Modified Interval Perturbation Finite Element Method for a Structural-Acoustic System With Interval Parameters

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Baizhan Xia ◽  
Dejie Yu

For the frequency response analysis of the structural-acoustic system with interval parameters, a modified interval perturbation finite element method (MIPFEM) is proposed. In the proposed method, the interval dynamic equilibrium equation of the uncertain structural-acoustic system is established. The interval structural-acoustic dynamic stiffness matrix and the interval force vector are expanded by using the first-order Taylor series; the inversion of the invertible interval structural-acoustic dynamic stiffness matrix is approximated by employing a modified approximate interval-value Sherman–Morrison–Woodbury formula. The proposed method is implemented at an element-by-element level in the finite element framework. Numerical results on a shell structural-acoustic system with interval parameters verify the accuracy and efficiency of the proposed method.

Author(s):  
Ning Chen ◽  
Jiaojiao Chen ◽  
Jian Liu ◽  
Dejie Yu ◽  
Hui Yin

For the periodical composite structural-acoustic system with multi-scale interval uncertainties, a new interval analysis approach is presented in this study. In periodical composites structural-acoustic systems with multi-scale interval parameters, the variation ranges of the sound pressure response can be calculated using the homogenization-based interval finite element method. However, the homogenization-based interval finite element method that is based on Taylor series can only suit periodical composites structural-acoustic problems with small uncertainty degree. To consider larger uncertainty degree, by combining the Chebyshev polynomial series and the homogenization-based finite element, a homogenization-based Chebyshev interval finite element method is presented to predict the sound pressure responses of the structural-acoustic system involving periodical composite and multi-scale interval parameters. Compared with homogenization-based interval finite element method, homogenization-based Chebyshev interval finite element method can obtain higher accurate numerical solutions in the approximate process. Besides, homogenization-based Chebyshev interval finite element method can be implemented without conducting the complex derivation process. Numerical results verify the validity and practicability of the presented homogenization-based Chebyshev interval finite element method for the periodical composite structural-acoustic problem.


Author(s):  
W. Q. Feng ◽  
T. C. Huang ◽  
W. J. Liu ◽  
G. X. Dong

Abstract By the use of the extended finite element method the analysis of the random response of a linear structure to a continuous excitation field, random in time and space, is presented in this paper. The extended finite element method includes the formulation for obtaining the equivalent node force power spectrum. The corresponding computer program has been produced. A random response analysis of a sluice gate support shows satisfactory agreement with the experiment results.


2020 ◽  
Vol 20 (07) ◽  
pp. 2071006
Author(s):  
Jin Zhang ◽  
Zejun Han ◽  
Hongyuan Fang ◽  
Linqing Yang

The interaction between underground pipelines and soils is crucial to the design and maintenance of underground pipeline network systems. In this paper, the dynamic stiffness matrix in the frequency-domain of the buried pipeline is obtained by the improved scaled boundary finite element method (SBFEM) coupled with the finite element method (FEM) at the interface between the far and near fields. A new coordinate transformation together with a scaled line is introduced in the improved SBFEM. Combined with the mixed variable algorithm, the time-domain solution of the buried pipeline under dynamic loads is then obtained. The accuracy of the proposed algorithm was verified by numerical examples. A parametric study is performed to assess the influence of the anisotropic characteristics of the layered soils on the dynamic response of the pipeline, the result of which provides a reliable basis for engineering practice. The results show that these parameters have a significant impact on the pipeline. The understanding of this impact can contribute to the design, construction, and maintenance of the corresponding engineering projects.


Author(s):  
Yuan Jie Lua ◽  
Robert H. Sues

Mechanistic pavement analysis and design based on either layered elastic analysis (LEA) or the finite element method (FEM) is increasingly being used to replace the empirical design process. The simplifying assumptions of a uniform, homogeneous layer of linear material used in LEA can render its analysis inaccurate for real pavement structures. The FEM is more attractive for structural analysis of pavements; the generality of the FEM also allows both the use of comprehensive material models and modeling of the spatial variability that exists in pavement systems. To date, spatial variability and uncertainty are ignored in pavement system finite element analyses. Ignoring spatial variability and uncertainty implies a false sense of accuracy in the results and can lead to inaccurate assessment of the pavement. The first application of the probabilistic finite element method to pavement response analysis and life prediction and the first investigation of the effects of spatial variability on pavement life prediction are presented. It is concluded that the probabilistic FEA, with spatial variability, is a more accurate representation of the true physical condition and leads to results that are less conservative than those obtained with probabilistic LEA.


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