Simulation of Pipeline Dynamics Using an Optimized Finite Element Model

1999 ◽  
Vol 11 (4) ◽  
pp. 283-288
Author(s):  
Kazushi Sanada ◽  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
State Space ◽  
Fuel Injection ◽  
Block Diagram ◽  
Finite Element Approximation ◽  
Element Model ◽  
Simulation Software ◽  
Element Approximation ◽  
Space Equation

Applying finite element approximation to basic equations of pipeline dynamics, we propose an optimized finite element model written as a state space equation having a state variable vector of flows and pressures at intersecting grid points. The model accepts various forms of friction. We propose an augmented model including unsteady laminar friction rewritten as a state space equation. A model generator program is developed to calculate coefficient matrices of the state space equation of the model. Using the program, the model is compatible with block-diagram-based simulation software. Use of the model is shown by experiment and simulation examples. Transient pressures of a closed-end pipe were measured experimentally and used to validate simulated results of the optimized finite element model. Fuel injection was simulated using commercial simulation software to demonstrate model use.

scholarly journals Piezoelectric Beam Finite Element Model and Its Reduction and Control

2021 ◽  
Vol 71 (1) ◽  
pp. 87-106
Author(s):  
Kutiš Vladimír ◽  
Paulech Juraj ◽  
Gálik Gálik ◽  
Murín Justín
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
State Space ◽  
State Space Model ◽  
Element Model ◽  
Functionally Graded ◽  
Fem Model ◽  
Space Model ◽  
Piezoelectric Beam ◽  
Reduced State

Abstract The paper deals with the development of the finite element method (FEM) model of piezoelectric beam elements, where the piezoelectric layers are located on the outer surfaces of the beam core, which is made of functionally graded material. The created FEM model of piezoelectric beam structure is reduced using the modal truncation method, which is one of model order reduction (MOR) method. The results obtain from reduced state-space model are compared with results obtain from finite element model. MOR state-space model is also used in the design of the linear quadratic regulator (LQR). Created reduced state-space model with feedback with the LQR controller is analysed and compared with the results from FEM model.

Design of Robust Vibration Controller for a Smart Panel Using Finite Element Model

2002 ◽  
Vol 124 (2) ◽  
pp. 265-276 ◽  
Author(s):  
W. Chang ◽  
Senthil V. Gopinathan ◽  
V. V. Varadan ◽  
V. K. Varadan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Reduction ◽  
State Space ◽  
State Space Model ◽  
Element Model ◽  
Robust Controller ◽  
Space Model ◽  
Smart Panel ◽  
Low Order

This paper presents a model reduction method and uncertainty modeling for the design of a low-order H∞ robust controller for suppression of smart panel vibration. A smart panel with collocated piezoceramic actuators and sensors is modeled using solid, transition, and shell finite elements, and then the size of the model is reduced in the state space domain. A robust controller is designed not only to minimize the panel vibration excited by applied uniform acoustic pressure, but also to be reliable in real world applications. This paper introduces the idea of Modal Hankel Singular values (MHSV) to reduce the finite element model to a low-order state space model with minimum model reduction error. MHSV measures balanced controllability and observability of each resonance mode to deselect insignificant resonance modes. State space modeling of realistic control conditions are formulated in terms of uncertainty variables. These uncertainty variables include uncertainty in actuators and sensors performances, uncertainty in the knowledge of resonance frequencies of the structure, damping ratio, static stiffness, unmodeled high resonance vibration modes, etc. The simplified model and the uncertainty model are combined as an integrated state space model, and then implemented in the H∞ control theory for controller parameterization. The low-order robust controller is easy to implement in an analog circuit to provide a low cost solution in a variety of applications where cost may be a limiting factor.

scholarly journals Monte Carlo particle-in-cell methods for the simulation of the Vlasov–Maxwell gyrokinetic equations

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
A. Bottino ◽  
E. Sonnendrücker
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Equations Of Motion ◽  
Continuous Distribution ◽  
Finite Element Approximation ◽  
Element Model ◽  
Element Approximation ◽  
Field Equations ◽  
Particle In Cell ◽  
Pic Method

The particle-in-cell (PIC) algorithm is the most popular method for the discretisation of the general 6D Vlasov–Maxwell problem and it is widely used also for the simulation of the 5D gyrokinetic equations. The method consists of coupling a particle-based algorithm for the Vlasov equation with a grid-based method for the computation of the self-consistent electromagnetic fields. In this review we derive a Monte Carlo PIC finite-element model starting from a gyrokinetic discrete Lagrangian. The variations of the Lagrangian are used to obtain the time-continuous equations of motion for the particles and the finite-element approximation of the field equations. The Noether theorem for the semi-discretised system implies a certain number of conservation properties for the final set of equations. Moreover, the PIC method can be interpreted as a probabilistic Monte Carlo like method, consisting of calculating integrals of the continuous distribution function using a finite set of discrete markers. The nonlinear interactions along with numerical errors introduce random effects after some time. Therefore, the same tools for error analysis and error reduction used in Monte Carlo numerical methods can be applied to PIC simulations.

scholarly journals Vibration control of a lead zirconate titanate structure considering controller–structure interactions

2018 ◽  
Vol 37 (4) ◽  
pp. 1201-1218 ◽  
Author(s):  
Xingjian Dong ◽  
Zhike Peng ◽  
Guang Meng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
State Space ◽  
State Space Model ◽  
Element Model ◽  
The State ◽  
Laminated Plate ◽  
Space Model ◽  
Model Based ◽  
The Finite Element Model

This study focuses on integrating an active vibration controller into the finite element model of a piezoelectric laminated plate with the controller–structure interactions considered. A finite element model of a piezoelectric laminated plate is formulated using the third-order shear deformation theory. A state-space model is set up by performing a system identification technique. The state-space model is then used to design an optimal vibration controller. Considering that the finite element model is more appropriate than state-space model for dynamic simulation, the state-space model-based controller is integrated into the finite element model to capture the controller–structure interactions. The results obtained by applying vibration controller in state-space model are also presented to make a comparison. It is numerically demonstrated that the controller–structure interactions occur and cause performance degradation in case that the state-space model-based controller works with the finite element model. There is no prior guarantee that a state-space model-based controller satisfying the control requirements still works well in closed loop with the finite element model. The results of this study can be used to evaluate the controller performance for the piezoelectric smart structures during the preliminary design stage.

scholarly journals Concept Calculation Tool for Dynamics of Generator Set Common Baseframe

2017 ◽  
Vol 50 (3) ◽  
pp. 353-356 ◽  
Author(s):  
Johannes Heilala ◽  
Teemu Kuivaniemi ◽  
Juho Könnö ◽  
Tero Frondelius
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequency ◽  
Element Model ◽  
Simulation Software ◽  
Design Tool ◽  
Vibration Response ◽  
Model Generation ◽  
Concept Design ◽  
Common Base

The Natural frequency and vibration response calculation process of a generator set was automatized so that it can be used in a generator set common base frame concept design. The implementation of automatization was to be done so that no profound knowledge about the finite element method is needed to execute calculations and that computation times are short. Substructuring is used for certain parts of the generator set model to reduce the computation times for more a efficient concept design process. The common base frame concept design is implemented to the process by using a design tool in which the finite element model generation from parametric geometry is automatized. Generator set finite element model generation, natural frequency and vibration response calculations and post-processing of analysis results were implemented by developing a calculation tool for this purpose. The calculation tool is an independent application that uses Abaqus simulation software to execute analyses.

scholarly journals ABOUT SOLUTION OF MULTIPOINT BOUNDARY PROBLEMS OF TWO-DIMENSIONAL STRUCTURAL ANALYSIS WITH THE USE OF COMBINED APPLICATION OF FINITE ELEMENT METHOD AND DISCRETE-CONTINUAL FINITE ELEMENT METHOD PART 2: SPECIAL ASPECTS OF FINITE ELEMENT APPROXIMATION

2017 ◽  
Vol 13 (4) ◽  
pp. 14-36
Author(s):  
Pavel A. Akimov ◽  
Alexander M. Belostotsky ◽  
Taymuraz B. Kaytukov ◽  
Oleg A. Negrozov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Problem ◽  
Finite Element Approximation ◽  
Element Model ◽  
Discrete Models ◽  
Element Approximation ◽  
Multipoint Boundary ◽  
Joint Application ◽  
Element Method

As is well known, the formulation of a multipoint boundary problem involves three main components: a description of the domain occupied by the structure and the corresponding subdomains; description of the conditions inside the domain and inside the corresponding subdomains, the description of the conditions on the boundary of the domain, conditions on the boundaries between subdomains. This paper is a continuation of another work published earlier, in which the formulation and general principles of the approximation of the multipoint boundary problem of a static analysis of deep beam on the basis of the joint application of the finite element method and the discrete-continual finite element method were considered. It should be noted that the approximation within the fragments of a domain that have regular physical-geometric parameters along one of the directions is expedient to be carried out on the basis of the discrete-continual finite element method (DCFEM), and for the approximation of all other fragments it is necessary to use the standard finite element method (FEM). In the present publication, the formulas for the computing of displacements partial derivatives of displacements, strains and stresses within the finite element model (both within the finite element and the corresponding nodal values (with the use of averaging)) are presented. Boundary conditions between subdomains (respectively, discrete models and discrete-continual models and typical conditions such as “hinged support”, “free edge”, “perfect contact” (twelve basic (basic) variants are available)) are under consideration as well. Governing formulas for computing of elements of the corresponding matrices of coefficients and vectors of the right-hand sides are given for each variant. All formulas are fully adapted for algorithmic implementation.

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