A high-frequency open boundary for transient seepage analyses of semi-infinite layers by extending the scaled boundary finite element method

2015 ◽  
Vol 40 (6) ◽  
pp. 919-941 ◽  
Author(s):  
Suriyon Prempramote
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Frequency ◽  
Open Boundary ◽  
Transient Seepage ◽  
Scaled Boundary Finite Element ◽  
Seepage Analyses ◽  
Element Method

Scaled Boundary Finite Element Method for Modeling of Impedance Based Structural Health Monitoring of 2D Structure

2018 ◽  
Author(s):  
Naserodin Sepehry ◽  
Firooz Bakhtiari-Nejad ◽  
Weidong Zhu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
High Frequency ◽  
Frequency Method ◽  
Structural Health ◽  
2D Structure ◽  
Scaled Boundary Finite Element ◽  
Element Method

Impedance based structural health monitoring using piezoelectric material is a high frequency method for detection of tiny damage. For modeling of structure in high frequency using conventional finite element method very fine mesh is needed. For large structure, this leads to very large mass and stiffness matrices. So very high RAM is needed to save these matrices and simulation time would be very low. In this paper a method combined finite element method and boundary element method named scaled boundary finite element method is studied for health and cracked 2D structure. Impedance of healthy and cracked structure is compared and verified by finite element method. A good agreement is presented and very low degree of freedom is obtained compared with finite element method.

Application of scaled boundary finite element method for vibration-based structural health monitoring of breathing cracks

2020 ◽  
pp. 107754632096864
Author(s):  
Naserodin Sepehry ◽  
Mohammad Ehsani ◽  
Weidong Zhu ◽  
Firooz Bakhtiari-Nejad
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
High Frequency ◽  
Power Efficiency ◽  
Breathing Crack ◽  
Structural Health ◽  
Scaled Boundary Finite Element ◽  
Element Method

The dynamic response of the host structure to a high-frequency actuation is usually used for the detection of tiny damage in structures in the form of breathing crack. The simulation of the microcrack’s effect on the response is essential for several damage identification targets. The conventional finite element method suffers from very small mesh size requirements to address the high-frequency problems, resulting in very large mass and stiffness matrices. In this study, the scaled boundary finite element method was applied to model different schemes of structural health monitoring of a structure with breathing cracks based on high-frequency vibration. The scaled boundary finite element method discretizes only the boundary of the model and thus substantially reduces the size of structural matrices. The node-to-node contact strategy was introduced to the scaled boundary finite element method to capture the contact problem that occurs during the vibration of the breathing crack. As breathing crack vibration results in some nonlinear effects, the simulation of three phenomena was of interest: higher harmonic generation, frequency shift, and vibro-acoustic modulation. A shooting method was used for efficient time integration and description of the frequency response function in the nonlinear regime. According to the results, the scaled boundary finite element method is of great power, efficiency, and accuracy to treat the contact problems, especially in high-frequency regimes. Moreover, the nonlinear methods provide certain advantages over the linear techniques in the early detection of incipient damage.

A Coupled SBFEM-FEM Approach for Evaluating Stress Intensity Factors

2013 ◽  
Vol 353-356 ◽  
pp. 3369-3377 ◽  
Author(s):  
Ming Guang Shi ◽  
Chong Ming Song ◽  
Hong Zhong ◽  
Yan Jie Xu ◽  
Chu Han Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Geometry ◽  
Stress Singularity ◽  
Intensity Factors ◽  
Finite Element Software ◽  
Scaled Boundary Finite Element ◽  
Element Method

A coupled method between the Scaled Boundary Finite Element Method (SBFEM) and Finite Element Method (FEM) for evaluating the Stress Intensity Factors (SIFs) is presented and achieved on the platform of the commercial finite element software ABAQUS by using Python as the programming language. Automatic transformation of the finite elements around a singular point to a scaled boundary finite element subdomain is realized. This method combines the high accuracy of the SBFEM in computing the SIFs with the ability to handle material nonlinearity as well as powerful mesh generation and post processing ability of commercial FEM software. The validity and accuracy of the method is verified by analysis of several benchmark problems. The coupled algorithm shows a good converging performance, and with minimum additional treatment can be able to handle more problems that cannot be solved by either SBFEM or FEM itself. For fracture problems, it proposes an efficient way to represent stress singularity for problems with complex geometry, loading condition or certain nonlinearity.

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