Space Flight Dynamic Simulations using Finite Element Results in Multibody System Codes

2009 ◽  
Author(s):  
O. Wallrapp ◽  
D. Sachau
Keyword(s):  
Finite Element ◽  
Space Flight ◽  
Multibody System ◽  
Dynamic Simulations

Kinematic sensitivity analysis of a novel micro-mechanism for displacement amplification

2018 ◽  
Vol 42 (4) ◽  
pp. 436-443 ◽  
Author(s):  
Sohail Iqbal ◽  
Afzaal Malik ◽  
Rana I Shakoor
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Geometric Parameters ◽  
Small Displacement ◽  
Extended Finite Element ◽  
Dynamic Simulations ◽  
Element Analysis ◽  
Amplification Mechanism ◽  
Kinematic Sensitivity

This research article presents the design and analysis of a displacement amplification mechanism based on a microelectromechanical system (MEMS). The mechanism, compared to generic displacement mechanisms, is smaller and capable of amplifying input displacement by a factor of 6.8. Finite element analysis (FEA) is performed with commercial software Intellisuite using the extended finite element method (XFEM) technique to verify the analytical results from mathematical models. Kinematic response and kinematic sensitivity analysis of the amplification mechanism are computationally carried out to predict the effect of different geometric parameters on the performance of the proposed mechanism. The analysis predicts that length and angle of flexure are the two key geometric parameters significantly affecting the amplification factor (AF), with length having a direct relationship and angle of flexure having an inverse relationship. A significant increase in the AF is seen for a flexure length up to 550 μm and angle below 5°. Based on the sensitivity analysis, the design is optimized, and geometric parameters are finalized. Modal analysis and dynamic simulations, including direct-integration transient and steady-state modal analysis, are performed on the mechanism under the application of 25 g. The mechanism can be integrated with any conventional actuating mechanism in a microsystem where the amplification of a small displacement at the output is desired.

Kinematics and Dynamics of a Multibody System of an Oilfield Pumping Unit by Means of Finite Element Method

1997 ◽  
Author(s):  
Si-zhu Zhou ◽  
Jacob Jen-Gwo Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Multibody System ◽  
Elastic System ◽  
Global Analysis ◽  
Oil Field ◽  
Kinematics And Dynamics ◽  
The Matrix ◽  
Pumping Unit ◽  
Element Method

Taking a multibody system of the oil field pumping unit into a multibody elastic system, this paper analyzes its kinematics and dynamics by means of finite element method, deduces the kinematics and dynamics function after doing the element’s and global analysis, and puts forward the procedures of this method, i.e., (1) dividing the system into elements; (2) calculating for the elements; (3) calculating the matrix of external force; (4) piling the element stiffness and mass matrixes up; and (5) solving the function. As an example, this paper illustrates the process of analyzing the multibody system of a PUMPING UNIT used in an oil field.

Study on the Mixed Method of Transfer Matrix Method and Finite Element Method for Vibration of Multibody System

2019 ◽  
Author(s):  
Hanjing Lu ◽  
Xiaoting Rui ◽  
Jianshu Zhang ◽  
Yuanyuan Ding
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Transfer Matrix ◽  
Mixed Method ◽  
Transfer Matrix Method ◽  
Transfer Equation ◽  
Matrix Method ◽  
Multibody System ◽  
Mass Matrix ◽  
Element Method

Abstract The mixed method of Transfer Matrix Method for Multibody System (MSTMM) and Finite Element Method (FEM) is introduced in this paper. The transfer matrix and transfer equation of multi-rigid-body subsystem are deduced by MSTMM. The mass matrix and stiffness matrix of flexible subsystem are calculated by FEM and then its dynamics equation is established. The connection point relations among subsystems are deduced and the overall transfer matrix and transfer equation of multi-rigid-flexible system are established. The vibration characteristics of the system are obtained by solving the system frequency equation. The computational results of two numerical examples show that the proposed method have good agreements with MSTMM and FEM. Multi-rigid-flexible-body system with multi-end beam can be solved by proposed method, which extends the application field of MSTMM and provides a theoretical basis for calculating complex systems with multi input end flexible bodies of arbitrary shape.

Dynamic Burst Pressure Simulation of Cylinder-Cylinder Intersections

2008 ◽  
Author(s):  
Cunjiang Cheng ◽  
G. E. Otto Widera
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Time History ◽  
Correlation Equation ◽  
Burst Pressure ◽  
Dynamic Simulations ◽  
Static Test ◽  
Shell Elements ◽  
Dynamic Correlation ◽  
Parameter Ranges

In this study, the determination of the burst pressure of a series of cylinder-cylinder intersections representing vessels of diameter D and wall thickness T, and nozzles of diameter d and wall thickness t subjected to short-term dynamic loading is investigated. Dynamic simulations via the use of the finite element method are carried out to determine the effects of dimensionless parameters d/D, D/T and t/T as well as pressure vs. time history. The LS-DYNA software is employed to model and analyze various intersections for the geometric parameter ranges 0.1 ≤ d/D < 1.0, 0.1 ≤ t/T ≤ 3 and 50 ≤ D/T ≤ 250. The use of both solid and shell elements is investigated and applied in this study. A correlation equation to predict the dynamic burst pressure of cylinder-cylinder intersections is proposed based on the parametric finite element analyses. Static test data is used to verify the dynamic correlation equation by applying a relatively long pressure pulse duration.

Identification of Free-Free Modes From Constrained Vibration Data for Flexible Multibody Models

1999 ◽  
Author(s):  
Tong Y. Yi ◽  
Parviz E. Nikravesh
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Degrees Of Freedom ◽  
Multibody System ◽  
Element Model ◽  
Flexible Body ◽  
Fe Model ◽  
Modal Data ◽  
Vibration Data

Abstract This paper presents a method for identifying the free-free modes of a structure by utilizing the vibration data of the same structure with boundary conditions. In modal formulations for flexible body dynamics, modal data are primary known quantities that are obtained either experimentally or analytically. The vibration measurements may be obtained for a flexible body that is constrained differently than its boundary conditions in a multibody system. For a flexible body model in a multibody system, depending upon the formulation used, we may need a set of free-free modal data or a set of constrained modal data. If a finite element model of the flexible body is available, its vibration data can be obtained analytically under any desired boundary conditions. However, if a finite element model is not available, the vibration data may be determined experimentally. Since experimentally measured vibration data are obtained for a flexible body supported by some form of boundary conditions, we may need to determine its free-free vibration data. The aim of this study is to extract, based on experimentally obtained vibration data, the necessary free-free frequencies and the associated modes for flexible bodies to be used in multibody formulations. The available vibration data may be obtained for a structure supported either by springs or by fixed boundary conditions. Furthermore, the available modes may be either a complete set; i.e., as many modes as the number of degrees of freedom of the associated FE model is available, or it can be an incomplete set.

Integration of Large Deformation Finite Element and Multibody System Algorithms

2007 ◽  
Vol 2 (4) ◽  
pp. 351-359 ◽  
Author(s):  
Ahmed A. Shabana ◽  
Olivier A. Bauchau ◽  
Gregory M. Hulbert
Keyword(s):  
Finite Element ◽  
Large Deformation ◽  
Multibody System ◽  
General Purpose ◽  
Element Formulation ◽  
Computer Algorithms ◽  
Flexible Multibody System ◽  
Nonlinear Constraint ◽  
Flexible Multibody ◽  
Computer Codes

This paper presents an overview of research and development efforts that are currently being devoted to integrate large deformation finite element formulations with flexible multibody system algorithms. The goal is to develop computer simulation capabilities for the analysis of physics and engineering models with significant details. The successful development of such new and integrated algorithms will also allow modeling and simulation of systems that cannot be solved using existing computer algorithms and codes. One of the main difficulties encountered in this integration process is attributed to the fact that the solution procedures used in finite element codes differ significantly from those used in general-purpose flexible multibody system codes. Finite element methods employ the corotational formulations that are often used with incremental solution procedures. Flexible multibody computer codes, on the other hand, do not, in general, use incremental solution procedures. Three approaches are currently being explored by academic institutions and the software industry. In the first approach, gluing algorithms that aim at performing successful simulations by establishing an interface between existing codes are used. Using different coordinates and synchronizing the time stepping are among several challenging problems that are encountered when gluing algorithms are used. In the second approach, multibody system capabilities are implemented in existing finite element algorithms that are based on large rotation vector formulations. For the most part, corotational formulations and incremental solution procedures are used in this case. In the third approach, a new large deformation finite element formulation that can be successfully implemented in flexible multibody system computer algorithms that employ nonincremental solution procedures is introduced. The approach that is now being developed in several institutions is based on the finite element absolute nodal coordinate formulation. Such a formulation can be systematically implemented in general-purpose flexible multibody system computer algorithms. Nonlinear constraint equations that describe mechanical joints between different bodies can be formulated in terms of the absolute coordinates in a straightforward manner. The coupling between the motion of rigid, flexible, and very flexible bodies can also be accurately described. The successful integration of large deformation finite element and multibody system algorithms will lead to a new generation of computer codes that can be systematical and efficiently used in the analysis of many engineering applications.

The Cosserat Point Element as an Accurate and Robust Finite Element Formulation for Implicit Dynamic Simulations

2019 ◽  
Vol 17 (01) ◽  
pp. 1844006
Author(s):  
Mahmood Jabareen ◽  
Yehonatan Pestes
Keyword(s):  
Finite Element ◽  
Energy Function ◽  
Strain Energy ◽  
Three Dimensional ◽  
Nonlinear Dynamic Analysis ◽  
Strain Energy Function ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Dynamic Simulations ◽  
Cosserat Point

The reliability of numerical simulations manifested the need for an accurate and robust finite element formulation. Therefore, in the present study, an eight node brick Cosserat point element ( CPE ) for the nonlinear dynamic analysis of three-dimensional (3D) solids including both thick and thin structures is developed. Within the present finite element formulation, a strain energy function is proposed and additively decoupled into two parts. One part is characterized by any 3D strain energy function, while the other part controls the response to inhomogeneous deformations. Several example problems are presented, which demonstrate the accuracy and the robustness of the developed CPE in modeling the dynamic response of elastic structures.

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