scholarly journals Modeling and Stochastic Model Updating of Bolt-Jointed Structure

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Ming Zhan ◽  
Qintao Guo ◽  
Lin Yue ◽  
Baoqiang Zhang
Keyword(s):  
Finite Element ◽  
High Resolution ◽  
Material Properties ◽  
Model Updating ◽  
Computational Cost ◽  
Three Dimensional ◽  
Element Model ◽  
Joint Interface ◽  
Unknown Parameters ◽  
Updating Procedure

Bolt-jointed structure is widely used in engineering fields. The dynamic characteristics of bolt-jointed structure are complex, and there is a variety of uncertainties in the jointed structure. In this study, modeling and updating of a typical bolt-jointed structure are investigated. In modeling terms, three-dimensional brick elements are used to represent the substructures, and thin-layer elements with virtual material properties are employed to represent the joint interface. Modal tests and experimental modal analysis of substructures and built-up structure are performed. A hierarchical model updating strategy based on Bayesian inference is applied to identify the unknown parameters in the substructures model and those in the overall model. Radial basis function (RBF) models are used as surrogates of time-consuming finite element model with high resolution to avoid the enormous computational cost. The results indicate that the updated model can reproduce modal frequencies used in updating and can predict those not used in the updating procedure.

scholarly journals Model Updating Method Based on Kriging Model for Structural Dynamics

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Hong Yin ◽  
Jingjing Ma ◽  
Kangli Dong ◽  
Zhenrui Peng ◽  
Pan Cui ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frequency Response ◽  
Structural Dynamics ◽  
Model Updating ◽  
Computational Cost ◽  
Element Model ◽  
Kriging Model ◽  
Surface Model ◽  
Sample Points

Model updating in structural dynamics has attracted much attention in recent decades. And high computational cost is frequently encountered during model updating. Surrogate model has attracted considerable attention for saving computational cost in finite element model updating (FEMU). In this study, a model updating method using frequency response function (FRF) based on Kriging model is proposed. The optimal excitation point is selected by using modal participation criterion. Initial sample points are chosen via design of experiment (DOE), and Kriging model is built using the corresponding acceleration frequency response functions. Then, Kriging model is improved via new sample points using mean square error (MSE) criterion and is used to replace the finite element model to participate in optimization. Cuckoo algorithm is used to obtain the updating parameters, where the objective function with the minimum frequency response deviation is constructed. And the proposed method is applied to a plane truss model FEMU, and the results are compared with those by the second-order response surface model (RSM) and the radial basis function model (RBF). The analysis results showed that the proposed method has good accuracy and high computational efficiency; errors of updating parameters are less than 0.2%; damage identification is with high precision. After updating, the curves of real and imaginary parts of acceleration FRF are in good agreement with the real ones.

scholarly journals Determination of Material/Geometry of the Section Most Adequate for a Static Loaded Beam Subjected to a Combination of Bending and Torsion

2012 ◽  
Vol 730-732 ◽  
pp. 507-512 ◽  
Author(s):  
Hugo Miguel Silva ◽  
José Filipe Bizarro de Meireles
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Model Updating ◽  
Material Selection ◽  
Young Modulus ◽  
Element Model ◽  
Mechanical Tests ◽  
Correct Operation ◽  
Short Period ◽  
Relevant Material

The acceleration of industrial machines mobile parts has been increasing over the last few years, due to the need of higher production in a short period of time. The machines were dimensioned for a lower value of acceleration, which means there is not enough rigidity for the correct operation at much higher accelerations. Nowadays, the accelerations can be near 12 times the acceleration of gravity. There is the need of improving rigidity to make possible the correct machine operation without undesired vibrations that can ultimately lead to failure. The main applications of this work are plotters and laser cutting machines. To improve rigidity, one must improve the relevant material properties, and the relevant geometric variables of the model.[1] A novel Finite Element Model Updating methodology is presented in this paper. The considered models were : a ribbed plate and a tubular beam. The models were built by means of the Finite Element Method (FEM), and MATLAB was used to control the optimization process, using a programming code. Both material properties and geometric parameters were optimized. The main aim of the materials modeling is to know how the value of the objective function changes with the value of the material properties. Materials selection was performed, using material selection charts, to select the best material for the application. The value of these properties was not in the catalogue, and the properties used to perform the material selection were related to a material sub-class, Eg. Steel. The final material selection determined the best specific material for the application, and that material was mechanically tested. The mechanical tests performed were: Tensile Test and Extensometry Test, to obtain the relevant material properties, mainly Young Modulus, Poisson Coefficient and Yield Stress. The deflection of the optimized models reduced strongly in comparison to the initial models.

scholarly journals A Mix-resolution Bone-related Statistical Deformable Model (mBr-SDM) for Soft Tissue Prediction in Orthognathic Surgery Planning

2008 ◽  
Author(s):  
He Qizhen ◽  
Ip Horace ◽  
James Xia
Keyword(s):  
Finite Element ◽  
High Resolution ◽  
Orthognathic Surgery ◽  
Computational Cost ◽  
Element Model ◽  
Regions Of Interest ◽  
Deformable Model ◽  
Deformation Region ◽  
Low Computational Cost ◽  
Main Deformation

In this paper, we propose a Mix-resolution Bone-related Statistical Deformable Model (mBr-SDM) to improve the predicting accuracy of orthognathic surgery, particularly for the main deformation region. Mix-resolution Br-SDM consists of two separate Br-SDM of different resolutions: a high-resolution Br-SDM which is trained with more samples to capture the detail deforming variations in the main deforming regions of interest, together with a low-resolution Br-SDM which is trained with a smaller number of samples to capture the major variations of the remaining facial points. The experiments have shown that the mix-resolution Br-SDM is able to significantly reduce the predicting error compared with the corresponding Finite Element Model, while giving a low computational cost which is characteristic of the SDM approach.

Highly Efficient Probabilistic Finite Element Model Updating Using Intelligent Inference With Incomplete Modal Information

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
K. Zhou ◽  
J. Tang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Computational Cost ◽  
Sampling Technique ◽  
Element Model ◽  
Measurement Information ◽  
Model Parameters ◽  
Finite Element Model Updating ◽  
Highly Efficient

A highly efficient probabilistic framework of finite element model updating in the presence of measurement noise/uncertainty using intelligent inference is presented. This framework uses incomplete modal measurement information as input and is built upon the Bayesian inference approach. To alleviate the computational cost, Metropolis–Hastings Markov chain Monte Carlo (MH MCMC) is adopted to reduce the size of samples required for repeated finite element modal analyses. Since adopting such a sampling technique in Bayesian model updating usually yields a sparse posterior probability density function (PDF) over the reduced parametric space, Gaussian process (GP) is then incorporated in order to enrich analysis results that can lead to a comprehensive posterior PDF. The PDF obtained with densely distributed data points allows us to find the most optimal model parameters with high fidelity. To facilitate the entire model updating process with automation, the algorithm is implemented under ansys Parametric Design Language (apdl) in ansys environment. The effectiveness of the new framework is demonstrated via systematic case studies.

scholarly journals Finite Element Analysis of a Ribbed Roofing Panel under Static Flexure

2018 ◽  
Vol 3 (6) ◽  
pp. 15
Author(s):  
Chinedum Vincent Okafor
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Load Carrying ◽  
Dimensional Finite Element ◽  
Linear Material ◽  
Three Dimensional Finite Element ◽  
Static Conditions

This study focuses on analyzing the response of a typical ribbed aluminum panel under flexure. A three dimensional finite element model was developed to stimulate the static flexure behavior. The model is a 2.0m (length) x 1.0m (width) x 0.005m (Thickness) with a rib height of 0.038m, crest width of 0.019m and pan distance at 0.055m between intermediate ribs. The load deflection response of the aluminum panel under different flexural loading condition was stimulated. The linear material properties, displacement, stress and strain captured were discussed under static conditions. From the result obtained, the maximum uniformly distributed load carrying capacity of the ribbed aluminum roofing panel under flexure, considering the linear material properties is 665N.

scholarly journals Structural model updating based on metamodel using modal frequencies

2021 ◽  
Vol 15 (58) ◽  
pp. 114-127
Author(s):  
Jutao Wang ◽  
Zhenzhong Liu ◽  
Liju Xue
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Model ◽  
Model Updating ◽  
Element Model ◽  
Kriging Model ◽  
Frame Structure ◽  
Updating Procedure ◽  
The Finite Element Model

Modal frequencies are often used in structural model updating based on the finite element model, and metamodel technique is often applied to the corresponding optimization process. In this work, the Kriging model is used as the metamodel. Firstly, the influence of different correlation functions of Kriging model is inspected, and then the approximate capability of Kriging model is investigated via inspecting the approximate accuracy of nonlinear functions. Secondly, a model updating procedure is proposed based on the Kriging model, and the samples for constructing Kriging model are generated via the method of Optimal Latin Hypercube. Finally, a typical frame structure is taken as a case study and demonstrates the feasibility and efficiency of the proposed approach. The results show the Kriging model can match the target functions very well, and the finite element model can achieve accurate frequencies and can reliably predict the frequencies after model updating.

Investigation on the traveling wave and three-dimensional trajectory of motion on the stator of rotational ultrasonic motors

2020 ◽  
Vol 64 (1-4) ◽  
pp. 631-638
Author(s):  
Hucheng Chen ◽  
Wei Han ◽  
Jinhao Qiu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Traveling Wave ◽  
Dimensional Space ◽  
Computational Cost ◽  
Three Dimensional ◽  
Element Model ◽  
Input Voltage ◽  
Ultrasonic Motors ◽  
And Performance

Better understanding of the characteristics of the traveling wave and three-dimensional trajectory related to motion on the surface of the stator is very important for the design and performance improvement of the ultrasonic motors. In this paper, an accurate finite element model of a single stator with a fully coupled piezoelectric layer was established at a moderate computational cost. The finite element model was verified by experimental test at the inverse resonance point. Based on this model, the traveling wave and three-dimensional trajectory of stator surface, including the influence of the input voltage on the phase and amplitude of the displacements in three directions, are investigated. The results show that the trajectory of particles on the stator surface is an ellipse in three-dimensional space due to the phase differences between the three components of displacement in the radial, circumferential and axial directions. The amplitude of radial displacement is about 39.5% of that in the circumferential displacement, which should not be neglected.

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