Nonstationary Random Response Analysis of Spatially Stochastic Structures Without Applying Probabilistic Finite Elements

2000 ◽  
Author(s):  
C. W. S. To
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Elements ◽  
Response Analysis ◽  
Structural Systems ◽  
Random Response ◽  
Central Difference ◽  
Central Difference Method ◽  
Random Responses ◽  
First Time

Abstract A procedure based on the stochastic central difference method that was presented earlier by the author has been extended to cases involving with spatially and temporally stochastic structural systems that are approximated by the versatile finite element method. It is believed that for the first time nonstationary random responses of this class of systems are considered. The procedure eliminates the limitations associated with those employing the so-called stochastic or probabilistic finite element methods. Owing to its simplicity, the proposed method can easily be incorporated into many commercially available finite element packages.

Random Response Analysis for Nonlinear Systems of Composite Laminates

2011 ◽  
Vol 415-417 ◽  
pp. 56-61
Author(s):  
Feng Xiang You ◽  
Fei Zhang ◽  
Buo Lei Zuo
Keyword(s):  
Nonlinear Systems ◽  
Composite Laminates ◽  
Response Analysis ◽  
Random Response ◽  
Random Parameters ◽  
Engineering Structures ◽  
Central Difference ◽  
Central Difference Method ◽  
Random Responses ◽  
Random Nature

Geometric parameters of composite materials often have a random nature in engineering structures. How to study random response and statistical properties of nonlinear systems with random parameters has a very important significance for reliability and optimization of structural design. In this paper, perturbation method and random central difference method are explored to establish composite nonlinear vibration equations and computational model to study random responses of nonlinear systems with random parameters under deterministic loading of the composite laminates, numerical examples illustrate the correctness of the algorithm.

Random Response of a Sluice Gate Support

1991 ◽  
Author(s):  
W. Q. Feng ◽  
T. C. Huang ◽  
W. J. Liu ◽  
G. X. Dong
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Extended Finite Element Method ◽  
Linear Structure ◽  
Response Analysis ◽  
Random Response ◽  
Extended Finite Element ◽  
Sluice Gate ◽  
Excitation Field ◽  
Element Method

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.

Damage Identification for Curl Tube Structure Based on Modal Flexibility Curvature

2012 ◽  
Vol 490-495 ◽  
pp. 2151-2155
Author(s):  
Yong Jun Li ◽  
Li Yuan Ma ◽  
Tian Hui Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Damage Identification ◽  
Vertical Plane ◽  
The Finite Element Method ◽  
Central Difference ◽  
Damage Location ◽  
Modal Flexibility ◽  
Central Difference Method ◽  
Tube Structure

To detect the damage of curl tube structure with more effect, the finite element method (FEM) and experimental modal analysis (EMA) were employeed to generate the modal flexibility of the curl tube. The modal flexibility was used to compute the modal flexibility-curvature by using the central difference method. Different degrees and locations of damage were simulated by additional quality in the intact curl tube to verify the modal flexibility-curvature and difference generated by both FEM and EMA. The results show that the modal flexibility of curl tube should have the direction. In addition, we conclude that the flexibility curvature’s difference in x and y plane can not be used for damage identification. But using the flexibility curvature’s difference of the z direction in the vertical plane, we can not only identified the multiple damage location, but also to analized degree for the extent of injury to the same location .

AN EXPLICIT SMOOTHED FINITE ELEMENT METHOD (SFEM) FOR ELASTIC DYNAMIC PROBLEMS

2013 ◽  
Vol 10 (01) ◽  
pp. 1340002 ◽  
Author(s):  
X. Y. CUI ◽  
G. Y. LI ◽  
G. R. LIU
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Time Integration ◽  
Internal Force ◽  
Dynamic Problems ◽  
Central Difference ◽  
Strain Smoothing ◽  
Smoothed Finite Element Method ◽  
Central Difference Method ◽  
Element Method

This paper presents an explicit smoothed finite element method (SFEM) for elastic dynamic problems. The central difference method for time integration will be used in presented formulations. A simple but general contact searching algorithm is used to treat the contact interface and an algorithm for the contact force is presented. In present method, the problem domain is first divided into elements as in the finite element method (FEM), and the elements are further subdivided into several smoothing cells. Cell-wise strain smoothing operations are used to obtain the stresses, which are constants in each smoothing cells. Area integration over the smoothing cell becomes line integration along its edges, and no gradient of shape functions is involved in computing the field gradients nor in forming the internal force. No mapping or coordinate transformation is necessary so that the element can be used effectively for large deformation problems. Through several examples, the simplicity, efficiency and reliability of the smoothed finite element method are demonstrated.

scholarly journals Non-linearity of the contact layer between elements joined in a multi-bolted connection and the preload of the bolts

2016 ◽  
Vol 165 (2) ◽  
pp. 3-8
Author(s):  
Rafał GRZEJDA
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Elements ◽  
Cylinder Head ◽  
Contact Layer ◽  
Rigid Support ◽  
The Finite Element Method ◽  
Bolted Connection ◽  
Winkler Model ◽  
Engine Cylinder

The paper presents modeling and calculations of multi-bolted connections at the assembly stage on an example of the engine cylinder head-block connection. The physical model of the connection was introduced as a combination of three subsystems: the set of bolts, the joined element and the contact layer between the joined element and the rigid support. The finite element method (FEM) was used for the modeling. Bolts were replaced with hybrid elements. The joined element was modeled with spatial finite elements. The Winkler model of the contact layer has been taken into consideration. The truth of the theorem has been examined, according to which non-linearity of the contact layer has a negligible impact on the final values of the bolt forces in the case of sequential preloading of the multi-bolted connection. The results of the calculations of a selected multi-bolted connection have been compared with the experimental results.

Probabilistic Finite-Element Analysis of Airfield Pavements

1996 ◽  
Vol 1540 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Yuan Jie Lua ◽  
Robert H. Sues
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Spatial Variability ◽  
Life Prediction ◽  
Homogeneous Layer ◽  
Response Analysis ◽  
Element Analysis ◽  
Analysis And Design ◽  
Pavement Structures ◽  
Element Method

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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