Due to increasing traffic on long span bridges, behavior of expansion joints is believed to be largely influenced by pounding impact from passing vehicles. In order to precisely understand behavior of expansion joint under vehicle impact loading, a new analysis scheme is proposed which incorporates interaction between vehicle and expansion joint. Mathematical model of vehicle is established and solved with Newmark method. Expansion joint is modeled with refined solid element in Finite element software ABAQUS. The analysis indicates that vehicle loading can induce large dynamic response of expansion joint in long span bridges.
TL;DR: In this paper, the analysis of vibrations and transient responses of a hollow cylinder made of functionally graded materials (FGMs) under a radially symmetric dynamic load is presented, where the material of the FGM hollow cylinder is assumed to be isotropic with constant Poisson's ratio, exponentially varying elastic modulus, and exponentially varying density through the radial thickness.
Abstract: In this article, analysis of vibrations and transient responses of a hollow cylinder made of functionally graded materials (FGMs) under a radially symmetric dynamic load is presented. The material of the FGM hollow cylinder is assumed to be isotropic with constant Poisson's ratio, exponentially-varying elastic modulus, and exponentially-varying density through the radial thickness. By means of the finite difference method and Newmark method, the governing equation of the FGM hollow cylinder under dynamic loads is solved. As numerical examples, the FGM hollow cylinder under impulsive load and that under sinusoidally varying dynamic load are discussed, and then many valuable characteristics are revealed.
1 Jan 2014
TL;DR: A feasibility study and a detailed performance evaluation of the high-frequency electromagnetic field analysis using the numerical human model on a super computer constituting Japan’s High Performance Computing Infrastructure (HPCI) as a numerical simulation infrastructure are performed.
Abstract: This paper describes large-scale full-wave analyses of electromagnetic fields using numerical human body models. This is achieved by the use of the parallel finite element method with iterative domain decomposition. Numerical examples of FDTD analysis using numerical human model by a High Performance Computing (HPC) are shown in previous researches. However, numerical examples and performance evaluation of the finite element method hardly exists. Therefore, we perform a feasibility study and a detailed performance evaluation of the high-frequency electromagnetic field analysis using the numerical human model on a super computer constituting Japan’s High Performance Computing Infrastructure (HPCI) as a numerical simulation infrastructure so as to extract problems for advancement of the future analysis. The numerical human body models provided by the National Institute of Information and Communications Technology (NICT) in Japan are composed of voxel data with all sides of 2mm and include skin layers, blood vessels, bones, internal organs, etc. distinguished by material properties. By using HPC, the user can evaluate the electromagnetic filed distribution inside the whole body model.
1 Feb 2014
TL;DR: The accuracy and stability of the proposed algorithm are successfully verified through the comparison with the analytical solutions and the Element-Free Galerkin method results.
Abstract: This paper presents a dynamic crack propagation algorithm based on the Moving Least Squares(MLS) difference method. The derivative approximation for the MLS difference method is derived by Taylor expansion and moving least squares procedure. The method can analyze dynamic crack problems using only node model, which is completely free from the constraint of grid or mesh structure. The dynamic equilibrium equation is integrated by the Newmark method. When a crack propagates, the MLS difference method does not need the reconstruction of mode model at every time step, instead, partial revision of nodal arrangement near the new crack tip is carried out. A crack is modeled by the visibility criterion and dynamic energy release rate is evaluated to decide the onset of crack growth together with the corresponding growth angle. Mode I and mixed mode crack propagation problems are numerically simulated and the accuracy and stability of the proposed algorithm are successfully verified through the comparison with the analytical solutions and the Element-Free Galerkin method results.
TL;DR: Dynamic reliability analysis of a filtering reducer is performed by accounting for discrete shocks from the space environment, using the Newmark method to resolve differential equations and the Simulink tool for the outputs.
Abstract: Dynamic reliability analysis of a filtering reducer is performed by accounting for discrete shocks from the space environment. Gears are considered as the lumped mass and meanwhile the meshing between different gears is equivalent to a dynamic system consisting of springs and dampers during construction of the dynamic model. The Newmark method is employed to resolve differential equations, and then the additional acceleration could be obtained, caused by shocks to the filtering reducer. Dynamic reliability analysis is conducted with the help of the Simulink tool for the outputs. The results are hopefully useful for spacecraft mechanism design.
TL;DR: Average and jump operators of the discontinuous Galerkin method are used to establish a domain decomposition framework for the vector generalized finite-element method such that they enable application of vector generalized infinite-element methods to inhomogeneous problems without using additional basis functions at material interfaces.
Abstract: In this article, a hybrid vector generalized finite-element method is developed for time-domain electromagnetic analysis. Average and jump operators of the discontinuous Galerkin method are used to establish a domain decomposition framework for the vector generalized finite-element method such that they enable application of vector generalized finite-element methods to inhomogeneous problems without using additional basis functions at material interfaces. Moreover, they enable hybridization of the classical finite-element method and vector generalized finite-element method such that advantages of each method can be exploited for more accurate computation of electromagnetic fields. In this article, the interior penalty discontinuous Galerkin method is used to enable communication among partitioned domains. Convergence characteristics of these hybrid methods are studied, and their applications to wave scattering problems are presented.
Journal Article•
TL;DR: In this paper, a linear transverse parametric vibration model of axially moving string was setup with fixed length and inhomogeneous boundary conditions, and the Galerkin method was applied to discretize the dynamic governing equations.
Abstract: According to application characteristics of the multi-rope friction hoisting catenaries, a linear transverse parametric vibration model of axially moving string was setup with fixed length and inhomogeneous boundary conditions. The Galerkin method was applied to discretize the dynamic governing equations. Using the Newmark method, the coupling coefficient second-order ODEs were solved. The parametric resonance vibrations of catenaries generated by tension variation along with forced boundary excitations were diagnosed with analytical and experimental validations. The transverse vibration amplitudes and frequencies of catenaries measured and analyzed by non-contact video gauge method were consistent with simulation outputs. The simulation outputs were based on practically measured parameters such as boundary displacement excitations and tension variations. The research results indicated that tension imbalance distributions of the catenaries could change their natural frequencies and result in transverse resonance under boundary harmonic displacement excitations. Therefore specific measures should be provided to maintain tension balance in multi-rope hoisting applications.
1 Jan 2014
TL;DR: In this article, the authors transformed the axial vibration mathematical model of the fluid conveying pipe, which considerate the fluid solid coupling to the beam element model for two nodes, using Lagrangian interpolation function, the first order Hermit interpolation functions and the Ritz method to obtain the element standard equation, and then integrated a global matrix equation, obtained the response of conveying fluid pipe with the Newmark method and Matlab.
Abstract: Fluid filled pipe system was widely used in the city water supply and drainage, water power, chemical machinery, aerospace, marine engineering and the nuclear industry and other fields, it was play an important role for improving the living standards of the nation and the national economic strength. Pipe conveying fluid was easy to design and manufacture, according to the characteristics of fluid conveying pipe, transformed the axial vibration mathematical model of the fluid conveying pipe, which considerate the fluid solid coupling to the beam element model for two nodes. Using Lagrangian interpolation function, the first order Hermit interpolation function and the Ritz method to obtain the element standard equation, and then integrated a global matrix equation, obtained the response of conveying fluid pipe with the Newmark method and Matlab. With the Matlab to simulate the axial motion equation of the conveying fluid pipe, study the response of the system in two aspect of fluid pressure disturbance and the fluid velocity disturbance, and the simulation results are analysed, which provides theoretical support for the work of fluid conveying pipes.
1 Jan 2014
TL;DR: It is confirmed that the water needs of this region have changed in recent years from being primarily for agricultural purposes to domestic and industrial uses currently.
Abstract: رف يهللادبع يلع ) 1 ( يمان ميحر دمحم ) 2 ( ماجنارس رداهب ) 3 ( هديكچ شور زا هدافتـسا اب يعبات جردم قرو يبيكرت دوم كرت ليلحت هلاقم نيا رد MLPG هدـش ماـجنا تـسا و ريثأـت تارـييغت و رادـقم هيواز ي رض رب صاوخ نايدارگ ا شنت تدش بي يكيمانيد لوا دوم ، و مود رثؤم يسررب يكيمانيد هدش تسا . تلاداعم لح يارب نامز هب هتسباو طسوت هك MLPG هدش هتسكش دنا شور ياه كراموين و يزكرم لضافت هدافتسا .تسا هدش رگا شور هچ لارگتنا J شور زا يكي موسرم ياه هبساحم رد ي اما تسا شنت تدش بيرض هب روط شور نيا يلك يعبات جردم داوم يارب هدافتـسا لـباق .تـسين نيارباـنب هـلاقم نـيا رد يارـب هبساحم ي ريسم زا لقتسم لارگتنا زا شنت تدش بيرض J* لومرف نگمهان داوم يارب هك ،هدش يدنب هدافتسا تسا هديدرگ . يم ناشن جياتن دهد لح رياس و قيقد لح اب يبوخ قباطت رضاح شور هك .دراد دوجوم ياه مه يم ناشن جياتن نينچ هك ،دهد رثكادح رادقم لقادح و تدش بيرض شنت رثؤم يارب E2/E1>1 هب بيترت هيواز رد ي نايدارگ صاوخ 0 و 90 يم خر هجرد يارب و دهد E2/E1<1 سكعلاب .