scholarly journals Finite Element Analysis of Mixing Flow in a Circular Vessel with Concentric Three Blade Agitator

2021 ◽  
Vol 10 (2) ◽  
pp. 1056-1064
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Research Work ◽  
Time Derivative ◽  
Galerkin Approximation ◽  
Isothermal Condition ◽  
Polar Coordinates ◽  
Mixing Process ◽  
Navier Stokes Equation ◽  
Numerical Predictions

This study is to investigate the optimisation of the mixing process in two folds, such as, homogenisation of material and to predict the power consumption. This research work is extension of other studies conducted by different researchers. In all other research investigations, no one had employed agitator. The geometry features a cylindrical vessel fixed with a mechanically revolving stirrer along with fixed agitator. The flow is modelled for incompressible constant viscosity Newtonian fluid with isothermal condition. Simulated numerical predictions are achieved through so called a finite element algorithm. The governing equations considered here are two–dimensional equation continuity and time–dependent Navier–Stokes equation in cylindrical polar coordinates. Employed numerical scheme is constructed in multiple–stages. Where, time derivative is discretised in two step quadratic approximation of Taylor series expansion. Whereas, Galerkin approximation is employed for spatial discretisation. Whilst, at second step pressure correction is adopted through projection method. Whilst, implicitness is applied on only diffusion term to make algorithm in semi– implicit form of TGPC. The influences of inertia will be analysed through fluid inertia using dimensionless Reynolds number. The effects of rotational speed of stirrer with agitator will be explored. The computed results will be illustrated for pressure by isobars and flow structure through streamline contours plots. The keyaim of the numerical study is to estimate the improved possible design of the blenders, that enhance the mixing process

Prediction of Microelectronic Substrate Warpage Using Homogenized Thermomechanical Finite Element Models

2005 ◽  
Author(s):  
Parsaoran Hutapea ◽  
Joachim L. Grenestedt ◽  
Mitul Modi ◽  
Michael Mello ◽  
Kristopher Frutschy
Keyword(s):  
Finite Element ◽  
Effective Properties ◽  
Isothermal Condition ◽  
Numerical Approach ◽  
Thermomechanical Properties ◽  
Temperature Changes ◽  
Numerical Predictions ◽  
Homogenization Approach ◽  
Simple Bounds ◽  
Complex Features

High-density microelectronic substrates, used in organic CPU packages, are comprised of several polymer, fiber-weave, and copper layers and are filled with a variety of complex features such as traces, micro-vias, Plated-Through-Holes (PTH), and adhesion holes. When subjected to temperature changes, these substrates may warp, driven by the mismatch in Coefficients of Thermal Expansion (CTE) of the constituent materials. This study focused on predicting substrate warpage in an isothermal condition. The numerical approach consisted of three major steps: estimating homogenized (effective) thermomechanical properties of the features; calculating effective properties of discretized layers using the effective properties of the features; and assembling the layers to create 2D Finite Element (FE) plate models and to calculate warpage of the whole substrates. The effective properties of the features were extracted from 3D unit cell FE models, and closed-form approximate expressions were developed using the numerical results, curve fitting, and some simple bounds. The numerical approach was applied to predict warpage of production substrates, analyzed, and validated against experimentally measured stiffness and CTEs. In this paper, the homogenization approach, numerical predictions, and experimental validation are discussed.

Numerical Simulation of Rotational Behavior of Bolted Glulam Beam-to-Column Connections with Slotted-In Steel Plates

2016 ◽  
Vol 858 ◽  
pp. 22-28 ◽  
Author(s):  
Ming Qian Wang ◽  
Xiao Bin Song ◽  
Xiang Lin Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Evolution ◽  
Numerical Study ◽  
Material Model ◽  
Element Model ◽  
Rotational Behavior ◽  
Failure Behavior ◽  
Glulam Beam ◽  
Numerical Predictions

This paper presents the results of a numerical study on rotational behavior of bolted glulam beam-to-column connections. Since wood often exhibited complex failure behavior under different loading states, a three dimensional anisotropic damage analysis model of wood was initially developed based on continuum damage mechanics theory for progressive failure analysis of wood. The damage model basically consisted of two ingredients: the failure criterion proposed by Sandhaas was chosen to capture the damage onset; three independent damage variables were adopted to control the ductile and brittle damage evolution process of wood. This material model was implemented in a commercial available finite element method based code using a user-material subroutine. Finite element model of bolted connection coupled with the proposed material model was established to further investigate the failure modes and moment resistance of such connections. It was found that the damage evolution progress was very similar to the crack development from experimental tests. By comparing the experimental results and numerical predictions, a fair agreement of the initial stiffness and moment resistance was found with modeling error less than 3%, which implied that the finite element model was suitable to simulate the rotational behavior of such connections. This research could provide the reference for the design of bolted glulam connections in heavy timber structures.

Finite Element Modeling of Resurfacing Hip Prosthesis: Estimation of Accuracy Through Experimental Validation

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Fulvia Taddei ◽  
Saulo Martelli ◽  
Harinderjit Singh Gill ◽  
Luca Cristofolini ◽  
Marco Viceconti
Keyword(s):  
Finite Element ◽  
Femoral Neck ◽  
Finite Element Modeling ◽  
Hip Joint ◽  
Numerical Study ◽  
Biomechanical Analysis ◽  
Implantation Technique ◽  
Element Modeling ◽  
Numerical Predictions ◽  
Satisfactory Outcome

Metal-on-metal hip resurfacing is becoming increasingly popular, and a number of new devices have been recently introduced that, in the short term, appear to have satisfactory outcome but many questions are still open on the biomechanics of the resurfaced femur. This could be investigated by means of finite element analysis, but, in order to be effective in discerning potential critical conditions, the accuracy of the models’ predictions should be assessed. The major goal of this study was to validate, through a combined experimental-numerical study, a finite element modeling procedure for the simulation of resurfaced femurs. In addition, a preliminary biomechanical analysis of the changes induced in the femoral neck biomechanics by the presence of the device was performed, under a physiologic range of hip joint reaction directions. For this purpose, in vitro tests and a finite element model based on the same specimen were developed using a cadaver femur. The study focused on the Conserve Plus, one of the most common contemporary resurfacing designs. Five loading configurations were identified to correspond to the extremes of physiological directions for the hip joint. The agreement between experimental measurements and numerical predictions was good both in the prediction of the femoral strains (R2>0.9), and in the prosthesis micromotions (error<20 μm), giving confidence in the model predictions. The preliminary biomechanical analysis indicated that the strains in the femoral neck are moderately affected by the presence of the prosthesis, apart from localized strain increments that can be considerable, always predicted near the stem. Low micromotions and contact pressure were predicted, suggesting a good stability of the prosthesis. The model accuracy was good in the prediction of the femoral strains and moderately good in the prediction of the bone-prosthesis micromovements. Although the investigated loading conditions were not completely physiological, the preliminary biomechanical analysis showed relatively small changes for the proximal femur after implantation. This validated model can support realistic simulations to examine physiological load configurations and the effects of variations in prosthesis design and implantation technique.

scholarly journals Space Analyticity and Bounds for Derivatives of Solutions to the Evolutionary Equations of Diffusive Magnetohydrodynamics

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1789
Author(s):  
Vladislav Zheligovsky
Keyword(s):  
Stokes Equation ◽  
Arbitrary Order ◽  
Numerical Study ◽  
A Priori ◽  
Auxiliary Problem ◽  
Time Derivative ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Evolutionary Equations ◽  
Derivatives Of

In 1981, Foias, Guillopé and Temam proved a priori estimates for arbitrary-order space derivatives of solutions to the Navier–Stokes equation. Such bounds are instructive in the numerical investigation of intermittency that is often observed in simulations, e.g., numerical study of vorticity moments by Donzis et al. (2013) revealed depletion of nonlinearity that may be responsible for smoothness of solutions to the Navier–Stokes equation. We employ an original method to derive analogous estimates for space derivatives of three-dimensional space-periodic weak solutions to the evolutionary equations of diffusive magnetohydrodynamics. Construction relies on space analyticity of the solutions at almost all times. An auxiliary problem is introduced, and a Sobolev norm of its solutions bounds from below the size in C3 of the region of space analyticity of the solutions to the original problem. We recover the exponents obtained earlier for the hydrodynamic problem. Moreover, the same approach is followed here to derive and prove similar a priori bounds for arbitrary-order space derivatives of the first-order time derivative of the weak MHD solutions.

scholarly journals Numerical Investigations on Characteristics of Stresses in U-Shaped Metal Expansion Bellows

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
S. H. Gawande ◽  
N. D. Pagar ◽  
V. B. Wagh ◽  
A. A. Keste
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Research Work ◽  
Mechanical Device ◽  
Element Analysis ◽  
Radial And Axial Displacements ◽  
Metal Bellows ◽  
New Type ◽  
Different Characteristics ◽  
Good Agreement

Metal expansion bellows are a mechanical device for absorbing energy or displacement in structures. It is widely used to deal with vibrations, thermal expansion, and the angular, radial, and axial displacements of components. The main objective of this paper is to perform numerical analysis to find various characteristics of stresses in U-shaped metal expansion bellows as per the requirement of vendor and ASME standards. In this paper, extensive analytical and numerical study is carried out to calculate the different characteristics of stresses due to internal pressure varying from 1 MPa to 2 MPa in U-shaped bellows. Finite element analysis by using Ansys14 is performed to find the characteristics of U-shaped metal expansion bellows. Finally, the results of analytical analysis and finite element method (FEM) show a very good agreement. The results of this research work could be used as a basis for designing a new type of the metal bellows.

scholarly journals A Novel Finite Element Method Approach in the Modelling of Edge Trimming of CFRP Laminates

2021 ◽  
Vol 11 (11) ◽  
pp. 4743
Author(s):  
Fernando Cepero-Mejias ◽  
Nicolas Duboust ◽  
Vaibhav A. Phadnis ◽  
Kevin Kerrigan ◽  
Jose L. Curiel-Sosa
Keyword(s):  
Finite Element ◽  
Tool Wear ◽  
Cutting Tool ◽  
Machining Process ◽  
Machining Forces ◽  
General Terms ◽  
Numerical Predictions ◽  
Composite Damage ◽  
Edge Trimming ◽  
Optimal Cutting Parameters

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45∘ and 90∘ manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation.

scholarly journals A numerical study of a size-dependent finite-element based unit cell with primary and secondary voids

2021 ◽  
pp. 104493
Author(s):  
Vetle Espeseth ◽  
David Morin ◽  
Jonas Faleskog ◽  
Tore Børvik ◽  
Odd Sture Hopperstad
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Unit Cell ◽  
Size Dependent
Sign in / Sign up

Export Citation Format

Share Document