Dynamic Response Analysis of Stochastic Frame Structures Under Nonstationary Random Excitation

2006

A novel method (Fuzzy factor method) is presented, which is used in the dynamic response analysis of fuzzy stochastic truss structures under fuzzy stochastic step loads. Considering the fuzzy randomness of structural physical parameters, geometric dimensions and the amplitudes of step loads simultaneously, fuzzy stochastic dynamic response of the truss structures is developed using the mode superposition method and fuzzy factor method. The fuzzy numerical characteristics of dynamic response are then obtained by using the random variable's moment method and the algebra synthesis method. The influences of the fuzzy randomness of structural physical parameters, geometric dimensions and step load on the fuzzy randomness of the dynamic response are demonstrated via an engineering example, and MonteCarlo method is used to simulate this example, verifying the feasibility and validity of the modeling and method given in this paper.

Section: Fuzzy Stochastic Variables and Their Fuzzy Probabilistic Chamentioning

confidence: 99%

mentioning

confidence: 99%

Dynamic Response Analysis of Fuzzy Stochastic Truss Structures under Fuzzy Stochastic Excitation

Chen

2006

“…But uncertainties due to inaccurate measurement, the lack of experimental data and incomplete knowledge of the structure belong to fuzziness. In recent years, the structural analyses with uncertain parameters especially with random parameters have been reported extensively in the literatures [4][5][6][7][8][9]. Dimentberg and Naess [4] investigated short-term dynamic instability of a single-degree-of-freedom system with temporal random variations of its total apparent damping.…”

Section: Introductionmentioning

confidence: 99%

The analyses of dynamic response and reliability of fuzzy-random truss under stationary stochastic excitation

Wriggers

et al. 2010

A new two-factor method based on the probability and the fuzzy sets theory is used for the analyses of the dynamic response and reliability of fuzzy-random truss systems under the stationary stochastic excitation. Considering the fuzzy-randomness of the structural physical parameters and geometric dimensions simultaneously, the fuzzy-random correlation function matrix of structural displacement response in time domain and the fuzzy-random mean square values of structural dynamic response in frequency domain are developed by using the two-factor method, and the fuzzy numerical characteristics of dynamic responses are then derived. Based on numerical characteristics of structural fuzzy-random dynamic responses, the structural fuzzy-random dynamic reliability and its fuzzy numerical characteristic are obtained from the Poisson equation. The effects of the uncertainty of the structural parameters on structural dynamic response and reliability are

“…The most common approach to problems of uncertainty is to model the structural geometric and material parameters as random variables [5,6,14]. Under these circumstances, the mean value, variance, standard deviation of individual structural parameters and the correlation between different structural parameters are provided by the probabilistic information W. Gao School of Mechanical and Manufacturing Engineering, The University of New South Wales Sydney, NSW2052, Australia E-mail: w.gao@unsw.edu.au (W. Gao) Tel.…”

Section: Introductionmentioning

confidence: 99%

Interval Finite Element Analysis using Interval Factor Method

2006

A new method called the interval factor method for the finite element analysis of truss structures with interval parameters is presented in this paper. The structural parameters and applied forces can be considered as interval variables by using the interval factor method, the structural stiffness matrix can then be divided into the product of two parts corresponding to the interval factors and the deterministic value. From the static governing equations of interval finite element method of structures, the structural displacement and stress responses are expressed as the functions of the interval factors. The computational expressions for lower and upper bounds, mean value and interval change ratio of structural static responses are derived by means of the interval operations. The effect of the uncertainty of the structural parameters and applied forces on the structural displacement and stress responses is demonstrated by truss structures.