Dynamic tensile process of blended fabric using finite element method

2020 ◽  
Vol 32 (5) ◽  
pp. 707-724
Author(s):  
Xuzhong Su ◽  
Xinjin Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Experimental Testing ◽  
Woven Fabrics ◽  
Weft Yarn ◽  
Tensile Fracture ◽  
Content Type ◽  
Tensile Process ◽  
Simulation Results ◽  
Element Method

PurposeTensile property is one basic mechanics performance of the fabric. In general, not only the tensile values of the fabric are needed, but also the dynamic changing process under the tension is also needed. However, the dynamic tensile process cannot be included in the common testing methods by using the instruments after fabric weaving.Design/methodology/approachBy choosing the weft yarn and warp yarn in the fabric as the minimum modeling unit, 1:1 finite element model of the whole woven fabrics was built by using AutoCAD software according to the measured geometric parameters of the fabrics and mechanical parameters of yarns. Then, the fabric dynamic tensile process was simulated by using the ANSYS software. The stress–strain curve along the warp direction and shrinkage rate curve along the weft direction of the fabrics were simulated. Meanwhile, simulation results were verified by comparing to the testing results.FindingsIt is shown that there are four stages during the fabric tensile fracture process along the warp direction under the tension. The first stage is fabric elastic deformation. The second stage is fabric yield deformation, and the change rate of stress begins to slow down. The third stage is fiber breaking, and the change of stress fluctuates since the breaking time of the fibers is different. The fourth stage is fabric breaking.Originality/valueIn this paper, the dynamic tensile process of blended woven fabrics was studied by using finite element method. Although there are differences between the simulation results and experimental testing results, the overall tendency of simulation results is the same as the experimental testing results.

Parallel finite-element method using domain decomposition and Parareal for transient motor starting analysis

2019 ◽  
Vol 38 (5) ◽  
pp. 1507-1520 ◽  
Author(s):  
Yasuhito Takahashi ◽  
Koji Fujiwara ◽  
Takeshi Iwashita ◽  
Hiroshi Nakashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parallel Computing ◽  
Domain Decomposition ◽  
Parallel Computation ◽  
Domain Decomposition Method ◽  
Space Time ◽  
Content Type ◽  
Parallel Performance ◽  
Element Method

Purpose This paper aims to propose a parallel-in-space-time finite-element method (FEM) for transient motor starting analyses. Although the domain decomposition method (DDM) is suitable for solving large-scale problems and the parallel-in-time (PinT) integration method such as Parareal and time domain parallel FEM (TDPFEM) is effective for problems with a large number of time steps, their parallel performances get saturated as the number of processes increases. To overcome the difficulty, the hybrid approach in which both the DDM and PinT integration methods are used is investigated in a highly parallel computing environment. Design/methodology/approach First, the parallel performances of the DDM, Parareal and TDPFEM were compared because the scalability of these methods in highly parallel computation has not been deeply discussed. Then, the combination of the DDM and Parareal was investigated as a parallel-in-space-time FEM. The effectiveness of the developed method was demonstrated in transient starting analyses of induction motors. Findings The combination of Parareal with the DDM can improve the parallel performance in the case where the parallel performance of the DDM, TDPFEM or Parareal is saturated in highly parallel computation. In the case where the number of unknowns is large and the number of available processes is limited, the use of DDM is the most effective from the standpoint of computational cost. Originality/value This paper newly develops the parallel-in-space-time FEM and demonstrates its effectiveness in nonlinear magnetoquasistatic field analyses of electric machines. This finding is significantly important because a new direction of parallel computing techniques and great potential for its further development are clarified.

Semi-analytical finite element method for simulating chemical dissolution-front instability problems in fluid-saturated porous media

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chongbin Zhao ◽  
B.E. Hobbs ◽  
Alison Ord
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Porous Media ◽  
Chemical Dissolution ◽  
Saturated Porous Media ◽  
Content Type ◽  
Front Instability ◽  
Fluid Saturated Porous Media ◽  
Dissolution Front ◽  
Element Method

PurposeThe objective of this paper is to develop a semi-analytical finite element method for solving chemical dissolution-front instability problems in fluid-saturated porous media.Design/methodology/approachThe porosity, horizontal and vertical components of the pore-fluid velocity and solute concentration are selected as four fundamental unknown variables for describing chemical dissolution-front instability problems in fluid-saturated porous media. To avoid the use of numerical integration, analytical solutions for the property matrices of a rectangular element are precisely derived in a purely mathematical manner. This means that the proposed finite element method is a kind of semi-analytical method. The column pivot element solver is used to solve the resulting finite element equations of the chemical dissolution-front instability problem.FindingsThe direct use of horizontal and vertical components of the pore-fluid velocity as fundamental unknown variables can improve the accuracy of the related numerical solution. The column pivot element solver is useful for solving the finite element equations of a chemical dissolution-front instability problem. The proposed semi-analytical finite element method can produce highly accurate numerical solutions for simulating chemical dissolution-front instability problems in fluid-saturated porous media.Originality/valueAnalytical solutions for the property matrices of a rectangular element are precisely derived for solving chemical dissolution-front instability problems in fluid-saturated porous media. The proposed semi-analytical finite element method provides a useful way for understanding the underlying dynamic mechanisms of the washing land method involved in the contaminated land remediation.

Prediction of Permeability Tensor for Plain Woven Fabric by Using Control Volume Finite Element Method

2003 ◽  
Vol 11 (6) ◽  
pp. 465-476 ◽  
Author(s):  
Y. S. Song ◽  
K. Chung ◽  
T. J. Kang ◽  
J. R. Youn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Control Volume ◽  
Three Dimensional ◽  
Woven Fabrics ◽  
Permeability Tensor ◽  
Woven Fabric ◽  
Stacking Order ◽  
Control Volume Finite Element ◽  
Element Method

The complete prediction of the second order permeability tensor for a three dimensional multi-axial preform is critical if we are to model and design the manufacturing process for composites by considering resin flow through a multi-axial fiber structure. In this study, the in-plane and transverse permeabilities for a woven fabric were predicted numerically by the coupled flow model, which combines microscopic and macroscopic flows. The microscopic and macroscopic flows were calculated by using 3-D CVFEM(control volume finite element method) for micro and macro unit cells. To avoid a checkerboard pressure field and improve the efficiency of numerical computation, a new interpolation function for velocity is proposed on the basis of analytical solutions. The permeability of a plain woven fabric was measured by means of an unidirectional flow experiment and compared with the permeability calculated numerically. Reverse and simple stacking of plain woven fabrics were taken into account and the relationship between the permeability and the structures of the preform such as the fiber volume fraction and stacking order is identified. Unlike other studies, the current study was based on a more realistic three dimensional unit cell. It was observed that in-plane flow is more dominant than transverse flow within the woven perform, and the effect of the stacking order of a multi-layered preform was negligible.

Diagram Design of Weaving Process for Touch-Feel Estimation of Plain-Woven Fabrics by Finite Element Method

2020 ◽  
Author(s):  
Hikaru Miyaki ◽  
Atsushi Sakuma
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Initial Stress ◽  
Woven Fabrics ◽  
Unit Cell ◽  
Open Set ◽  
Digital Evaluation ◽  
Adopted Model ◽  
Woven Structure ◽  
Element Method

Abstract Digital evaluation of touch-feel in textiles is useful to design fundamental functions of clothing. Here, it is necessary to design textiles for a detailed evaluation of the sensitivity in human’s feelings to consider the life-style creation in various aspects. Then, the objective of this paper is to propose a design method for plain-woven fabrics by touch-feel estimation considering the weaving process with the constitutive relations of yarn. Here, a diagram for control weaving is defined by the diameter of the yarn and displacement quantity of the weaving and the cramping by defining the theoretical thickness. For the effective design to consider various processes, unit-cell of plain-woven structures are fundamentally classified as open set models and closed set models. One of the unit-cell models in the finite element method (FEM) for the plain-woven structure is adopted because the adopted model can consider initial-stress distribution in the weaving process. For touch-feel estimation, an analysis model is constructed by warp, weft, and plungers that cramps the woven structure. A series of diagrams to compress with plungers is shown after constructing a plain-woven structure. As for analyzing the weaving process and the touch-feel estimation in one model, realization of the effective engineering is enabled. This procedure yields that the relationship between the displacement and simulation time suggests for consideration of initial-stress.

Stress, strain and displacement analysis of geodetic and conventional fuselage structure for future passenger aircraft

2019 ◽  
Vol 91 (6) ◽  
pp. 814-819
Author(s):  
Zdobyslaw Jan Goraj ◽  
Mariusz Kowalski ◽  
Bartlomiej Goliszek
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Weight Reduction ◽  
Composite Structures ◽  
Lattice Structure ◽  
Small Displacement ◽  
Structure Stability ◽  
Outer Diameter ◽  
Content Type ◽  
Element Method

Purpose This paper aims to present the results of calculations that checked how the longerons and frames arrangement affects the stiffness of a conventional structure. The paper focuses only on first stage of research – analysis of small displacement. Main goal was to compare different structures under static loads. These results are also compared with the results obtained for a geodetic structure fuselage model of the same dimensions subjected to the same internal and external loads. Design/methodology/approach The finite element method analysis was carried out for a section of the fuselage with a diameter of 6.3 m and a length equal to 10 m. A conventional and lattice structure – known as geodetic – was used. Findings Finite element analyses of the fuselage model with conventional and geodetic structures showed that with comparable stiffness, the weight of the geodetic fuselage is almost 20 per cent lower than that of the conventional one. Research limitations/implications This analysis is limited to small displacements, as the linear version of finite element method was used. Research and articles planned for the future will focus on nonlinear finite element method (FEM) analysis such as buckling, structure stability and limit cycles. Practical implications The increasing maturity of composite structures manufacturing technology offers great opportunities for aircraft designers. The use of carbon fibers with advanced resin systems and application of the geodetic fuselage concept gives the opportunity to obtain advanced structures with excellent mechanical properties and low weight. Originality/value This paper presents very efficient method of assessing and comparison of the stiffness and weight of geodetic and conventional fuselage structure. Geodetic fuselage design in combination with advanced composite materials yields an additional fuselage weight reduction of approximately 10 per cent. The additional weight reduction is achieved by reducing the number of rivets needed for joining the elements. A fuselage with a geodetic structure compared to the classic fuselage with the same outer diameter has a larger inner diameter, which gives a larger usable space in the cabin. The approach applied in this paper consisting in analyzing of main parameters of geodetic structure (hoop ribs, helical ribs and angle between the helical ribs) on fuselage stiffness and weight is original.

A MSFEM to simulate the eddy current problem in laminated iron cores in 3D

2019 ◽  
Vol 38 (5) ◽  
pp. 1667-1682 ◽  
Author(s):  
Karl Hollaus
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Eddy Current ◽  
Eddy Currents ◽  
Three Dimensional ◽  
Harmonic Balance Method ◽  
Three Dimensions ◽  
Magnetic Vector Potential ◽  
Content Type ◽  
Element Method

Purpose The simulation of eddy currents in laminated iron cores by the finite element method (FEM) is of great interest in the design of electrical devices. Modeling each laminate by finite elements leads to extremely large nonlinear systems of equations impossible to solve with present computer resources reasonably. The purpose of this study is to show that the multiscale finite element method (MSFEM) overcomes this difficulty. Design/methodology/approach A new MSFEM approach for eddy currents of laminated nonlinear iron cores in three dimensions based on the magnetic vector potential is presented. How to construct the MSFEM approach in principal is shown. The MSFEM with the Biot–Savart field in the frequency domain, a higher-order approach, the time stepping method and with the harmonic balance method are introduced and studied. Findings Various simulations demonstrate the feasibility, efficiency and versatility of the new MSFEM. Originality/value The novel MSFEM solves true three-dimensional eddy current problems in laminated iron cores taking into account of the edge effect.

A study of azimuthal electromagnetic wave LWD based on self-adaptive hp finite element method

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840073
Author(s):  
Hui Li ◽  
Yi-Bo Jiang ◽  
Jian-Wen Cai
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Electromagnetic Wave ◽  
Real Time ◽  
Simulation Results ◽  
Peak Value ◽  
Element Method ◽  
Self Adaptive ◽  
Hp Finite Element

Azimuthal electromagnetic wave logging-while-drilling (LWD) technology can detect weak electromagnetic wave signal and realize real-time resistivity imaging. It has great values to reduce drilling cost and increase drilling rate. In this paper, self-adaptive hp finite element method (FEM) has been used to study the azimuthal resistivity LWD responses in different conditions. Numerical simulation results show that amplitude attenuation and phase shift of directional electromagnetic wave signals are closely related to induced magnetic field and azimuthal angle. The peak value and polarity of geological guidance signals can be used to distinguish reservoir interface and achieve real-time geosteering drilling. Numerical simulation results also show the accuracy of the self-adaptive hp FEM and provide physical interpretation of peak value and polarity of the geological guidance signals.

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 New CZM for Interfacial Crack Growth

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Huifen Peng ◽  
Yujie Song ◽  
Ye Xia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Growth ◽  
Interface Crack ◽  
Interfacial Crack ◽  
Structure Design ◽  
Zone Model ◽  
Simulation Results ◽  
The Impact ◽  
Element Method

The cohesive zone model (CZM) has been widely used for numerical simulations of interface crack growth. However, geometrical and material discontinuities decrease the accuracy and efficiency of the CZM when based on the conventional finite element method (CFEM). In order to promote the development of numerical simulation of interfacial crack growth, a new CZM, based on the wavelet finite element method (WFEM), is presented. Some fundamental issues regarding CZM of interface crack growth of double cantilever beam (DCB) testing were studied. The simulation results were compared with the experimental and simulation results of CFEM. It was found that the new CZM had higher accuracy and efficiency in the simulation of interface crack growth. At last, the impact of crack initiation length and elastic constants of material on interface crack growth was studied based on the new CZM. These results provided a basis for reasonable structure design of composite material in engineering.

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