Evaluating J -integral and Q parameter in high-density polyethylene using a combined experimental finite element method

2016 ◽  
Vol 40 (6) ◽  
pp. 924-938 ◽  
Author(s):  
M Sahlabadi ◽  
A Valiollahi ◽  
B Konh ◽  
N Soltani
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Density Polyethylene ◽  
High Density ◽  
J Integral ◽  
Element Method

A Tunable THz Plasmonic Waveguide Based on Graphene Coated Bow-tie Nanowire with High Mode Confinement

2020 ◽  
Vol 12 ◽  
Author(s):  
Jue Wang ◽  
Tao Ma ◽  
Xu Wang ◽  
Fang Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Field ◽  
High Density ◽  
Plasmonic Waveguide ◽  
Field Distributions ◽  
Simulation Results ◽  
Photonic Circuit ◽  
Bow Tie ◽  
Element Method

Background: : A THz Plasmonic Waveguide Based on Graphene Coated Bow-tie Nanowire (TPW-GCBN) is proposed. The waveguide characteristics are investigated by using Finite Element Method (FEM). The influence of the geometric parameters on propagation constants, electric field distributions, effective mode areas, and propagation lengths are obtained numerically. The performance tunability of TPW-GCBN is also studied by adjusting the Fermi energy (FE). The simulation results show that the TPW-GCBN has better mode confinement ability. The TPW-GCBN has potential applications in high density integration of photonic circuit for the future tunable micro nano optoelectronic devices. Surface plasmon polaritons (SPPs) based waveguides have been widely used to enhance the local electric fields. It also has the capability of manipulating electromagnetic fields on the deep-subwavelength. Objective:: The waveguide characteristics of a THz Plasmonic Waveguide Based on Graphene Coated Bow-tie Nanowire (TPW-GCBN) should be investigated. The tunability of TPW-GCBN should be studied by adjusting the chemical potential (FE) which can be changed by the voltage. Method: : The mode analysis and parameter sweep in Finite Element Method (FEM) were used to simulate the TPW-GCBN for analyzing effective refractive index (neff), electric field distributions, normalized mode areas (Am), propagation length (Lp) and figure of merit (FoM). Results: : At 5 THz, Aeff of λ2/14812, Lp of ~2 μm and FoM of 25 can be achieved. The simulation results show that the TPW-GBN has good mode confinement ability and flexible tunability. Conclusion:: The TPW-GBN provides a new freedom to manipulate the graphene surface plasmons, and leads to new applications in high density integration of photonic circuit for tunable integrated optical devices.

scholarly journals Fracture Modelling of a Cracked Pressurized Cylindrical Structure by Using Extended Iso-Geometric Analysis (X-IGA)

Mathematics ◽  
2021 ◽  
Vol 9 (23) ◽  
pp. 2990
Author(s):  
Soufiane Montassir ◽  
Hassane Moustabchir ◽  
Ahmed Elkhalfi ◽  
Maria Luminita Scutaru ◽  
Sorin Vlase
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Extended Finite Element Method ◽  
Geometric Analysis ◽  
J Integral ◽  
Intensity Factors ◽  
Extended Finite Element ◽  
Matlab Code ◽  
Nurbs Basis Function ◽  
Element Method

In this study, a NURBS basis function-based extended iso-geometric analysis (X-IGA) has been implemented to simulate a two-dimensional crack in a pipe under uniform pressure using MATLAB code. Heaviside jump and asymptotic crack-tip enrichment functions are used to model the crack’s behaviour. The accuracy of this investigation was ensured with the stress intensity factors (SIFs) and the J-integral. The X-IGA—based SIFs of a 2-D pipe are compared using MATLAB code with the conventional finite element method available in ABAQUS FEA, and the extended finite element method is compared with a user-defined element. Therefore, the results demonstrate the possibility of using this technique as an alternative to other existing approaches to modeling cracked pipelines.

Combined Adaptive Finite Element Method and J-Domain Integral Technique for Crack Problems

2007 ◽  
Vol 340-341 ◽  
pp. 459-464
Author(s):  
Kobsak Potjananapasiri ◽  
Sutthisak Phongthanapanich ◽  
Paritud Bhandhubanyong ◽  
Pramote Dechaumphai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Tip ◽  
Adaptive Finite Element Method ◽  
J Integral ◽  
Adaptive Finite Element ◽  
Domain Integral ◽  
Integral Technique ◽  
Crack Problems ◽  
Element Method

An adaptive finite element method for analyzing two-dimensional and axisymmetric nonlinear elastic fracture mechanics problems with cracks is presented. The J-integral is used as a parameter to characterize the severity of stresses and deformation near a crack tip. The domain integral technique is utilized as the J-integral solution scheme with the 9-node degenerated crack tip elements. The solution accuracy is further improved by incorporating an error estimation procedure to a remeshing algorithm with a solution mapping scheme to resume the analysis at a particular load level after the adaptive remeshing technique has been applied. Two benchmark problems are analyzed to evaluate the efficiency of the combined procedure.

Fracture analysis of plastically graded material with thermo-mechanical J-integral

2021 ◽  
pp. 146442072199158
Author(s):  
Margi Gajjar ◽  
Himanshu Pathak
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Extended Finite Element Method ◽  
Isotropic Hardening ◽  
Fracture Parameter ◽  
J Integral ◽  
Extended Finite Element ◽  
Graded Material ◽  
Plastically Graded ◽  
Element Method

In this paper, the influence of plasticity graded property and thermal boundary conditions have been investigated on the fracture parameter, i.e. J-integral using the extended finite element method. A complete computational methodology has been presented to model elasto-plastic fracture problems with geometrical and material nonlinearities. For crack discontinuity modeling, a partition of unity enrichment concept was employed with additional mathematical functions like Heaviside and branch enrichment for crack discontinuity and stress field gradient, respectively. The modeling of the stress–strain relationship of the material is implemented using the Ramberg–Osgood material model and geometric nonlinearity is modeled using an updated Lagrangian approach. The isotropic hardening and von-Mises yield criteria are considered to check the plasticity condition. The elastic predictor–plastic corrector algorithm is employed to capture elasto-plastic stress in a cracked domain. The variation in plasticity properties for plastically graded material is modeled by exponential law. Furthermore, the nonlinear discrete equations are numerically solved using a Newton–Raphson iterative scheme. Various cracked problem geometries subjected to thermal (adiabatic and isothermal conditions) and thermo-mechanical loads are simulated for stress contours and J-integrals using the elasto-plastic fracture mechanics approach. A comparison of the results obtained using extended finite element method with literature and the finite element analysis (FEA) package shows the accuracy and effectiveness of the presented computational approach. A component-based problem, i.e. a Brazilian disc subjected to thermo-mechanical loading, has been solved to show the adaptability of this work.

scholarly journals On the Modified Monotonic Loading Concept for the Calculation of the Cyclic J-Integral

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Ross Beesley ◽  
Haofeng Chen ◽  
Martin Hughes
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Surface Crack ◽  
Accurate Method ◽  
Monotonic Loading ◽  
J Integral ◽  
Loading Conditions ◽  
Critical Crack ◽  
Plane Shear ◽  
Element Method

This paper investigates an approach for calculating the cyclic J-integral through a new industrial application. A previously proposed method is investigated further with the extension of this technique through a new application of a practical three-dimensional (3D) notched component containing a semi-elliptical surface crack. Current methods of calculating the cyclic J-integral are identified and their limitations discussed. A modified monotonic loading (MML) concept is adapted to calculate the cyclic J-integral of this 3D semi-elliptical surface crack under cyclic loading conditions. Both the finite element method (FEM) and the extended finite element method (XFEM) are discussed as possible methods of calculating the cyclic J-integral in this investigation. Different loading conditions including uniaxial tension and out-of-plane shear are applied, and the relationships between the applied loads and the cyclic J-integral are established. In addition, the variations of the cyclic J-integral along the crack front are investigated. This allows the determination of the critical load that can be applied before crack propagation occurs, as well as the identification of the critical crack direction once propagation does occur. These calculations display the applicability of the method to practical examples and illustrate an accurate method of estimating the cyclic J-integral.

scholarly journals A study on the accuracy of J-integral calculation by finite element method.

1988 ◽  
Vol 54 (504) ◽  
pp. 1623-1628
Author(s):  
Kikuo KISHIMOTO ◽  
Noriyasu TAKEUCHI ◽  
Shigeru AOKI ◽  
Masaru SAKATA
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
J Integral ◽  
Element Method
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