Prediction of Thermal Displacements in Finite Element Tool Models

2001 ◽  
Author(s):  
Jörg Aßmus ◽  
Niels Wessel ◽  
Jürgen Kurths ◽  
Frank Weidermann ◽  
Jan Konvicka ◽  
...  
Keyword(s):  
Finite Element ◽  
Stable Process ◽  
Real Data ◽  
Thermal Displacement ◽  
Thermally Induced ◽  
The Past ◽  
Alternating Conditional Expectation ◽  
Thermal Displacements ◽  
Displacement Based ◽  
Ace Algorithm

Abstract Precision and productivity are very important criteria for the evaluation of modular tool systems and require a thermally stable process with tolerances in the micrometer range. During the past decades there has been an increasing interest in compensating thermally induced errors. In this paper we investigate wheather a prediction of thermal displacement based on a nonlinear regression analysis is possible, namely using the alternating conditional expectation algorithm (ACE) introduced by Breiman and Friedman, 1985. The data we are analyzing were generated by two different finite element spindle models of modular tool systems. As the main result we find that the ACE-algorithm is a powerful tool to model the relation between temperatures and displacements. It could also be a promising approach to handle well-known hysteresis effects. Limitations of this study are the model restricted results, next our findings have to be validated on real data.

MODELING THERMAL DISPLACEMENTS IN MODULAR TOOL SYSTEMS

2004 ◽  
Vol 14 (06) ◽  
pp. 2125-2132 ◽  
Author(s):  
NIELS WESSEL ◽  
JÖRG AßMUS ◽  
UDO SCHWARZ ◽  
JÜRGEN KURTHS ◽  
FRANK WEIDERMANN ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Measured Data ◽  
Data Sets ◽  
Nonlinear Regression Analysis ◽  
Thermally Induced ◽  
Alternating Conditional Expectation ◽  
Maximal Correlation ◽  
Thermal Displacements ◽  
Manufacturing Accuracy ◽  
Ace Algorithm

There is an important interest in compensating thermally induced errors of modular tool systems to improve the manufacturing accuracy. In this paper, we test the hypothesis whether we can predict such thermal displacements by using a nonlinear regression analysis, namely the alternating conditional expectation algorithm (ACE [Breiman & Friedman, 1985]), reliably. The data analyzed were generated by two different finite element spindle models of modular tool systems. As the main result, we find that the ACE-algorithm is a powerful tool to model the relation between temperatures and displacements. The maximal correlation is larger than 0.999 in both cases, which demonstrates the suitability of the ACE algorithm. Furthermore, preconditions for the applicability of this approach, such as the length and the support of measured data sets, are studied. Hence, this approach seems to be promising for the application to real modular tool systems.

Implementation of Likhachev’s Model into a Finite Element Program

2013 ◽  
Vol 738-739 ◽  
pp. 160-164 ◽  
Author(s):  
Patrick Terriault ◽  
Vladimir Brailovski
Keyword(s):  
Finite Element ◽  
Stress And Strain ◽  
Complex Behavior ◽  
Element Analysis ◽  
Finite Element Program ◽  
The Past ◽  
Design Engineers ◽  
Element Program ◽  
Displacement Based ◽  
Proportional Controller

Shape memory alloys have become very popular over the past few decades, mainly as actuators or superelastic devices. Their complex behavior complicates the design process of these applications, and several models have been developed to assist design engineers in this endeavor. One of these models, the structure-analytical theory proposed by Likhachev, is particularly attractive because it is physically grounded and capable of dealing with tensorial stress and strain states. Unfortunately, its stress-controlled formulation has hindered its implementation in displacement-based finite element programs. This paper presents an adaptation of Likhachev’s model leading to a strain-controlled formulation based on an iterative algorithm and a proportional controller. The resulting model is implemented in ANSYS and a simple finite element analysis is carried out to illustrate its appropriate functioning.

Uneven Wear of Vehicle Tires

1993 ◽  
Vol 21 (4) ◽  
pp. 202-219 ◽  
Author(s):  
M. H. Walters
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Techniques ◽  
Lateral Stiffness ◽  
General Increase ◽  
Element Analysis ◽  
The Past ◽  
Uneven Wear

Abstract Advances in tire construction have led to major increases in tire life over the past twenty years, mainly by increasing the lateral stiffness and thus reducing slip during cornering. However, this general increase in tire life has tended to highlight the problem of uneven wear. In the present paper, three new experimental techniques are described which have been developed to study treadwear distributions. These techniques are evaluated and their results compared with a finite element analysis. Taken together, they indicate some of the causes of uneven wear and may be used to identify tire design and service features which contribute to uneven wear.

Experience

2021 ◽  
Vol 13 (1) ◽  
pp. 1-16
Author(s):  
Michela Fazzolari ◽  
Francesco Buccafurri ◽  
Gianluca Lax ◽  
Marinella Petrocchi
Keyword(s):  
Relative Frequency ◽  
Service Providers ◽  
Real Data ◽  
Online Reviews ◽  
Purchase Decision ◽  
The Past ◽  
Supervised Classifiers ◽  
Relative Frequency Distribution ◽  
Opinion Spam ◽  
Fake Reviews

Over the past few years, online reviews have become very important, since they can influence the purchase decision of consumers and the reputation of businesses. Therefore, the practice of writing fake reviews can have severe consequences on customers and service providers. Various approaches have been proposed for detecting opinion spam in online reviews, especially based on supervised classifiers. In this contribution, we start from a set of effective features used for classifying opinion spam and we re-engineered them by considering the Cumulative Relative Frequency Distribution of each feature. By an experimental evaluation carried out on real data from Yelp.com, we show that the use of the distributional features is able to improve the performances of classifiers.

scholarly journals Finite Element Analysis of Mandibular Anterior Teeth with Healthy, but Reduced Periodontium

2021 ◽  
Vol 11 (9) ◽  
pp. 3824
Author(s):  
Ioana-Andreea Sioustis ◽  
Mihai Axinte ◽  
Marius Prelipceanu ◽  
Alexandra Martu ◽  
Diana-Cristala Kappenberg-Nitescu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Real Data ◽  
Element Analysis ◽  
Anterior Teeth ◽  
Applied Forces ◽  
Orthodontic Forces

Finite element analysis studies have been of interest in the field of orthodontics and this is due to the ability to study the stress in the bone, periodontal ligament (PDL), teeth and the displacement in the bone by using this method. Our study aimed to present a method that determines the effect of applying orthodontic forces in bodily direction on a healthy and reduced periodontium and to demonstrate the utility of finite element analysis. Using the cone-beam computed tomography (CBCT) of a patient with a healthy and reduced periodontium, we modeled the geometric construction of the contour of the elements necessary for the study. Afterwards, we applied a force of 1 N and a force of 0.8 N in order to achieve bodily movement and to analyze the stress in the bone, in the periodontal ligament and the absolute displacement. The analysis of the applied forces showed that a minimal ligament thickness is correlated with the highest value of the maximum stress in the PDL and a decreased displacement. This confirms the results obtained in previous clinical practice, confirming the validity of the simulation. During orthodontic tooth movement, the morphology of the teeth and of the periodontium should be taken into account. The effect of orthodontic forces on a particular anatomy could be studied using FEA, a method that provides real data. This is necessary for proper treatment planning and its particularization depends on the patient’s particular situation.

Research on Thermally Induced Deformation of Reinforcing Plate Based on Finite Element Simulation

2012 ◽  
Vol 197 ◽  
pp. 139-143
Author(s):  
Hua Bai ◽  
Yi Du Zhang
Keyword(s):  
Finite Element ◽  
Ambient Temperature ◽  
Finite Element Simulation ◽  
Temperature Change ◽  
Large Scale ◽  
Machining Process ◽  
Reinforcement Structure ◽  
Thermally Induced ◽  
Finite Element Software ◽  
Element Simulation

The change of ambient temperature will cause deformation during the machining process of large-scale aerospace monolithic component. Based on finite element simulation, thermally induced deformation of reinforcing plate is studied in such aspects as reinforcement structure, clamping method and temperature change, and contact function in finite element software is used to simulate the unilateral constraint between workpiece and worktable. The results indicate that reinforcing plate will produce warping deformation due to the change of ambient temperature. Different reinforcement structures and clamping methods have important influence on the deformation positions and degrees, and the deformation is proportional to the temperature change.

Pipeline Dent Management Program

2002 ◽  
Author(s):  
Scott D. Ironside ◽  
L. Blair Carroll
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Selection Process ◽  
Element Model ◽  
Field Trials ◽  
Management Program ◽  
Operating Conditions ◽  
Published Data ◽  
Element Analysis ◽  
The Past

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.

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