Incorporating Neural Network Material Models Within Finite Element Analysis for Rheological Behavior Prediction

2006 ◽  
Vol 129 (1) ◽  
pp. 58-65 ◽  
Author(s):  
B. Scott Kessler ◽  
A. Sherif El-Gizawy ◽  
Douglas E. Smith

The accuracy of a finite element model for design and analysis of a metal forging operation is limited by the incorporated material model’s ability to predict deformation behavior over a wide range of operating conditions. Current rheological models prove deficient in several respects due to the difficulty in establishing complicated relations between many parameters. More recently, artificial neural networks (ANN) have been suggested as an effective means to overcome these difficulties. To this end, a robust ANN with the ability to determine flow stresses based on strain, strain rate, and temperature is developed and linked with finite element code. Comparisons of this novel method with conventional means are carried out to demonstrate the advantages of this approach.

Author(s):  
B. Scott Kessler ◽  
A. Sherif El-Gizawy ◽  
Douglas E. Smith

The accuracy of a finite element model for design and analysis of a metal forging operation is limited by the incorporated material model’s ability to predict deformation behavior over a wide range of operating conditions. Current rheological models prove deficient in several respects due to the difficulty in establishing complicated relations between many parameters. More recently, artificial neural networks (ANN) have been suggested as an effective means to overcome these difficulties. To this end, a robust ANN with the ability to determine flow stresses based on strain, strain rate, and temperature is developed and linked with finite element code. Comparisons of this novel method with conventional means are carried out to demonstrate the advantages of this approach.


Author(s):  
B. Scott Kessler ◽  
A. Sherif El-Gizawy

The accuracy of a finite element model for design and analysis of a metal forging operation is limited by the incorporated material model’s ability to predict deformation behavior over a wide range of operating conditions. Current rheological models prove deficient in several respects due to the difficulty in establishing complicated relations between many parameters. More recently, artificial neural networks (ANN) have been suggested as an effective means to overcome these difficulties. In the present work, a previously developed ANN with the ability to determine flow stresses based on strain, strain rate, and temperature is incorporated with finite element code. Utilizing this linked approach, a preliminary model for forging an aluminum wheel is developed. This novel method, along with a conventional approach, is then measured against the forging process as it is currently performed in actual production.


Author(s):  
Scott D. Ironside ◽  
L. Blair Carroll

Enbridge Pipelines Inc. operates the world’s longest and most complex liquids pipeline network. As part of Enbridge’s Integrity Management Program In-Line Inspections have been and will continue to be conducted on more than 15,000 km of pipeline. The Inspection Programs have included using the most technologically advanced geometry tools in the world to detect geometrical discontinuities such as ovality, dents, and buckles. During the past number of years, Enbridge Pipelines Inc. has been involved in developing a method of evaluating the suitability of dents in pipelines for continued service. The majority of the work involved the development of a method of modeling the stresses within a dent using Finite Element Analysis (FEA). The development and validation of this model was completed by Fleet Technology Limited (FTL) through several projects sponsored by Enbridge, which included field trials and comparisons to previously published data. This model combined with proven fracture mechanics theory provides a method of determining a predicted life of a dent based on either the past or future operating conditions of the pipeline. CSA Standard Z662 – Oil and Gas Pipeline Systems provides criteria for the acceptability of dents for continued service. There have been occurrences, however, where dents that meet the CSA acceptability criteria have experienced failure. The dent model is being used to help define shape characteristics in addition to dent depth, the only shape factor considered by CSA, which contribute to dent failure. The dent model has also been utilized to validate the accuracy of current In-Line Inspection techniques. Typically a dent will lose some of its shape as the overburden is lifted from the pipeline and after the indentor is removed. Often there can be a dramatic “re-rounding” that will occur. The work included comparing the re-rounded dent shapes from a Finite Element model simulating the removal of the constraint on the pipe to the measured dent profile from a mold of the dent taken in the field after it has been excavated. This provided a measure of the accuracy of the tool. This paper will provide an overview of Enbridge’s dent management program, a description of the dent selection process for the excavation program, and a detailed review of the ILI validation work.


2014 ◽  
Vol 945-949 ◽  
pp. 1143-1149
Author(s):  
Hai Xia Sun ◽  
Hua Kai Wei ◽  
Xiao Fang Zhao ◽  
Jia Rui Qi

The finite element model of the concrete mixing truck’s frame is builded by using shell as basic element, and the process of building the finite element model of the balance suspension is introduced in detail. Based on this, frame’s stress on five types of typical operating conditions are calculated by using the finite element analysis software, NASTRAN, and results can show the dangerous position and the maximum stress position on the frame. The analysis result on structural strength can provide the basis for further improving the frame structure.


Author(s):  
Yin Gao ◽  
Mike McHenry ◽  
Brad Kerchof

Cut spike fasteners, used with conventional AREMA rolled tie plates and solid sawn timber ties, are the most common tie and fastener system used on North American freight railroads. Cut spikes are also used to restrain tie plates that incorporate an elastic rail fastener — that is, an elastic clip that fastens the rail to the tie plate. Elastic fasteners have been shown to reduce gage widening and decrease the potential for rail roll compared to cut spike-only systems. For this reason, elastic fastener systems have been installed in high degree curves on many railroads. Recent observations on one Class I railroad have noted broken cut spikes when used with these types of tie plates in mountainous, high degree curve territory. Broken screw spikes and drive spikes on similar style plates have also been observed. In this paper, a simulation method that integrates a vehicle-track system dynamics model, NUCARS®, with a finite element analysis model is used to investigate the root causes of the broken spikes. The NUCARS model consists of a detailed multibody train, wheel-rail contact parameters, and track model that can estimate the dynamic loading environment of the fastening system. For operating conditions in tangent and curve track, this loading environment is then replicated in a finite element model of the track structure — ties, tie plates, and cut spikes. The stress contours of the cut spikes generated in these simulations are compared to how cut spikes have failed in revenue service. The tuning and characterization of both the vehicle dynamics multibody model and the finite element models are presented. Additionally, the application of this approach to other types of fastening systems and spike types is discussed. Preliminary results have identified a mechanism involving the dynamic unloading of the tie plate-to-tie interface due to rail uplift ahead of the wheel and the resulting transfer of net longitudinal and lateral forces into the cut spikes. Continued analysis will attempt to confirm this mechanism and will focus on the severity of these stresses, the effect of increased grade, longitudinal train dynamics, braking forces, and curvature.


2020 ◽  
Vol 10 (1) ◽  
pp. 44-54
Author(s):  
Sneha Sanap ◽  
Vinit Swami ◽  
Amol Patil ◽  
Shailesh Deshmukh ◽  
Veera Bhosale

Introduction: Orthodontic correction of Angle’s class II molar relation has, for long, been one of the challenges in orthodontics, with various researchers attempting to correct the class II molar relationship by diverse methods. One of the techniques that has gained popularity in recent times is maxillary arch distalization by infrazygomatic screws and miniscrews. The objective of the study is to measure and compare the amount of maxillary arch distalization and its effects, on adjacent teeth, by varying the positions of mini-implants by Finite Element Analysis. Materials & Method: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. In this study, three models were prepared. Model-1: The (miniscrews) were placed between upper first and second premolar, and between second premolar and first molar bilaterally. Model-2: Infrazygomatic screws was placed between upper first and second molar bilaterally. Model-3: Infrazygomatic screws was placed on the mesio-buccal root of upper first molar bilaterally. The displacement of each tooth was calculated on x, y, and z axes when 200 gm of force was applied on each side. Result: Maximum amount of maxillary arch distalization was seen when infrazygomatic screws placed between upper first and second molar in model-2. Whereas maximum amount of maxillary arch intrusion and less distalization was observed when miniscrews placed between upper first premolar and second premolar and in between second premolar and upper first molar in model-1. The difference was statistically significant (p=0.005*). There was no bucco-palatal rotation of teeth observed among all three finite element models. Conclusion: Thus infrazygomatic screws and miniscrews are the effective means of maxillary arch distalization for the correction of Class II malocclusion.


Author(s):  
Francesco Frendo ◽  
Vincenzo Sarra ◽  
Michele Spina

In the present work, the operating conditions of “side-load” springs, which are typically employed in McPherson suspensions, were analysed by finite element analysis. The finite element model, including the spring and the upper and lower spring seats, is firstly described in the paper; the spring geometry was accurately obtained by a reverse engineering procedure based on two video cameras and a video projector. Surface to surface contact elements were defined between spring and seats; the initial assembling phase of the spring between the seats was also included in the finite element analysis. The experimental rig, employed for spring characterisation, and the performed numerical analyses are then presented; results are discussed in comparison with experimental data, in terms of spring characteristic, side-load force and thrust axis spatial position, as a function of spring compression. A fully satisfactory agreement was generally observed between numerical results and experiments. The effect of lower spring seat orientation on results was also investigated by numerical analysis. A higher inclination of the lower seat appeared to increase the side-load force; at the same time, for a given configuration, the thrust axis orientation, remained almost constant during suspension compression.


Author(s):  
Andrew R. Thoreson ◽  
James J. Stone ◽  
Kurtis L. Langner ◽  
Jay Norton ◽  
Bor Z. Jang

Numerous techniques for fabricating tissue engineering scaffolds have been proposed by researchers covering many disciplines. While literature regarding properties and efficacy of scaffolds having a single set of design parameters is abundant, characterization studies of scaffold structures encompassing a wide range of design parameters are limited. A Precision Extrusion Deposition (PED) system was developed for fabricating poly-ε-caprolactone (PCL) tissue scaffolds having interconnected pores suitable for cartilage regeneration. Scaffold structures fabricated with three-dimensional printing methods are periodic and are readily modeled using Computer Aided Design (CAD) software. Design parameters of periodic scaffold architectures were identified and incorporated into CAD models with design parameters over the practical processing range represented. Solid models were imported into a finite element model simulating compression loading. Model deformation results were used to identify apparent modulus of elasticity of the structure. PCL scaffold specimens with design parameters within the modeled range were fabricated and subjected to compression testing to physically characterize scaffold modulus. Results of physical testing and finite element models were compared to determine effectiveness of the method.


Author(s):  
Christopher Bertagne ◽  
Peyman Moghadas ◽  
Richard Malak ◽  
Darren Hartl

This paper demonstrates a framework for integrating full feedback control with a high-fidelity finite element model in order to simulate control of morphing structures. Most of the previous finite element simulations involving control of morphing structures consider the effects of the controller, but do not incorporate true feedback control. Additionally, when feedback control is considered, numerical models other than finite element analysis are used. Thus, a trade-off must be made between a high-fidelity model and consideration of feedback control. In this work, these aspects are unified to create a tool that can simulate real-time feedback control of a finite element model. The framework itself consists of two components: the finite element model and the controller. The finite element model must be capable of varying external loads as the solution evolves in time. In this paper, the finite element model is implemented in ABAQUS. The controller component is written in Python. In order to ensure the framework is suitable for a wide range of applications, no assumptions are made regarding the natures of the finite element model or the control architecture. Additionally, the components are designed to be modular. For example, simulating different controller architectures does not require alteration of the finite element model. The result is a highly flexible framework that is particularly well-suited for validating and demonstrating controllers on high-fidelity models.


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