Uncertainty Analysis on Vehicle-Bridge System with Correlative Interval Variables Based on Multidimensional Parallelepiped Model

2018 ◽  
Vol 15 (05) ◽  
pp. 1850030 ◽  
Author(s):  
Van Huy Truong ◽  
Jie Liu ◽  
Xianghua Meng ◽  
Chao Jiang ◽  
Trong Tien Nguyen
Keyword(s):  
Dynamic Response ◽  
Uncertainty Analysis ◽  
Great Influence ◽  
Upper And Lower Bounds ◽  
Analysis Method ◽  
Partial Difference ◽  
Interval Analysis Method ◽  
Interval Variables ◽  
Multidimensional Parallelepiped Model ◽  
Bridge System

For vehicle-bridge system, structural uncertainties, especially the interval variables with correlation, have a great influence on dynamic response. Therefore, this paper proposes an effective uncertainty analysis method for vehicle-bridge system based on multidimensional parallelepiped (MP) model, which can reasonably deal with the correlation of interval variables. First, the vehicle-bridge system is simplified as a four degrees-of-freedom mass-spring vehicle model running on a simply supported beam. MP model is adopted to describe the uncertainties of all the interval variables. Second, via affine coordinate system transform, the interval variables with correlation are transformed as the independent variables, which is very convenient for uncertainty analysis. Finally, the uncertain dynamic response is approximated through the first-order Taylor interval expansion, and the upper and lower bounds can be calculated using the dynamic response at midpoints and the partial difference multiplied by interval radius. Because the correlation is sufficiently considered, the uncertainty analysis results on vehicle–bridge interaction system will be much more accurate than the traditional interval analysis method (IAM). Numerical example demonstrates the correctness and effectiveness of the proposed method.

scholarly journals Evaluation of Wind-Induced Response Bounds of High-Rise Buildings Based on a Nonrandom Interval Analysis Method

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xianglei Wei ◽  
An Xu ◽  
Ruohong Zhao
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Wind Load ◽  
Upper And Lower Bounds ◽  
Induced Response ◽  
Response Analysis ◽  
Analysis Method ◽  
High Rise ◽  
Interval Analysis Method

The traditional wind-induced response analysis of high-rise buildings conventionally considers the wind load as a stationary stochastic process. That is, for a certain wind direction angle, the reference wind speed (usually refers to the mean wind speed at the building height) is assumed to be a constant corresponding to a certain return period. Combined with the recorded data in wind tunnel test, the structural response can be computed using the random vibration theory. However, in the actual typhoon process, the average wind speed is usually time-variant. This paper combines the interval process model and the nonrandom vibration analysis method with the wind tunnel test and proposes a method for estimating the response boundary of the high-rise buildings under nonstationary wind loads. With the given upper and lower bounds of time-variant wind excitation, this method can provide an effective calculation tool for estimating wind-induced vibration bounds for high-rise buildings under nonstationary wind load. The Guangzhou East tower, which is 530 m high and the highest supertall building in Guangzhou, China, was taken as an example to show the effectiveness of the method. The obtained boundary response can help disaster prevention and control during the passage of typhoons.

A Robust Aerodynamic Optimization Design for Airfoil Based on Interval Uncertainty Analysis Method

2019 ◽  
Author(s):  
Xin Song ◽  
Guannan Zheng ◽  
Guowei Yang
Keyword(s):  
Robust Optimization ◽  
Interval Analysis ◽  
Optimization Design ◽  
Aerodynamic Force ◽  
Interval Uncertainty ◽  
Upper And Lower Bounds ◽  
Analysis Method ◽  
Geometric Uncertainties ◽  
Interval Analysis Method ◽  
Robust Optimization Design

Abstract Uncertainties will make aircraft deviate from the designed condition, resulting in the decrease in aerodynamic performance and even destruction. This paper presents a fast nonlinear interval analysis method considering geometric uncertainties. DFFD method is used to parameterize the airfoil shape, and the Kriging model for aerodynamic force and uncertainty variables is optimized by PSO algorithm to find the upper and lower bounds of the objective interval. The effects of geometric uncertainties on NACA0012 airfoil are analyzed using the above method. And then, a robust optimization design method is established based on the interval analysis method. FFD method is used to produce the deterministic design variables and the order relation of interval number is employed to transform the uncertain optimization to deterministic multi-objective optimization which is solved by MOPSO based on Pareto entropy. The robust optimization design is implemented for the symmetrical airfoil with the drag objective under geometric uncertainties and thickness constraint, and the results are compared with the deterministic optimization to validate the effectiveness of the developed method.

Interval Analysis Method of Uncertain Structural Systems Based on Random Model

2011 ◽  
Vol 291-294 ◽  
pp. 3180-3185
Author(s):  
Zhao Wang ◽  
Min Huang
Keyword(s):  
Confidence Interval ◽  
Interval Analysis ◽  
Structural Response ◽  
Random Model ◽  
Structural Systems ◽  
Analysis Method ◽  
The Finite Element Method ◽  
Analysis And Design ◽  
Interval Analysis Method ◽  
Interval Variables

The uncertain parameters of the structures are expressed by interval variables, and the governed equations of the structural system are obtained with the finite element method, then interval analysis is used to model the uncertainty in the static structural analysis and design. After the interval arithmetic integrated with random theory is studied, the confidence interval of structural response is achieved, and the approximate calculation is used with the method of Monte Carlo. Furthermore, by combining the interval variable of the structural response with confidence interval, an analysis method of uncertain structural systems is proposed based on the random model. The presented method can restrain expanding interval, and easy to engineering due to its convenient calculation.

Dynamic Response Analysis of Rotor System With Uncertain Parameters via Interval Analysis Method

2012 ◽  
Author(s):  
Jie Hong ◽  
Jun Wang ◽  
Meng Chen ◽  
Yanhong Ma
Keyword(s):  
Dynamic Response ◽  
Interval Analysis ◽  
Operating Conditions ◽  
Response Analysis ◽  
Superposition Method ◽  
Uncertain Parameters ◽  
Analysis Method ◽  
Operating Cycle ◽  
Interval Analysis Method ◽  
Modal Superposition

The support stiffness and connecting structure stiffness change with different assembly conditions and operating conditions. The phase and amount of rotor unbalance in different operating cycle changes due to wear of blade tip and connecting structures in different working cycles. These parameters which have significant effect on rotordynamics are “uncertain but bounded”, in another word, the distributions of the parameters are unknown, but the intervals of uncertain parameters are always got easier. An interval analysis method, which solves the dynamic response with these uncertain parameters, has presented. Based on interval mathematics and modal superposition method, interval analysis method simplifies the uncertain parameters to interval vectors so that it can get the intervals within which the dynamic response varies when less information of structure is known. The interval analysis method is efficient under the condition that probability approach cannot work because of small samples and sparse statistics characteristics. The formulation of rotor dynamic response using interval modal superposition analysis method is formulated. A numerical example of comparison between interval analysis method and Monte Carlo method is given, and the results illustrate the interval analysis method.

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