Structural Physical Parameter Identification Based on Empirical Genetic-Simplex Algorithm and Structural Dynamic Response

2011 ◽  
Vol 94-96 ◽  
pp. 1998-2004
Author(s):  
Li Ping Jiang ◽  
Wei Liu ◽  
Lei Shi ◽  
Yan Liu
Keyword(s):  
Genetic Algorithm ◽  
Dynamic Response ◽  
Parameter Identification ◽  
Physical Parameter ◽  
Degrees Of Freedom ◽  
Simplex Algorithm ◽  
Physical Parameters ◽  
Running Speed ◽  
Structural Dynamic ◽  
Calculation Step

In the complex conversion analysis of multi-degrees of freedom，large calculation count needed in each calculation step of Genetic Algorithm limits the running speed of genetic algorithm. So the positive calculation count to be reduced is an effective method to enlarge the range of GA’s application. Empirical Genetic-Simplex Algorithm (EGSA) proposed in this paper is one of the effective methods to solve the problem. This method is applied to structural physical parameters identification based on the structural dynamic response. The result shows that EGSA has many advantages on precision, efficiency in searching, strong to resist the noise, and good adaptation to the incomplete information.

scholarly journals Dynamic response of a wedge through asymmetric free fall in 2 degrees of freedom

2017 ◽  
Vol 233 (1) ◽  
pp. 229-250 ◽  
Author(s):  
Parviz Ghadimi ◽  
Sasan Tavakoli ◽  
Abbas Dashtimanesh ◽  
Pouria Taghikhani
Keyword(s):  
Experimental Data ◽  
Dynamic Response ◽  
Degrees Of Freedom ◽  
Time Derivative ◽  
Free Fall ◽  
Added Mass ◽  
Roll Motion ◽  
Physical Parameters ◽  
Two Dimensional ◽  
Roll Speed

In this article, a mathematical model is presented for simulation of the coupled roll and heave motions of the asymmetric impact of a two-dimensional wedge body. This model is developed based on the added mass theory and momentum variation. To this end, new formulations are introduced which are related to the added mass caused by heave and roll motions of the wedge. These relations are developed by including the asymmetrical effects and roll speed. In addition, by considering the roll speed, a particular method is presented for the time derivative of half-wetted beam of an asymmetric wedge. Furthermore, two equations are derived for the roll and heave motions in which damping terms appear. Validity of the proposed method is verified by comparing the predicted results against available experimental data in two conditions of roll motion and no roll motion. Favorable agreement is observed between the predicted results and experimental data. The pressure and hydrodynamic load are computed, and the differences between the results associated with the considered conditions are explored. Subsequently, the effects of different physical parameters including deadrise angle, initial roll angle, and initial velocity on the dynamic response of a two-dimensional wedge section are investigated. Ultimately, time histories of hydrodynamic coefficients are determined in order to provide a better understanding of the derived equations.

Development of Physical-Parameter Identification Procedure for Energy-Dissipated Buildings with Symmetric Ductile Braces

2013 ◽  
Vol 479-480 ◽  
pp. 1149-1154
Author(s):  
Ming Chih Huang ◽  
Yen Po Wang ◽  
Tzu Kang Lin ◽  
Jer Fu Wang
Keyword(s):  
System Identification ◽  
Parameter Identification ◽  
Physical Parameter ◽  
Primary Structure ◽  
Substantial Reduction ◽  
Physical Parameters ◽  
Hysteretic Model ◽  
Identification Procedure ◽  
Restoring Force ◽  
Energy Dissipated

In this paper, a pseudo-single-degree-of-freedom system identification procedure is developed to investigate the dynamic characteristics of energy-dissipated buildings equipped with symmetric ductile braces (SDBs). The primary structure is assumed to be linear on account of substantial reduction of seismic forces due to the installation of SDBs for which a bilinear hysteretic model is considered. The hysteretic model is in turn characterized by a backbone curve by which the multi-valued restoring force is transformed into a single-valued function. With the introduction of backbone curves, the system identification analysis of inelastic structures is significantly simplified. The proposed algorithm extracts individually the physical parameters of each primary structure and each energy-dissipation device that are considered useful information in the structural health monitoring. A numerical example is conducted to demonstrate the feasibility of using the proposed technique for physical parameter identification of partially inelastic energy-dissipated buildings.

Physical Parameter Identification of Laminates Based on Thermal Deformation Measurements

1995 ◽  
Author(s):  
Werner Konrad ◽  
Bernd Caesar
Keyword(s):  
Parameter Identification ◽  
Physical Parameter ◽  
High Precision ◽  
Model Updating ◽  
Nodal Point ◽  
Design Parameters ◽  
Physical Parameters ◽  
Spherical Mirror ◽  
Load Case ◽  
Space Applications

Abstract High precision structures, as telescope mirrors for space applications, require high thermal stability and structural stiffness combined with low weight. Laminate structures with their special properties can satisfy these stringent requirements. Model updating and physical parameter identification on the basis of measurements can be applied to optimize such structures or define correction measures w.r.t. manufacturing inaccuracies. In classic update procedures correction factors are used to improve physical parameters. The definition of correction differences which are suitable for parameters with zero starting values or values changing from positive to negative as it may be the case for the layer orientations of a laminate is presented. High precision structures require high accurate measuring methods for the test. Thermal deformations can be measured by holographic, interferometric methods with high precision in the μm range. An interferometric contour map can be compared with the nodal point displacements of a Finite Element model by special spline functions called Zernike’s polynomials. The equations to determine the various design parameters or material properties may not be linear independent, depending on the applied thermal load case. The degree of correlation between the various parameters is investigated. The results are used to optimize the load case selection and to improve error localization methods. The proposed method is applied to a segment of a high stability spherical mirror plate with real measuring data.

Dynamic Response Analysis for Structures with Interval Parameters Based on Affine Arithmetic

2008 ◽  
Vol 44-46 ◽  
pp. 157-164
Author(s):  
Zeng Qing Zhu ◽  
J.J. Chen
Keyword(s):  
Dynamic Response ◽  
Engineering Application ◽  
Geometric Dimension ◽  
Response Analysis ◽  
Physical Parameters ◽  
Structural Dynamic ◽  
Affine Arithmetic ◽  
Interval Parameters ◽  
Uncertain Structure ◽  
General Affine

This paper aims to study the uncertainty of the MDOF structural dynamic response, taking not only the interval characteristics of structural physical parameters and geometric dimension, but also the interval characteristics of applied load simultaneously . By means of the description of the interval parameters of uncertain structure with affine forms, the interval structural dynamic equation is studied, and an improved affine arithmetic based on interval division is presented, where correlations between the interval elements in eigenvalue and responses equations are considered, independent uncertain parameters are transformed to affine forms, and the solution of eigenvalue and response equations are transformed into the corresponding certain ones. With general affine arithmetic, the eigenvalue of each order and response bounds are determined by searching for the maximum and minimum in the solutions. Finally, some mathematical examples and a further engineering application confirm the feasibility and validity of this approach.

Identification of Parameter Matrices Using Residual Force Vector

2013 ◽  
Vol 394 ◽  
pp. 157-162 ◽  
Author(s):  
Hee Chang Eun ◽  
Rae Jung Kim ◽  
Young Jun Ahn
Keyword(s):  
Dynamic Response ◽  
Physical Parameter ◽  
Measurement Errors ◽  
Dynamic Behaviour ◽  
Physical Parameters ◽  
Force Vector ◽  
Mass Matrices ◽  
Residual Force ◽  
The Difference ◽  
The Cost

The physical parameters obtained from modal tests do not satisfy the eigenvalue function due to modeling and measurement errors, and unexpected damage. The desired dynamic response can be obtained by identifying the most appropriate changes required to obtain the desired dynamic behaviour. The purpose of this study is to present the analytical equations on the updated stiffness and mass matrices in the satisfaction of eigenfunction including residual force vector term. Minimizing the cost functions of the difference between analytical and desired physical parameter matrices, the variations in parameter matrices are straightforwardly derived without using any multipliers. The validity of the proposed methods is evaluated in an application.

Structural Parameter Identification Based on Equivalent Single Degree Systems

2010 ◽  
Vol 450 ◽  
pp. 510-513
Author(s):  
Yan Wei Wang ◽  
Zi Fa Wang ◽  
Rui Zhi Wen
Keyword(s):  
Numerical Simulation ◽  
Differential Evolution ◽  
Parameter Identification ◽  
Physical Parameter ◽  
Optimization Algorithm ◽  
New Method ◽  
Structural Parameter ◽  
Physical Parameters ◽  
Single Degree

In order to solve the problems of optimization algorithm used to identify the physical parameters of structures, a new method based on a series of equivalent single degree systems is proposed in this paper. The key idea of the method is that a multi-degree system can be represented by a series of single degree systems that can be identified one by one to perform the identification of the whole system. This method can not only decrease the dimensions of optimization algorithm, but also reduce the amount of estimation work in searching for the bound of parameters, and at the same time improve the identification results when parameters might suddenly change. In the numerical simulation of the physical parameter identification of a multi-degree system, Differential evolution is one of the optimization algorithm methods which are used to identify a series of equivalent single degree systems instead of the multi-degree system they represent, and the identification results prove that the method proposed in this paper is valid.

scholarly journals A New Physical Parameter Identification Method for Two-Axis On-Road Vehicles: Simulation and Experiment

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Minyi Zheng ◽  
Peng Peng ◽  
Bangji Zhang ◽  
Nong Zhang ◽  
Lifu Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Parameter Identification ◽  
Physical Parameter ◽  
Mass Matrix ◽  
Estimation Method ◽  
Least Square Method ◽  
Least Square ◽  
Percentage Error ◽  
Physical Parameters ◽  
Identification Method

A new physical parameter identification method for two-axis on-road vehicle is presented. The modal parameters of vehicle are identified by using the State Variable Method. To make it possible to determine the matricesM,C, andKof the vehicle, a known mass matrixΔMis designed to add into the vehicle in order to increase the number of equations ensuring that the number of equations is more than the one of unknowns. Therefore, the physical parameters of vehicle can be estimated by using the least square method. To validate the presented method, a numerical simulation example and an experiment example are given in this paper. The numerical simulation example shows that the largest of absolute value of percentage error is 1.493%. In the experiment example, a school bus is employed in study for the parameter identification. The simulation result from full-car model with the estimated physical parameters is compared with the test result. The agreement between the simulation and the test proves the effectiveness of the proposed estimation method.

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