Study on the relationship between pressure and stiffness coefficient, and elastic elongation of the top part of men’s socks using finite element method

2015 ◽  
Vol 27 (5) ◽  
pp. 751-766 ◽  
Author(s):  
Rui Dan ◽  
Xuerong Fan ◽  
Zhen Shi ◽  
Mei Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Human Body ◽  
Research Work ◽  
Lower Leg ◽  
Elastic Contact ◽  
Stiffness Coefficient ◽  
Content Type ◽  
The Relationship

Purpose – The purpose of this paper is to study a new method to appraise pressure comfort through displacement distribution, and then explore the relationship between pressure and stiffness coefficient, and elastic elongation of the top part of men’s socks using finite element method. Design/methodology/approach – Through 3D body scanning, a biomechanical lower leg cross-section model is constructed for simulating elastic contact between human body and top part of socks. The human body is regarded as an elastomer and the contact between lower leg and top part of socks is elastic contact, displacement distribution tendency under pressure can be obtained using ANSYS, and the elastic elongation of top part of socks after putting on was calculated based on the displacement values. In this research work, the authors discuss in details with the relationship between pressure and stiffness coefficient, and elastic elongation of top part of socks. Findings – In this research work, the mathematical equation of pressure is obtained which describe the relationship between pressure and stiffness coefficient, and elastic elongation of top part of socks. The results indicated that the predictive values of pressure show good agreement with measured ones after χ2 test. All these solutions supply a theory basis for forecasting of the clothing pressure. Research limitations/implications – This paper is unconcerned with the simulating of pressure distribution and variation trend when dressing during the course of walking and running. Originality/value – The paper provides a finite element simulation model of lower leg cross-section located at the top part of men’s socks, and study the relationship between pressure and stiffness coefficient, and elastic elongation of top part of socks. It can supply a new method to appraise pressure comfort.

Finite element simulation on the relationship between pressure and displacement for the waist of elastic pantyhose

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rui Dan ◽  
Zhen Shi
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Research Work ◽  
Lumbar Vertebrae ◽  
Objective Evaluation ◽  
Quadratic Equation ◽  
New Method ◽  
Content Type ◽  
Displacement Distribution ◽  
The Relationship

PurposeObjective appraisal of pressure comfort is the key point of optimal designing of clothing. The purpose of this paper is to study a new method to provide pressure comfort for the waist of elastic pantyhose through the relationship between pressure and displacement using the finite element method (FEM).Design/methodology/approachThis paper presented a simulation model of the waist cross section consisting of three parts, namely skin, soft tissue and lumbar vertebrae, respectively, according to CT scan. The finite element the model of waist cross-section was established using Mimics software. The pressure–displacement quadratic equation can be obtained using ANSYS software and fitting curves. Meanwhile, we divide the waist cross-section into 12 equal regions according to angle, and then the area shrinkage mass of the waist cross-section can be calculated, respectively.FindingsIn this research work, we got the displacement distribution trend of elastic pantyhose at the waist cross section according to the area shrinkage mass of 12 regions, and this displacement could be used as an objective evaluation index for pressure comfort. All these solutions supply a theoretical reference for optimal design of the women's elastic pantyhose.Originality/valueThe paper analyzed the relationship between pressure and displacement for the waist of elastic pantyhose using FEM, and then got the displacement distribution trend of elastic pantyhose at the waist cross section according to the area shrinkage mass of different regions. It can supply a new method to appraise pressure comfort.

Finite element simulation on clothing pressure and body deformation of the top part of men’s socks using curve fitting equations

2015 ◽  
Vol 27 (2) ◽  
pp. 207-220 ◽  
Author(s):  
Mei Zhang ◽  
Henan Dong ◽  
Xuerong Fan ◽  
Rui Dan
Keyword(s):  
Functional Equation ◽  
Finite Element ◽  
Contact Pressure ◽  
Cross Section ◽  
Curve Fitting ◽  
Lower Leg ◽  
Quadratic Functional ◽  
Content Type ◽  
The Relationship ◽  
Variation Tendency

Purpose – Objective appraisal of pressure comfort is the basement of optimal design of clothing. The purpose of this paper is to study a new method to appraise pressure comfort through displacement distribution, and then explored the multiple relationship between pressure and displacement on the lower leg cross-section using finite element method (FEM) and curve fitting. Design/methodology/approach – This paper presented a 2D simulation model of the lower leg cross-section consisting of three layer different mechanical properties, namely skin, soft tissue, and bone. Analyzed the relationship and variation tendency between contact pressure and strain, calculated the multiple relationship between pressure and displacement on the lower leg cross-section where located at the top part of men’s socks in detail, and then obtained the quadratic functional equation between angle and pressure/displacement ratio through segmented curve fitting using Origin 7.5 software. Findings – In this research work, the mathematical equation is obtained which describe the relationship between angle and pressure/displacement of the top part of men’s socks. On the premise of the known contact pressure values on the lower leg cross-section, the corresponding displacement values on the human body surface can be obtained by the functional equation under stress, and this displacement could be used as an objective evaluation index for pressure comfort. Based on these conclusions, the authors could provide theoretical reference for pressure prediction and optimizing the design of clothing. Research limitations/implications – This paper is unconcerned with the simulating of pressure, strain, and displacement distribution when dressing during the course of walking and running. Originality/value – The paper analyzed the relationship and variation tendency between contact pressure and strain using FEM, and then obtained the quadratic functional equation between angle and pressure/displacement ratio of the top part of socks. It can supply a new method to appraise pressure comfort.

Fatigue damage in bending of reinforced concrete frames using non-destructive tests for dynamic strength of the cylinder

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dragan D. Milašinović ◽  
Aleksandar Landović ◽  
Danica Goleš
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Damage ◽  
Cross Section ◽  
Modal Parameters ◽  
The Finite Element Method ◽  
Concrete Frames ◽  
Content Type ◽  
Non Destructive

PurposeThe purpose of this paper is to contribute to the solution of the fatigue damage problem of reinforced concrete frames in bending.Design/methodology/approachThe problem of fatigue damage is formulated based on the rheological–dynamical analogy, including a scalar damage variable to address the reduction of stiffness in strain softening. The modal analysis is used by the finite element method for the determination of modal parameters and resonance stability of the selected frame cross-section. The objectivity of the presented method is verified by numerical examples, predicting the ductility in bending of the frame whose basic mechanical properties were obtained by non-destructive testing systems.FindingsThe modal analysis in the frame of the finite element method is suitable for the determination of modal parameters and resonance stability of the selected frame cross-section. It is recommended that the modulus of elasticity be determined by non-destructive methods, e.g. from the acoustic response.Originality/valueThe paper presents a novel method of solving the ductility in bending taking into account both the creep coefficient and the aging coefficient. The rheological-dynamical analogy (RDA) method uses the resonant method to find material properties. The characterization of the structural damping via the damping ratio is original and effective.

A finite element analysis of an elastic contact between a layered cylindrical hollow roller and flat contact

2017 ◽  
Vol 69 (1) ◽  
pp. 30-41 ◽  
Author(s):  
Mitul Thakorbhai Solanki ◽  
Dipak Vakharia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Research Work ◽  
Roller Bearing ◽  
Von Mises Stress ◽  
Elastic Contact ◽  
Element Analysis ◽  
Content Type ◽  
Contact Width ◽  
Flat Contact

Purpose The purpose of this paper is to present a finite element analysis (FEA) which shows the comparison between a layered cylindrical hollow roller bearing and hollow roller bearing. Design/methodology/approach In this work, FEA is carried out to solve the elastic contact between a layered cylindrical hollow roller and flat contact for different hollowness percentages ranging from 10 to 80 per cent. Graphical solution is developed to determine the optimum hollowness of a cylindrical roller bearing for which induced bending stress should be within endurance limit of the material. Findings Different parameters such as von Mises stress, contact pressure, contact width and deformation are shown here. Originality/value The value of this research work is the calculation of contact width and other parameters using FEA for layered cylindrical hollow roller bearing.

Homogenization of multi-turn coil with elliptic cross-section using complex permeability

2019 ◽  
Vol 38 (3) ◽  
pp. 999-1008 ◽  
Author(s):  
Shogo Fujita ◽  
Hajime Igarashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Elements ◽  
Cross Section ◽  
Fe Analysis ◽  
Complex Permeability ◽  
Elliptic Cross Section ◽  
Content Type ◽  
Elliptic Cross ◽  
Good Agreement

Purpose The tensor complex permeability of a multi-turn coil with elliptic cross-section is analytically expressed. In field analysis, a multi-turn coil can be modeled by the uniform material that has the present tensor complex permeability. It is shown that the frequency characteristic of the present tensor complex permeability is in good agreement with that evaluated by finite element method applied to a unit cell of the multi-turn coil region. Design/methodology/approach The authors introduce a new method to evaluate the complex permeability of a multi-turn rectangular coil. To obtain the complex permeability of a rectangular coil in a closed form, it is approximated as an elliptic coil. Because the rectangular coil has different complex permeabilities in the vertical and horizontal directions, the complex permeability have to be defined in a tensor form. It suffices to discretize the coil region into rather coarse finite elements without considering the skin depth in contrast to the conventional finite element method. Findings The proposed method is shown to give the impedance of multi-turn coils which is in good agreement with results obtained by the conventional finite element (FE) analysis. By extending the proposed approach, the authors can easily perform 3D FE analysis without difficulty in discretization of the coil region with fairly fine finite elements. Moreover, they found that the approximation of rectangular coils as the elliptic coils is valid for analysis of quasi-static fields using this homogenization method. Originality/value The novelty of this study is in the approximation of the rectangular coils with elliptic coils, and the complex permeability for them is formulated here in a closed form. The proposed formula includes that for the round coils. Using the present method, the authors analyze the rectangular coils without fine discretization.

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.

scholarly journals Assessment of Rectangular Cavity in Concrete Gravity Retaining Wall using Finite Element Method

2019 ◽  
Vol 8 (4) ◽  
pp. 2656-2661
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Cross Section ◽  
Retaining Wall ◽  
Rectangular Cavity ◽  
Gravity Retaining Wall ◽  
The Cross ◽  
Conditions Of Stability ◽  
Element Method

The design of the Gravity retaining wall (GRW) is a trial and error process. Prevailing conditions of backfill are used to determine the profile of GRW, which proceeds with the selection of provisional dimensions. The optimum section is having factors of safety of stability higher than the allowable values and stresses in the cross-section smaller than permissible. The cross-section is designed to fulfill conditions of stability, subjected to very low stresses. The strength of the material, which is provided in the cross-section remains unutilized. A computer program is developed to find stresses at various locations on the cross-section of GRW using the Finite Element Method (FEM). A discontinuity in the form of a rectangular cavity is introduced in the cross-section of GRW to optimize it. The rectangular cavity is introduced in the cross-section of GRW at different locations. An attempt is made in this paper to find the stress distribution in the gravity retaining wall cross-section and to study the effect of the rectangular cavity on the stress distribution. Two cases representing different locations are considered to study the effect of the cavity. The location of the cavity is distinguished by the parameter w, the effects of cases with varied was 0.2305 (Case-I) and 0.1385 (Case-II) are observed. The cavity, which is provided not only makes the wall structurally efficient but also economically feasible.

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