Investigation of Finite Element Thermal Models for Workpiece Temperature in Cylinder Boring

2015 ◽  
Author(s):  
Lei Chen ◽  
Juhchin A. Yang ◽  
Albert J. Shih ◽  
Bruce L. Tai
Keyword(s):  
Finite Element ◽  
Heat Carrier ◽  
Computational Efficiency ◽  
Surface Heat ◽  
Computational Time ◽  
Depth Of Cut ◽  
Thermal Models ◽  
Workpiece Temperature ◽  
Fine Mesh ◽  
Computational Resources

The accuracy and computational efficiency of four finite element thermal models for workpiece temperature in cylinder boring are studied. High temperature in precision cylinder boring of automotive engine block can distort the workpiece, leading to thermally-induced dimensional and geometrical errors. In cylinder boring, the depth of cut is small compared to the bore diameter, so a fine mesh is usually needed to analyze the workpiece temperature distribution; however fine mesh on a relatively large workpiece also takes extensive computational resources. To understand the trade-off between accuracy and computational efficiency, the advection, surface heat, heat carrier, and ring heat finite element thermal models are introduced and compared quantitatively in a boring process. It is found comparable global temperature estimation from all four models. For the temperature near the cutting zone, the advection and surface heat models are more accurate to predict local temperatures but consume more computational resources. The heat carrier model predicts the surface temperature with reasonable accuracy and computational time. The ring heat model is the most computationally efficient but fails to accurately estimate local peak temperatures.

Optimization of Finite Element Modeling Methodology for Projectile Models

2006 ◽  
Author(s):  
Srujanbabu Sridharala ◽  
Mohamed B. Trabia ◽  
Brendan O'Toole ◽  
Vinod Chakka ◽  
Mostafiz Chowdhury
Keyword(s):  
Finite Element ◽  
Expert System ◽  
Finite Element Modeling ◽  
Computational Time ◽  
Element Modeling ◽  
Fine Mesh ◽  
Aspect Ratios ◽  
Time Accuracy ◽  
Optimization Search ◽  
Launch Event

Gun-fired projectiles are subjected to severe loads over extremely short duration. There is a need to better understand the effects of these loads on components within a projectile. While experimental data can be helpful in understanding projectile launch phenomena, collecting such data is usually difficult. There are also limitations on the reliability of sensors under these circumstances. Finite element modeling (FEM) can be used to model the projectile launch event. Currently, engineers usually use large number of elements to accurately model the projectile launch event, which results in an extremely long computational time. FEM results in these cases are always subject to questions regarding accuracy of the results and proof of mesh stability This paper presents an expert system that can reduce computational time needed to perform FEM of gun-fired projectiles. The proposed approach can result in reducing computational time while ensuring that accuracy of results is not affected. Recommendations of the expert system are reached through two stages. In the first stage, an equivalent projectile with simple geometry is created to reduce the complexity of the model. In the second stage, parameters controlling mesh density of the equivalent projectile are used as variables in an optimization scheme with the objective of reducing computational time. Accuracy of the acceleration results from an optimized model with respect to a model with an extremely fine mesh is used as an inequality constraint within the optimization search. A projectile model meshed with aspect ratios obtained from the optimization search produces good agreement with the finite element results of the original densely-meshed projectile model while significantly reducing computational time. It is anticipated that this approach can make it easier to conduct parametric analysis or optimization studies for projectile design.

Improving finite element results in modeling heart valve mechanics

2018 ◽  
Vol 232 (7) ◽  
pp. 718-725 ◽  
Author(s):  
Emily Earl ◽  
Hadi Mohammadi
Keyword(s):  
Finite Element ◽  
Heart Valve ◽  
Numerical Technique ◽  
Strain Tensor ◽  
Computational Cost ◽  
Constitutive Models ◽  
Least Square ◽  
Computational Time ◽  
Finite Element Models ◽  
Fine Mesh

Finite element analysis is a well-established computational tool which can be used for the analysis of soft tissue mechanics. Due to the structural complexity of the leaflet tissue of the heart valve, the currently available finite element models do not adequately represent the leaflet tissue. A method of addressing this issue is to implement computationally expensive finite element models, characterized by precise constitutive models including high-order and high-density mesh techniques. In this study, we introduce a novel numerical technique that enhances the results obtained from coarse mesh finite element models to provide accuracy comparable to that of fine mesh finite element models while maintaining a relatively low computational cost. Introduced in this study is a method by which the computational expense required to solve linear and nonlinear constitutive models, commonly used in heart valve mechanics simulations, is reduced while continuing to account for large and infinitesimal deformations. This continuum model is developed based on the least square algorithm procedure coupled with the finite difference method adhering to the assumption that the components of the strain tensor are available at all nodes of the finite element mesh model. The suggested numerical technique is easy to implement, practically efficient, and requires less computational time compared to currently available commercial finite element packages such as ANSYS and/or ABAQUS.

A Modified Strain-displacement Method for High Accuracy 8-Node Solid Finite Element

2020 ◽  
Author(s):  
Sacharuck Pornpeerakeat ◽  
Krissachai Sriboonma ◽  
Arisara Chaikittiratana
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Higher Order ◽  
Curvilinear Coordinates ◽  
Computational Time ◽  
Element Formulation ◽  
Displacement Method ◽  
Energy Equivalence ◽  
Computational Resources ◽  
Locking Phenomena

Higher-order three-dimensional solid elements are widely used for machine design and structural analyses. Although higher-order solid elements offer higher accuracy, the assembly routines often consume large amount of computational time and memory usage. In contrast, lower-order solid elements such as an 8-nod are simpler in programming implementation and consume less computational resources. However, they can produce problems of locking phenomena e.g. membrane and shear locking. Moreover, in a three-dimensional analysis using continuum solid elements, it is necessary to consider the stresses in the through-thickness direction, for example, in layered soil and foundation. This research aims to develop a modified strain-displacement finite element formulation that eliminates locking problems and generally applicable to both thick and thin threedimensional structures. The proposed formulation is based on the key concept of energy equivalence mapped between the global and natural curvilinear coordinates. The advantage of the proposed method is the ability to select a set of chosen strain functions that can be defined arbitrarily on the natural curvilinear coordinates.

Experimental Study and Finite Element Modeling of Workpiece Temperature in Finish Cylinder Boring

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Lei Chen ◽  
Bruce L. Tai ◽  
Juhchin A. Yang ◽  
Albert J. Shih
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Temperature Distribution ◽  
Heat Carrier ◽  
Machined Surface ◽  
Workpiece Temperature ◽  
Advantages And Disadvantages ◽  
Carrier Model ◽  
Inverse Heat Transfer ◽  
Cylindricity Error

Thermal expansion of the workpiece during cylinder boring process is one of the sources causing the bore cylindricity error. To study thermal expansion induced bore distortion, detailed workpiece temperature distribution in cylinder boring is required. Four finite element models, namely, the advection model, surface heat model, heat carrier model, and ring heat model, were developed to predict the workpiece temperature in cylinder boring. Cylinder boring experiments were conducted utilizing the tool–foil and embedded thermocouple experimental approaches to measure the workpiece temperature, predict the temperature distribution using the inverse heat transfer method, and evaluate the capability of the four models in terms of accuracy and efficiency. Results showed an accurate global temperature prediction for all models and a good correlation with the embedded thermocouple experimental measurements. Good correlation was also obtained between the tool–foil thermocouple measurement of machined surface temperature and model predictions. Advantages and disadvantages as well as applicable scenarios of each model were discussed. For studying detailed cylinder boring workpiece temperature, it is suggested to use the ring heat model to estimate the moving heat flux and the heat carrier model for local workpiece temperature calculation.

An Artificial Neural Network Approach for Generating High-Resolution Designs From Low-Resolution Input in Topology Optimization

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Nicholas Napier ◽  
Sai-Aksharah Sriraman ◽  
Huy T. Tran ◽  
Kai A. James
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Finite Element ◽  
Topology Optimization ◽  
Structural Integrity ◽  
Computational Cost ◽  
Computational Time ◽  
Boundary Edge ◽  
Fine Mesh ◽  
Artificial Neural

Abstract We address a central issue that arises within element-based topology optimization. To achieve a sufficiently well-defined material interface, one requires a highly refined finite element mesh; however, this leads to an increased computational cost due to the solution of the finite element analysis problem. By generating an optimal structure on a coarse mesh and using an artificial neural network to map this coarse solution to a refined mesh, we can greatly reduce computational time. This approach resulted in time savings of up to 85% for test cases considered. This significant advantage in computational time also preserves the structural integrity when compared with a fine-mesh optimization with limited error. Along with the savings in computational time, the boundary edges become more refined during the process, allowing for a sharp transition from solid to void. This improved boundary edge can be leveraged to improve the manufacturability of the optimized designs.

scholarly journals Finite element simulation and regression modeling of machining attributes on turning AISI 304 stainless steel

2021 ◽  
Vol 8 ◽  
pp. 24
Author(s):  
A. Mathivanan ◽  
M.P. Sudeshkumar ◽  
R. Ramadoss ◽  
Chakaravarthy Ezilarasan ◽  
Ganesamoorthy Raju ◽  
...  
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cutting Force ◽  
Cutting Speed ◽  
304 Stainless Steel ◽  
Computational Time ◽  
Depth Of Cut ◽  
Aisi 304 Stainless Steel ◽  
Machining Processes ◽  
Aisi 304

To-date, the usage of finite element analysis (FEA) in the area of machining operations has demonstrated to be efficient to investigate the machining processes. The simulated results have been used by tool makers and researchers to optimize the process parameters. As a 3D simulation normally would require more computational time, 2D simulations have been popular choices. In the present article, a Finite Element Model (FEM) using DEFORM 3D is presented, which was used to predict the cutting force, temperature at the insert edge, effective stress during turning of AISI 304 stainless steel. The simulated results were compared with the experimental results. The shear friction factor of 0.6 was found to be best, with strong agreement between the simulated and experimental values. As the cutting speed increased from 125 m/min to 200 m/min, a maximum value of 750 MPa stress as well as a temperature generation of 650 °C at the insert edge have been observed at rather higher feed rate and perhaps a mid level of depth of cut. Furthermore, the Response Surface Methodology (RSM) model is developed to predict the cutting force and temperature at the insert edge.

The prediction of vehicle vibration transmitted to the occupant using a modular transfer matrix

2021 ◽  
pp. 107754632199759
Author(s):  
Jianchun Yao ◽  
Mohammad Fard ◽  
John L Davy ◽  
Kazuhito Kato
Keyword(s):  
Finite Element ◽  
Transfer Matrix ◽  
Dynamic Performance ◽  
Complex Structure ◽  
Vehicle Body ◽  
Computational Time ◽  
Accurate Estimation ◽  
Finite Element Models ◽  
Transfer Matrices ◽  
Body Vibration

Industry is moving towards more data-oriented design and analyses to solve complex analytical problems. Solving complex and large finite element models is still challenging and requires high computational time and resources. Here, a modular method is presented to predict the transmission of vehicle body vibration to the occupants’ body by combining the numerical transfer matrices of the subsystems. The transfer matrices of the subsystems are presented in the form of data which is sourced from either physical tests or finite element models. The structural dynamics of the vehicle body is represented using a transfer matrix at each of the seat mounting points in three triaxial (X–Y–Z) orientations. The proposed method provides an accurate estimation of the transmission of the vehicle body vibration to the seat frame and the seated occupant. This method allows the combination of conventional finite element analytical model data and the experimental data of subsystems to accurately predict the dynamic performance of the complex structure. The numerical transfer matrices can also be the subject of machine learning for various applications such as for the prediction of the vibration discomfort of the occupant with different seat and foam designs and with different physical characteristics of the occupant body.

scholarly journals Stiffness Estimation and Equivalence of Boundary Conditions in FEM Models

2021 ◽  
Vol 11 (4) ◽  
pp. 1482
Author(s):  
Róbert Huňady ◽  
Pavol Lengvarský ◽  
Peter Pavelka ◽  
Adam Kaľavský ◽  
Jakub Mlotek
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Boundary Conditions ◽  
Model Updating ◽  
Element Model ◽  
Computational Time ◽  
Stiffness Coefficients ◽  
First Case ◽  
Numerical Approaches

The paper deals with methods of equivalence of boundary conditions in finite element models that are based on finite element model updating technique. The proposed methods are based on the determination of the stiffness parameters in the section plate or region, where the boundary condition or the removed part of the model is replaced by the bushing connector. Two methods for determining its elastic properties are described. In the first case, the stiffness coefficients are determined by a series of static finite element analyses that are used to obtain the response of the removed part to the six basic types of loads. The second method is a combination of experimental and numerical approaches. The natural frequencies obtained by the measurement are used in finite element (FE) optimization, in which the response of the model is tuned by changing the stiffness coefficients of the bushing. Both methods provide a good estimate of the stiffness at the region where the model is replaced by an equivalent boundary condition. This increases the accuracy of the numerical model and also saves computational time and capacity due to element reduction.

scholarly journals Image-based semi-multiscale finite element analysis using elastic subdomain homogenization

Meccanica ◽  
2021 ◽  
Author(s):  
J. Jansson ◽  
K. Salomonsson ◽  
J. Olofsson
Keyword(s):  
Finite Element ◽  
Analytical Method ◽  
Effective Properties ◽  
Reference Model ◽  
Computational Time ◽  
Component Level ◽  
Element Analysis ◽  
Model Fidelity ◽  
Multiscale Finite Element ◽  
Anisotropic Elastic

AbstractIn this paper we present a semi-multiscale methodology, where a micrograph is split into multiple independent numerical model subdomains. The purpose of this approach is to enable a controlled reduction in model fidelity at the microscale, while providing more detailed material data for component level- or more advanced finite element models. The effective anisotropic elastic properties of each subdomain are computed using periodic boundary conditions, and are subsequently mapped back to a reduced mesh of the original micrograph. Alternatively, effective isotropic properties are generated using a semi-analytical method, based on averaged Hashin–Shtrikman bounds with fractions determined via pixel summation. The chosen discretization strategy (pixelwise or partially smoothed) is shown to introduce an uncertainty in effective properties lower than 2% for the edge-case of a finite plate containing a circular hole. The methodology is applied to a aluminium alloy micrograph. It is shown that the number of elements in the aluminium model can be reduced by $$99.89\%$$ 99.89 % while not deviating from the reference model effective material properties by more than $$0.65\%$$ 0.65 % , while also retaining some of the characteristics of the stress-field. The computational time of the semi-analytical method is shown to be several orders of magnitude lower than the numerical one.

scholarly journals Practical Prediction of the Boil-Off Rate of Independent-Type Storage Tanks

2021 ◽  
Vol 9 (1) ◽  
pp. 36
Author(s):  
Dong-Ha Lee ◽  
Seung-Joo Cha ◽  
Jeong-Dae Kim ◽  
Jeong-Hyeon Kim ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Environmentally Friendly ◽  
Fuel Tank ◽  
Computational Time ◽  
Insulation Material ◽  
Element Analysis ◽  
Vertical Temperature Profile ◽  
Space Efficiency ◽  
Key Aspects

Because environmentally-friendly fuels such as natural gas and hydrogen are primarily stored in the form of cryogenic liquids to enable efficient transportation, the demand for cryogenic fuel (LNG, LH) ships has been increasing as the primary carriers of environmentally-friendly fuels. In such ships, insulation systems must be used to prevent heat inflow to the tank to suppress the generation of boil-off gas (BOG). The presence of BOG can lead to an increased internal pressure, and thus, its control and prediction are key aspects in the design of fuel tanks. In this regard, although the thermal analysis of the phase change through a finite element analysis requires less computational time than that implemented through computational fluid dynamics, the former is relatively more error-prone. Therefore, in this study, a cryogenic fuel tank to be incorporated in ships was established, and the boil-off rate (BOR), measured considering liquid nitrogen, was compared with that obtained using the finite element method. Insulation material with a cubic structure was applied to the cylindrical tank to increase the insulation performance and space efficiency. To predict the BOR through finite element analysis, the effective thermal conductivity was calculated through an empirical correlation and applied to the designed fuel tank. The calculation was predicted to within 1% of the minimum error, and the internal fluid behavior was evaluated by analyzing the vertical temperature profile according to the filling ratio.

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