An equivalent model for sandwich panel with double-directional trapezoidal corrugated core

2019 ◽  
Vol 22 (7) ◽  
pp. 2445-2465
Author(s):  
Huimin Li ◽  
Lei Ge ◽  
Baosheng Liu ◽  
Haoran Su ◽  
Tianyi Feng ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Sandwich Panel ◽  
Equivalent Model ◽  
Geometrical Parameters ◽  
Detailed Model ◽  
Novel Structure ◽  
Homogeneous Method ◽  
Element Method

A novel sandwich panel with double-directional corrugated core is proposed in this paper. This complex-corrugated core makes the conventional detailed finite element analysis of large structures a tough work. Thus, an equivalent homogeneous method is proposed, the key of which is to obtain the equivalent property of this novel structure. The equivalent elastic modulus considering the effect of geometrical parameters is analytically derived and verified by finite element method. Besides, equivalent shear modulus and Poisson’s ratios are obtained by finite element method. Three-dimensional detailed and equivalent models are established for further validation of this equivalent homogeneous method. Results show that elastic modulus predicted by analytical formulas is in good agreement with that by finite element method no matter how geometrical parameters change. It has been proved that stretching deformation is dominating in thickness direction, and only corrugation along loading direction can bear the load. The proposed novel sandwich structure owns better mechanical property than the conventional one with single-corrugated core. The result by equivalent model agrees well with that by detailed model, which means that this equivalent homogeneous method can well predict the macroscopic property of this novel structure.

A numerical approach based on finite element method for the wrinkling analysis of dielectric elastomer membranes

2021 ◽  
pp. 1-37
Author(s):  
Guoyong Mao ◽  
Wei Hong ◽  
Martin Kaltenbrunner ◽  
Shaoxing Qu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thickness Distribution ◽  
Numerical Approach ◽  
Dielectric Elastomer ◽  
Equivalent Model ◽  
Maxwell Stress ◽  
Buckling Mode ◽  
Post Buckling ◽  
Element Method

Abstract Dielectric elastomer (DE) actuators are deformable capacitors capable of a muscle-like actuation when charged. When subjected to voltage, DE membranes coated with compliant electrodes may form wrinkles due to the Maxwell stress. Here, we develop a numerical approach based on the finite element method (FEM) to predict the morphology of wrinkled DE membranes mounted on a rigid frame. The approach includes two steps, I) pre-buckling and II) post-buckling. In step I, the first buckling mode of the DE membrane is investigated by substituting the Maxwell stress with thermal stress in the built-in function of the FEM platform SIMULIA Abaqus. In step II, we use this first buckling mode as an artificial geometric imperfection to conduct the post-buckling analysis. For this purpose, we develop an equivalent model to simulate the mechanical behavior of DEs. Based on our approach, the thickness distribution and the thinnest site of the wrinkled DE membranes subjected to voltage are investigated. The simulations reveal that the crests/troughs of the wrinkles are the thinnest sites around the center of the membrane and corroborate these findings experimentally. Finally, we successfully predict the wrinkles of DE membranes mounted on an isosceles right triangle frame with various sizes of wrinkles generated simultaneously. These results shed light on the fundamental understanding of wrinkled dielectric elastomers but may also trigger new applications such as programmable wrinkles for optical devices or their prevention in DE actuators.

scholarly journals Integrating the Finite Element Method with a Data-Driven Approach for Dam Displacement Prediction

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Chenfei Shao ◽  
Chongshi Gu ◽  
Zhenzhu Meng ◽  
Yating Hu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Random Coefficient ◽  
Arch Dam ◽  
Data Driven ◽  
The Finite Element Method ◽  
Random Coefficient Model ◽  
Proposed Model ◽  
Element Method

Both numerical simulations and data-driven methods have been applied in dam’s displacement modeling. For monitored displacement data-driven methods, the physical mechanism and structural correlations were rarely discussed. In order to take the spatial and temporal correlations among all monitoring points into account, we took the first step toward integrating the finite element method into a data-driven model. As the data-driven method, we selected the random coefficient model, which can make each explanatory variable coefficient of all monitoring points following one or several normal distributions. In this way, explanatory variables are constrained. Another contribution of the proposed model is that the actual elastic modulus at each monitoring point can be back-calculated. Moreover, with a Lagrange polynomial interpolation, we can obtain the distribution field of elastic modulus, rather than gaining one value for the whole dam in previous studies. The proposed model was validated by a case study of the concrete arch dam in Jinping-I hydropower station. It has a better prediction precision than the random coefficient model without the finite element method.

scholarly journals Combined Semianalytical and Numerical Static Plate Analysis. Part 2: Resultant Multipoint Boundary Problem

2018 ◽  
Vol 196 ◽  
pp. 01011
Author(s):  
Oleg Negrozov ◽  
Pavel Akimov ◽  
Marina Mozgaleva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Problem ◽  
Thin Plates ◽  
Geometrical Parameters ◽  
Element Mesh ◽  
Multipoint Boundary ◽  
Basic Dimension ◽  
Plate Analysis ◽  
Element Method

The distinctive paper is devoted to solution of multipoint boundary problem of plate analysis (Kirchhoff model) based on combined application of finite element method (FEM) and discrete-continual finite element method (DCFEM). As is known the Kirchhoff-Love theory of plates is a two-dimensional mathematical model that is normally used to determine the stresses and deformations in thin plates subjected to forces and moments. The given domain, occupied by considering structure, is embordered by extended one. The field of application of DCFEM comprises fragments of structure (subdomains) with regular (constant or piecewise constant) physical and geometrical parameters in some dimension (“basic” dimension). DCFEM presupposes finite element mesh approximation for non-basic dimension of extended domain while in the basic dimension problem remains continual. FEM is used for approximation of all other subdomains (it is convenient to solve plate bending problems in terms of displacements). Coupled multilevel approximation model for extended domain and resultant multipoint boundary problem are constructed. Brief information about software systems and verification samples are presented as well.

An Equivalent Constitutive Model of Cancellous Bone With Fracture Prediction

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Mohammad Salem ◽  
Lindsey Westover ◽  
Samer Adeeb ◽  
Kajsa Duke
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cast Iron ◽  
Constitutive Model ◽  
Cancellous Bone ◽  
Equivalent Model ◽  
Plasticity Model ◽  
Microscale Model ◽  
Computational Resources ◽  
Element Method

Abstract To simulate the mechanical and fracture behaviors of cancellous bone in three anatomical directions and to develop an equivalent constitutive model. Microscale extended finite element method (XFEM) models of a cancellous specimen were developed with mechanical behaviors in three anatomical directions. An appropriate abaqus macroscale model replicated the behavior observed in the microscale models. The parameters were defined based on the intermediate bone material properties in the anatomical directions and assigned to an equivalent nonporous specimen of the same size. The equivalent model capability was analyzed by comparing the micro- and macromodels. The hysteresis graphs of the microscale model show that the modulus is the same in loading and unloading; similar to the metal plasticity models. The strength and failure strains in each anatomical direction are higher in compression than in tension. The microscale models exhibited an orthotropic behavior. Appropriate parameters of the cast iron plasticity model were chosen to generate macroscale models that are capable of replicating the observed microscale behavior of cancellous bone. Cancellous bone is an orthotropic material that can be simulated using a cast iron plasticity model. This model is capable of replicating the microscale behavior in finite element (FE) analysis simulations without the need for individual trabecula, leading to a reduction in computational resources without sacrificing model accuracy. Also, XFEM of cancellous bone compared to traditional finite element method proves to be a valuable tool to predict and model the fractures in the bone specimen.

FEM Analysis on Thermal Stress of Desulphurization Injection Lance

2007 ◽  
Vol 336-338 ◽  
pp. 1531-1533
Author(s):  
Jian Qiang Qi ◽  
Yong Huang ◽  
Shi Xi Ouyang ◽  
Nan Li ◽  
Jiang Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Elastic Modulus ◽  
Fem Analysis ◽  
Finite Element Method Model ◽  
Method Model ◽  
Element Method

By means of a finite element method model, the effects of property parameters of refractory on thermal stress of injection lance have been studied. The results show that the maximum thermal stress increases with the improvement of thermal conductivity and elastic modulus of refractory, while it decreases at first and then increases with the improvement of the coefficient of expansion of refractory.

scholarly journals Application of Finite Element Method for Analysis of Nanostructures

2017 ◽  
Vol 11 (2) ◽  
pp. 116-120 ◽  
Author(s):  
Jozef Bocko ◽  
Pavol Lengvarský
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Beam Elements ◽  
Stiffness Properties ◽  
Force Displacement ◽  
The Finite Element Model ◽  
Element Method

AbstractThe paper deals with application of the finite element method in modelling and simulation of nanostructures. The finite element model is based on beam elements with stiffness properties gained from the quantum mechanics and nonlinear spring elements with force-displacement relation are gained from Morse potential. Several basic mechanical properties of structures are computed by homogenization of nanostructure, e.g. Young's modulus, Poisson's ratio. The problems connecting with geometrical parameters of nanostructures are considered and their influences to resulting homogenized quantities are mentioned.

scholarly journals CALCULATION OF CONTROLLED TIGHTENING EFFORT IN GROUP BOLTED JOINT

2020 ◽  
Vol 2020 (6) ◽  
pp. 12-21
Author(s):  
Ruslan Guchinskiy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reliable Estimate ◽  
Load Factor ◽  
Geometrical Parameters ◽  
Standard Group ◽  
Bolted Joint ◽  
Operation Conditions ◽  
First Time ◽  
Element Method

The optimum value choice of a tightening effort is significant for assurance of a reliable operation of a group bolted joint. A work goal consists in the calculation and comparison of essential conditions of tightening efforts for a bolted joint of a bracket and a plate with analytical and numerical methods. For the first time it is obtained that the use of tightening factors recommended in literature by the condition of joint density may fail to ensure its non-disclosure. It is shown that a basic load factor for a bolt of a group joint depends not only upon bolt and flanges yielding, but upon loading and geometrical parameters of a joint. Basic loading factors obtained through a finite element method for a group bolted joint proved to be below ones defined analytically. The use of the procedure for bolt calculations on the basis of the assurance of joint complete non-disclosure results in increased values of tightening efforts caused by non-uniformity of contact stress distribution in flanges because of tightening. There is specified a field of application of the calculation procedure on joint non-disclosure – group joints with high stiffness flanges. At preliminary estimate the efforts for tightening a standard group joint a procedure of joint non-disclosure with the increased tightening factor and a condition of shift absence is recommended for use. To obtain a reliable estimate of the required tightening effort after its preliminary selection it is recommended to check up operation conditions of a group bolted joint with the aid of the calculation through the finite element method.

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