Fractal-like finite element method pdf

Siam journal on applied mathematics society for industrial. In this section, the methodology of the fractallike finite element method will be given. Abstractthe fractallike finite element method has been proved to be very efficient and accurate in twodimensional static and dynamic crack problems. Fractallike structure can be reached, using uniform distribution of these grains fig. In this paper, we extend our previous study to include. Abstractthe fractal like finite element method has been proved to be very efficient and accurate in twodimensional static and dynamic crack problems. Computation of the stress intensity factors of sharp notched plates by.

Dynamic substructure method for elastic fractal structures dynamic substructure method for elastic fractal structures leung, a. Initiation and propagation of cracks in rotating disks may cause catastrophic failures. Proceedings of the 5th international conference on vibration. Mathematics modeling of destruction under cyclic thermal. Finally, in our present work, the finite element methodfem is used to simulate the propagation of electromagnetic field in the structure of multicrystalline silicon. The fractallike finite element method ffem is developed to compute stress intensity factors sifs for isotropic homogeneous and bimaterial vnotched plates. An extended finite element method scheme for sharp vnotches is developed. Descriptionfem cuts a structure into several elements pieces of the structure.

Request pdf applications of numerical eigenfunctions in the fractal. In the ffem, the crackednotched body is divided into singular and regular regions. Thus the use of fractal geometry for scale invariant parameters emerged as a logical solution 68. In this paper, we extend our previous study to include the thermal effect for twodimensional isotropic thermal crack problems. The fractal like finite element method ffem is developed to compute stress intensity factors sifs for isotropic homogeneous and bimaterial vnotched plates. The fractal like finite element method ffem is one of the very few finite element methods which are able to calculate the sif directly. Therefore, determination of fracture parameters under different working conditions is an essential. Then reconnects elements at nodes as if nodes were pins or drops of glue that hold elements together.

Recently, it is the most convenient method for nonstationary temperature field calculations 4. However, little is known about how the detailed microstructure of part variation influences the assembly dimensional quality. Fractallike model of refractory structure, based on 3 fraction of grains. Comprehensive investigation of stress intensity factors in. Ample discussion of the computer implementation of the finite element. The required calculations of the collision rate between a gas. This makes the numerical evaluation of integrals of their inner products difficult and unstable. Roughness measurements on a variety of surfaces indicate that. The shear strength, an essential aspect of srm which governs the stability and the deformation, is rather necessary to be revealed properly. Boundary value problems are also called field problems. The field is the domain of interest and most often represents a physical structure. The fractal like finite element method ffem is employed to study the interaction of multiple cracks and to demonstrate the efficiency of the ffem for multiple crack problems. This process results in a set of simultaneous algebraic equations. The overall crack problem is divided into near field and far field regions as shown in fig.

Topology optimization approach method to find an optimal geometry size, shape, number of holes a mathematical approach using finite element analysis fea. Finite element method simulations of the nearfield. The super singular element method ssem is a semianalytical method, which combines the efficiency and accuracy of analytical solutions and the agility of standard finite element method. More information about the ffem can be found in previous work tsang et al.

We use the multilevelmultiscale dynamic substructure method so that we need only to eliminate a few nodes in advancing a fractal level. Fabrication of multscale fractallike structures by. The gray and blue areas represent soil and steel, respectively. This paper presents a singular edgebased smoothed finite element method esfem for solving twodimensional thermoelastic crack problems. The friction coefficient of fractal aggregates in the. The ssem is an improved version of the fractal like finite element method leung et al. Stabilized finite element method for the nonstationary navierstokes problem. The far field is modelled by the conventional finite element method. The obtained sif are reported in table 1 and compared to those obtained by tsang et al. Feb 01, 2011 dynamic substructure method for elastic fractal structures leung, a.

Leung and tsang 2000 presented an analysis of mode iii crack proble m by twolevel fem with finite number of layers. Download introduction to finite element method by j. Computation of the stress intensity factors of sharp. Two different classes of surfaces were modeled using fractals, representing dendritic and sponge like structures. Pdf we extend the twolevel finite element method 2lfem to the accurate. Request pdf twodimensional fractallike finite element method for thermoelastic crack analysis the fractallike finite element method has been proved to be very efficient and accurate in two. Determination of sharp vnotch stress intensity factors. Introduction to finite element analysis fea or finite. Multiphysics simulation and optimization for thermal. International journal for numerical methods in engineering 77. The fractallike finite element method ffem is developed to provide stress intensity factor sif values for bimaterial notches. The basic idea of ssem is to transform nodal displacements inside a superelement to global variables, which are the coefficients of the williams eigenfunction. The displacement fields around a bimaterial notch tip are derived and.

Relative performance of three meshreduction methods in. Computation of the stress intensity factors of sharp notched plates by the fractallike finite element. The model of crack appearance brittle material fatigue destruction in some element is based on strain concentration at elements parts, grains, for example. Analysis of beams and thin plates using the waveletgalerkin. International journal for numerical methods in engineering. Super singular element method ssem is an accurate method devoted to stress singularity analysis accomplished by stress analysts who have little or no experience of fracture mechanics. A systematic method to evaluate the shear properties of soil. Finite element simulation has been used as a virtual tool for tolerance. A novel modification of decouple scaled boundary finite.

In this paper, a new method based on the finite element method fem and fractal. Evaluation of mode iii stress intensity factors for bimaterial notched bodies using the fractallike finite element method, comput struct 20. Bimaterial vnotch stress intensity factors by the fractal. Mode i crack problems by fractal two level finite element methods. The fractal finite element method for addedmasstype problems. The result of fem usage is a matrix, containing geometric coordinates of some points inside object, time and temperature in these points. Moment distribution around polygonal holes in infinite plate, int j mech sci. Limit your results use the links below to filter your search results. The ffem presented allows general twodimensional, mixed mode, thermoelastic crack problems to be solved efficiently and accurately. Pdf twolevel finite element study of axisymmetric cracks. Click a category and then select a filter for your results. Jun 10, 2016 due to the special transportation and heat transfer characteristics, the fractal like yshape branching tube is used in valveless piezoelectric pumps as a nomovingpart valve.

It divides the cracked body into singular and regular regions. Determination of sharp vnotch stress intensity factors using. Galerkin method wgm and the wavelet finite element method wfem. The fractallike finite element method ffem is employed to study the interaction of multiple cracks and to demonstrate the efficiency of the ffem for multiple crack problems. Sep 01, 2016 this paper presents a singular edgebased smoothed finite element method esfem for solving twodimensional thermoelastic crack problems. Finite element based contact analysis of fractal surfaces core. Nov 16, 2016 effective, scalable method of lithographyless fabrication of such multiscale, ordered fractal like structures by controlling fluid interface instability in a heleshaw cell is presented here.

In this paper, a new method based on the finite element method fem and fractal geometry is proposed to explore the influence of the part variation microstructure on the assembly dimensional variation. Formulation of the fractallike finite element method ffem. The fractallike finite element method ffem has been proved to be an accurate and efficient method to analyse the stress singularity of crack tips. Variation analysis of nonrigid assembly using fem and fractals. Employing fractals and fem for detailed variation analysis of non. Determination of sharp vnotch stress intensity factors using the extended finite element method. The extraordinary issue of srm compared to finegrained soils is the grain size effect on the strength analysis. The finite element method aurelienlarcher,niyazicemde. Dynamic substructure method for elastic fractal structures. Computations of modes i and ii stress intensity factors of sharp. Hfractal seismic metamaterial with broadband lowfrequency. Twodimensional fractallike finite element method for.

Applications of numerical eigenfunctions in the fractal. Conventional finite elements are used to model both near field and far field regions. The finite element method fem, or finite element analysis fea, is a computational technique used to obtain approximate solutions of boundary value problems in engineering. The physical domain is first discretized using linear triangular elements which can be generated easily for complicated geometries, and then the smoothing domains are constructed based on edges of these elements.

Compactly supported wavelets and scaling functions have a finite number of derivatives which can be highly oscillatory. Proceedings of the 5th international conference on. Topology optimization for heat conduction using generative design algorithms consists of the design description, which is represented differently by the various algorithms implemented herein. The method allows the representation of notch faces independent of the mesh. Applications of the fractallike finite element method to. Another possible advantage of their use is the fact that the. All simulations were performed with a classical electrodynamics approach using the full set of maxwells equations that were solved with the threedimensional finite element method fem. Secondorder halfcell samples of varying material compositions were tested with densities spanning over two orders of magnitude from. The method does not require the use of any special singular element, and the sif is obtainable directly from some. Super singular element method for twodimensional crack. International journal of solids and structures, 44, 78627876 2007 article.

Reddy since the practice of the finite element method ultimately depends on ones ability to implement the technique on a digital computer, examples and exercises are designed to let the reader actually compute the solutions of various problems using computers. Kobayashiexperimental techniques in fracture mechanics. However, there have been little analyses on the flow resistance of the valveless piezoelectric pump, which is critical to the performance of the valveless piezoelectric pump with fractal like yshape branching tubes. The fractal like finite element method ffem has been proved to be an accurate and efficient method to analyse the stress singularity of crack tips.

Analysis of beams and thin plates using the waveletgalerkin method rodrigo bird burgos, marco antonio cetale santos, and raul rosas e silva 261. Computation of the stress intensity factors of sharp notched. Jul 18, 2017 twodimensional fractallike finite element method for thermoelastic crack analysis. The fractal finite element method ffem, originally developed for calculating. Due to the special transportation and heat transfer characteristics, the fractallike yshape branching tube is used in valveless piezoelectric pumps as a nomovingpart valve. Topology optimization for heat conduction using generative. Theory, implementation, and practice november 9, 2010 springer. Variation analysis of nonrigid assembly using fem and.

The fractal like finite element method ffem is developed to provide stress intensity factor sif values for bimaterial notches. Resilient 3d hierarchical architected metamaterials. The data that support the findings of this study are available from the corresponding author upon request. In the ffem, a body containing singular points such as cracknotch tips is divided. Request pdf employing fractals and fem for detailed variation analysis of non rigid. Finite element analysis was employed to validate the analytical estimates of the. Jan 24, 2017 the free energy is numerically minimized by a finite element method 36,37. The soilrock mixture srm is widely applied in the geotechnical engineering due to its better mechanical properties. The super singular element method ssem is a semianalytical method, which combines the efficiency and accuracy of analytical solutions and the agility of standard finiteelement method. The curve that delineates the two regions is denoted as.

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