Simulations of a Truck Driving on a Flexible Bridge

1997 ◽  
Author(s):  
Olof Friberg ◽  
Peter Möller ◽  
Boris Thorvald
Keyword(s):  
Computer Program ◽  
Multibody Dynamics ◽  
Time Integration ◽  
Realistic Model ◽  
Bridge Structure ◽  
Control Logic ◽  
Structure Interaction ◽  
Time Stepping ◽  
Common Time ◽  
Vehicle Structure

Abstract In this work, the main object was to perform simulations using a realistic model of a truck and trailer passing over a flexible bridge structure. Two driving cases were considered: straight forward driving with and without braking. In the latter case control logic was used to distribute the braking torques to the wheel axles. A general multibody dynamics computer program, DADS, and its tire subroutines were interfaced with our FEM routines in order to create a vehicle/structure interaction computer program. A part of this process was to integrate different time stepping algorithms from the multibody dynamics and FEM disciplines into a “common” time integration procedure. Another part was to write code to search for finite elements where tire/structure interaction takes place.

The Analysis and Design of a Fire Engine Safety Cab Using Finite Element Methods

1977 ◽  
Vol 191 (1) ◽  
pp. 187-193 ◽  
Author(s):  
J. C. Miles ◽  
G. A. Wardill
Keyword(s):  
Finite Element ◽  
Computer Program ◽  
Three Dimensional ◽  
Analysis And Design ◽  
Vehicle Structure ◽  
Collapse Analysis ◽  
Incremental Formulation ◽  
Analysis Computer ◽  
Fire Engine ◽  
Analysis Computer Program

A three dimensional structural collapse analysis computer program is described, and illustrated by reference to a safety vehicle structure analysed and designed using the program. The particular problems of large displacements and material non-linearity are accounted for, and a method of estimating the permanent set which results after impact is described. Based on an incremental formulation of the conventional finite-element method, the computer program is capable of tracing the complete load deflection characteristics of a structure up to and beyond the point of collapse.

Time Integration Incorporated Sensitivity Analysis With Generalized-α Method for Multibody Dynamics Systems

2011 ◽  
Author(s):  
Guang Dong ◽  
Zheng-Dong Ma ◽  
Gregory Hulbert ◽  
Noboru Kikuchi
Keyword(s):  
Sensitivity Analysis ◽  
Topology Optimization ◽  
Dynamic Loading ◽  
Multibody Dynamics ◽  
Equations Of Motion ◽  
Time Integration ◽  
Optimization Method ◽  
Sensitivity Analysis Method ◽  
System Equations ◽  
Consecutive Time

The topology optimization method is extended for the optimization of geometrically nonlinear, time-dependent multibody dynamics systems undergoing nonlinear responses. In particular, this paper focuses on sensitivity analysis methods for topology optimization of general multibody dynamics systems, which include large displacements and rotations and dynamic loading. The generalized-α method is employed to solve the multibody dynamics system equations of motion. The developed time integration incorporated sensitivity analysis method is based on a linear approximation of two consecutive time steps, such that the generalized-α method is only applied once in the time integration of the equations of motion. This approach significantly reduces the computational costs associated with sensitivity analysis. To show the effectiveness of the developed procedures, topology optimization of a ground structure embedded in a planar multibody dynamics system under dynamic loading is presented.

scholarly journals THE PARAMETRIC OSCILLATIONS OF ROTATING ELASTIC RODS UNDER THE ACTION OF THE PERIODIC AXIAL FORCES

2020 ◽  
pp. 56-64
Author(s):  
Petro Lizunov ◽  
Valentyn Nedin
Keyword(s):  
Differential Equations ◽  
Computer Program ◽  
Block Diagram ◽  
Time Integration ◽  
Numerical Differentiation ◽  
Oscillatory Motion ◽  
Elastic Rods ◽  
Axial Forces ◽  
General Block Diagram ◽  
Rotating Rods

The paper presents the results of numerical investigation of the periodic axial forces’ influence on the transverse oscillations of long rotating rods. The gyroscopic inertia forces are taken to account and space oscillating process of rotating rods is considered with account of geometric nonlinearity. The study has been done with computer program with a graphical interface that is developed by authors. The process of numerical solution of the differential equations of oscillations of rotating rods using the method of numerical differentiation of rod’s bend forms by polynomial spline-functions and the Houbolt time integration method is described. A general block diagram of the algorithm is shown. This algorithm describes the process of repeated (cyclical) solving of the system of differential equations of oscillations for every point of mechanical system in order to find the new coordinates of the positions of these points in each next point of time t+∆t. The computer program in which the shown algorithm is realized allows to monitor for the behavior of moving computer model, which demonstrates the process of oscillatory motion in rotation. Moreover, the program draws the graphics of oscillations and changes of angular speeds and accelerations in different coordinate systems. Using this program, the dynamics of a range of objects which are modeled by long elastic rods have been studied. For investigated objects is shown that on various rotational speeds and beat frequencies the oscillatory motion of the rods occurs with different character of behavior. On certain speeds with different frequencies of axial load the oscillations have definite periodicity and occur with beats of amplitude which are the result of the periodic axial force action.

Combined Viscous and Plastic Deformations in Two-Dimensional Large Strain Finite Element Analysis

1985 ◽  
Vol 107 (1) ◽  
pp. 13-18 ◽  
Author(s):  
B. V. Kiefer ◽  
P. D. Hilton
Keyword(s):  
Finite Element ◽  
Input Parameter ◽  
Time Integration ◽  
Strain Increment ◽  
Total Strain ◽  
Two Dimensional ◽  
Elastic Plastic ◽  
Time Stepping ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

Capabilities for the analysis of combined viscous and plastic behavior have been added to an existing finite element computer program for two-dimensional elastic-plastic calculations. This program (PAPSTB) has been formulated for elastic-plastic stress and deformation analyses of two-dimensional and axisymmetric structures. It has the ability to model large strains and large deformations of elastic-perfectly plastic, multi-linear hardening, or power-hardening materials. The program is based on incremental plasticity theory with a von Mises yield criterion. Time dependent behavior has been introduced into the PAPSTB program by adding a viscous strain increment to the elastic and plastic strain increment to form the total strain increment. The viscous calculations presently employ a power-law relationship between the viscous strain rate and the effective stress. The finite element code can be easily modified to handle more complex viscous models. The Newmark method for time integration is used, i.e., an input parameter is included which enables the user to vary the time domain approximation between forward (explicit) and backward (implicit) difference. Automatic time stepping is used to provide for stability in the viscous calculations. It is controlled by an input parameter related to the ratio of the current viscous strain increment to the total strain. The viscoplastic capabilities of the PAPSTB program are verified using the axisymmetric problem of an internally pressurized, thick-walled cylinder. The transient viscoplastic case is analyzed to demonstrate that the elastic-perfectly plastic solution is obtained as a steady-state condition is approached. The influence of varying the time integration parameter for transient viscoplastic calculations is demonstrated. In addition, the effects of time step on solution accuracy are investigated by means of the automatic time stepping algorithm in the program. The approach is then applied to a simple forging problem of cylinder upsetting.

Explicit and Implicit Code Coupling Schemes in Fluid Structure Interaction

2005 ◽  
Author(s):  
E. Longatte ◽  
Z. Bendjeddou ◽  
V. Verreman ◽  
M. Souli
Keyword(s):  
Fluid Structure Interaction ◽  
Time Integration ◽  
Good Choice ◽  
Integration Scheme ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Field ◽  
Analytical Test ◽  
Time Integration Scheme ◽  
Implicit Code

In multi-physics numerical computations a good choice of code coupling schemes is required. Several methods are possible like: an explicit synchronous scheme an Euler implicit method and no interpolation on velocity pressure; an explicit asynchonous scheme using a Crank-Nicholson time integration scheme and interpolation on velocity and pressure; an implicit scheme using a fixed iterative method. In the present paper these different schemes are compared for application in fluid structure interaction field. In the first part numerical coupling schemes are presented. Then their capability to ensure energy conservation is discussed according to numerical results obtained in analytical test cases. Finally application of coupling process to fluid structure interaction problems is investigated and results are discussed in terms of added mass and damping induced by a fluid for a structure vibrating in fluid at rest.

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