Geometric Non-Linear Influence of a Payload Fairing on Dynamic Displacement Response

2000 ◽  
Author(s):  
V. Ramamurti ◽  
S. Rajarajan ◽  
G. V. Rao
Keyword(s):  
Shell Element ◽  
Superposition Method ◽  
Time Step ◽  
Dynamic Displacement ◽  
Displacement Response ◽  
Mode Superposition Method ◽  
Plate And Shell ◽  
Non Linear ◽  
Deformed State ◽  
Payload Fairing

Abstract Finite element method using three noded plate and shell element and 3D beam element in conjunction with mode superposition method is used for studying the large dynamic displacement response of a typical payload fairing due to separation impulse. Incremental technique is used for solving the geometric non-linear problem. Linear formulations are assumed and a step-by-step analysis is performed on the deformed state of each previous time step. The geometry is updated and the stiffness matrix recomputed after every finite time step and the eigenvalue analysis repeated.

Uncertain Response Analysis of Fractionally-Damped Beams Based on Interval Process Model

2021 ◽  
Author(s):  
C. K. Shen ◽  
D. Mi ◽  
J. W. Li
Keyword(s):  
Stochastic Process ◽  
Vibration Analysis ◽  
Process Model ◽  
Response Analysis ◽  
Time Interval ◽  
Superposition Method ◽  
Middle Point ◽  
Dynamic Displacement ◽  
Displacement Response ◽  
The Laplace Transform

In the uncertain vibration analysis of fractionally-damped beams whose damping characteristic is described using fractional derivative model, the uncertain excitation is usually modeled as a stochastic process. However, it is often difficult to obtain sufficient samples of the excitation to establish a precise probability distribution function for the stochastic process model in practical engineering problems. Hence, in this paper, a nonrandom vibration analysis method for fractionally-damped beams is proposed to obtain the dynamic displacement response bounds of the beams under the uncertain excitation. Specifically, the uncertain excitation applied to the fractionally-damped beam is treated as a spatial-time interval field, so that the dynamic displacement response of the beam is also a space-time interval field. The middle point function and the radius function of the displacement response of the fractionally-damped beam can be derived based on the modal superposition method and the Laplace transform, through which the bound functions of the dynamic displacement response can be obtained. In addition, several numerical examples are given to demonstrate the effectiveness of the proposed method.

Dynamic Buckling Analysis of Axi-Symmetric Shells

Volume 2 ◽  
2004 ◽  
Author(s):  
Yaghob Gholipour
Keyword(s):  
Natural Frequency ◽  
Stiffness Matrix ◽  
Memory Management ◽  
Shell Element ◽  
Buckling Analysis ◽  
Dynamic Buckling ◽  
Mode Shapes ◽  
Response Analysis ◽  
Superposition Method ◽  
Mode Superposition Method

In the field of dynamic buckling analysis of shell structures, the effect of vibration on buckling load and the effect of axial loads on vibration are very interesting phenomena. In this work the finite element method has been applied for dynamic buckling analysis of axi-symmetric shell. The degenerated axi-symmetric shell element and subspace iteration technique has been used to carry out the analysis. The stiffness matrix is stored in band form to have efficient memory management and the 3 × 3 gauss quadrature has been used for calculation of element stiffness matrix and consistent load vector. An attempt is made to study the effect of static in-plane edge loads on the fundamental frequency of axi-symmetric shells. The effect of vibration at a prescribed frequency on the buckling behavior of shell is also investigated. From the limited analysis carried out, it is found that the presence of static in-plane edge loads considerably affects the natural frequency and hence necessitates the evaluation of appropriate natural frequency and mode shapes for use in realistically carrying out the dynamic response analysis of structures subjected to forced vibration by mode superposition method.

scholarly journals Collocation Methods for High-Order Well-Balanced Methods for Systems of Balance Laws

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1799
Author(s):  
Irene Gómez-Bueno ◽  
Manuel Jesús Castro Díaz ◽  
Carlos Parés ◽  
Giovanni Russo
Keyword(s):  
High Order ◽  
Collocation Methods ◽  
Quadrature Formulas ◽  
Balance Laws ◽  
Source Terms ◽  
Time Step ◽  
Systems Of Balance Laws ◽  
Reconstruction Operator ◽  
Non Linear ◽  
Linear Problems

In some previous works, two of the authors introduced a technique to design high-order numerical methods for one-dimensional balance laws that preserve all their stationary solutions. The basis of these methods is a well-balanced reconstruction operator. Moreover, they introduced a procedure to modify any standard reconstruction operator, like MUSCL, ENO, CWENO, etc., in order to be well-balanced. This strategy involves a non-linear problem at every cell at every time step that consists in finding the stationary solution whose average is the given cell value. In a recent paper, a fully well-balanced method is presented where the non-linear problems to be solved in the reconstruction procedure are interpreted as control problems. The goal of this paper is to introduce a new technique to solve these local non-linear problems based on the application of the collocation RK methods. Special care is put to analyze the effects of computing the averages and the source terms using quadrature formulas. A general technique which allows us to deal with resonant problems is also introduced. To check the efficiency of the methods and their well-balance property, they have been applied to a number of tests, ranging from easy academic systems of balance laws consisting of Burgers equation with some non-linear source terms to the shallow water equations—without and with Manning friction—or Euler equations of gas dynamics with gravity effects.

scholarly journals Transient Response of Bridge Piers to Structure Separation under Near-Fault Vertical Earthquake

2021 ◽  
Vol 11 (9) ◽  
pp. 4068
Author(s):  
Wenjun An ◽  
Guquan Song
Keyword(s):  
Large Scale ◽  
Bending Moment ◽  
Relative Displacement ◽  
Superposition Method ◽  
Longitudinal Displacement ◽  
Transient Wave ◽  
Vibration Period ◽  
Vertical Excitation ◽  
Mode Superposition Method ◽  
Main Girder

Given the possible separation problem caused by the double-span continuous beam bridge under the action of the vertical earthquake, considering the wave effect, the transient wave characteristic function method and the indirect mode superposition method are used to solve the response theory of the bridge structure during the earthquake. Through the example analysis, the pier bending moment changes under different vertical excitation periods and excitation amplitudes are calculated. Calculations prove that: (1) When the seismic excitation period is close to the vertical natural vibration period of the bridge, the main girder and the bridge pier may be separated; (2) When the pier has a high height, the separation has a more significant impact on the longitudinal displacement of the bridge, but the maximum relative displacement caused by the separation is random; (3) Large-scale vertical excitation will increase the number of partitions of the structure, and at the same time increase the vertical collision force between the main girder and the pier, but the effect on the longitudinal displacement of the form is uncertain; (4) When V/H exceeds a specific value, the pier will not only be damaged by bending, but will also be damaged by axial compression.

Time step selection for 6-noded non-linear joint element in elasto-viscoplasticity analyses

1990 ◽  
Vol 10 (1) ◽  
pp. 33-58 ◽  
Author(s):  
Koji Sekiguchi ◽  
R.Kerry Rowe ◽  
Kwan Yee Lo
Keyword(s):  
Time Step ◽  
Non Linear ◽  
Joint Element ◽  
Selection For ◽  
Step Selection

A refined non-linear non-conforming triangular plate/shell element

2003 ◽  
Vol 56 (15) ◽  
pp. 2387-2408 ◽  
Author(s):  
Y. X. Zhang ◽  
Y. K. Cheung
Keyword(s):  
Shell Element ◽  
Triangular Plate ◽  
Non Linear
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