A novel uncertainty analysis method for composite structures with mixed uncertainties including random and interval variables

2018 ◽  
Vol 184 ◽  
pp. 400-410 ◽  
Author(s):  
Xiao Chen ◽  
Zhiping Qiu
Keyword(s):  
Uncertainty Analysis ◽  
Composite Structures ◽  
Analysis Method ◽  
Interval Variables ◽  
Mixed Uncertainties

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 An Efficient Time-Variant Reliability Analysis Method with Mixed Uncertainties

Algorithms ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 229
Author(s):  
Fangyi Li ◽  
Yufei Yan ◽  
Jianhua Rong ◽  
Houyao Zhu
Keyword(s):  
Reliability Analysis ◽  
Limit State ◽  
Random Variables ◽  
Equivalent Model ◽  
Independent Random Variables ◽  
Problem Analysis ◽  
Analysis Method ◽  
Calculation Algorithm ◽  
Reliability Problem ◽  
Interval Variables

In practical engineering, due to the lack of information, it is impossible to accurately determine the distribution of all variables. Therefore, time-variant reliability problems with both random and interval variables may be encountered. However, this kind of problem usually involves a complex multilevel nested optimization problem, which leads to a substantial computational burden, and it is difficult to meet the requirements of complex engineering problem analysis. This study proposes a decoupling strategy to efficiently analyze the time-variant reliability based on the mixed uncertainty model. The interval variables are treated with independent random variables that are uniformly distributed in their respective intervals. Then the time-variant reliability-equivalent model, containing only random variables, is established, to avoid multi-layer nesting optimization. The stochastic process is first discretized to obtain several static limit state functions at different times. The time-variant reliability problem is changed into the conventional time-invariant system reliability problem. First order reliability analysis method (FORM) is used to analyze the reliability of each time. Thus, an efficient and robust convergence hybrid time-variant reliability calculation algorithm is proposed based on the equivalent model. Finally, numerical examples shows the effectiveness of the proposed method.

Uncertainty analysis of composite structures

2000 ◽  
Vol 185 (2-4) ◽  
pp. 413-432 ◽  
Author(s):  
Ahmed K. Noor ◽  
James H. Starnes ◽  
Jeanne M. Peters
Keyword(s):  
Uncertainty Analysis ◽  
Composite Structures

scholarly journals Uncertainty analysis based on sensitivity applied to angle-ply composite structures

2007 ◽  
Vol 92 (10) ◽  
pp. 1353-1362 ◽  
Author(s):  
Carlos Conceição António ◽  
Luísa N. Hoffbauer
Keyword(s):  
Uncertainty Analysis ◽  
Composite Structures

An Uncertainty Analysis Method for Coordinate Referencing in Manufacturing Systems

1995 ◽  
Vol 117 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Y. Shen ◽  
N. A. Duffie
Keyword(s):  
Uncertainty Analysis ◽  
Coordinate Transformation ◽  
Manufacturing Systems ◽  
Coordinate Transformations ◽  
Analysis Method ◽  
Uncertainty Interval ◽  
Coordinate Measurement ◽  
Uncertainty Sources ◽  
Design And Manufacturing ◽  
Coordinate Measurements

Accurate and consistent transformations between design and manufacturing coordinate systems are essential for high quality part production. Fixturing and coordinate measurement are common coordinate referencing techniques which are used to locate points or measurement points on workpiece reference surfaces to establish these coordinate transformations. However, uncertainty sources such as geometric form deviations in workpiece surfaces, tolerances on fixture locators, and errors in coordinate measurements exist. A result is that coordinate transformations established using the locating and measurement points are in herently uncertain. An uncertainty analysis method for coordinate referencing is presented in this paper. The uncertainty interval concept is used to describe essential characteristics of uncertainty sources in coordinate referencing and coordinate transformation relationships. The method is applied to estimating uncertainties in simple and compound coordinate transformation obtained using coordinate referencing in an experimental mold manufacturing system. Results of Monte Carlo simulations are used to show that the uncertainty analysis method gives a consistent and high percentage of coverage in evaluating coordinate referencing in the examples studied.

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