A Numerical Solution of the Inverse Problem for Thermoforming Processes Using Finite Element Analysis

2000 ◽  
Author(s):  
Chao-Hsin Wang ◽  
Herman F. Nied
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Initial Temperature ◽  
Initial Conditions ◽  
Heat Transfer Analysis ◽  
Element Analysis ◽  
Initial Temperature Distribution ◽  
Final Thickness ◽  
Temperature Distributions

Abstract Finite element analysis of thermoforming simulation based on isothermal as well as non-isothermal initial conditions has been applied successfully for predicating final thickness distributions. For these simulations, it is assumed that the initial sheet temperature is known and does not change significantly during forming at a rapid stretch rate. For a non-isothermal analysis, the temperature dependent material properties are necessary. In this paper sample results are presented for the so-called inverse thermoforming problem, where an initial temperature distribution is sought numerically that will result in a specific final thickness distribution. Thus, a finite element simulation is combined with an iterative algorithm to obtain inverse solutions for a thermoformed part. In this example, the required initial temperature distributions that result in a uniform final thickness are determined for a thermoformed part. It is shown that the calculated results are quite sensitive to perturbations in the specified initial temperature profile and thus the practical application of optimal temperature distributions may require high precision thermal sensors and controls. This initial temperature distribution can then be used for the determination of desired heating patterns on zone-controlled heaters of a thermoforming machine using transient heat transfer analysis.

Analysis of Temperature Distribution on Warm Forming of Aluminum-Magnesium Alloy

2011 ◽  
Vol 264-265 ◽  
pp. 329-336 ◽  
Author(s):  
Fahrettin Ozturk ◽  
Mehmet A. Arslan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Initial Temperature ◽  
Warm Forming ◽  
Mg Alloy ◽  
Element Analysis ◽  
Aluminum Magnesium Alloy

In this study, a temperature distribution of 5083-O aluminum-magnesium (Al-Mg) alloy is analyzed at various die and blank initial temperature conditions using finite element analysis approach. Temperature distribution results of the blank reveal that the dies must be heated to predetermined temperatures for successful warm forming, even the blank is kept at room temperature.

Lifetime Prediction of Tires with Regard to Oxidative Aging5

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Superposition Principle ◽  
Accelerated Aging ◽  
Material Model ◽  
Aging Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Reaction Processes

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.

Hysteresis Heating of Railroad Bearing Thermoplastic Elastomer Suspension Element

2017 ◽  
Author(s):  
Oscar O. Rodriguez ◽  
Arturo A. Fuentes ◽  
Constantine Tarawneh ◽  
Robert E. Jones
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Steady State ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Internal Heat ◽  
Thermoplastic Elastomer ◽  
Internal Heat Generation ◽  
Element Analysis ◽  
Railroad Bearing

Thermoplastic elastomers (TPE’s) are increasingly being used in rail service in load damping applications. They are superior to traditional elastomers primarily in their ease of fabrication. Like traditional elastomers they offer benefits including reduction in noise emissions and improved wear resistance in metal components that are in contact with such parts in the railcar suspension system. However, viscoelastic materials, such as the railroad bearing thermoplastic elastomer suspension element (or elastomeric pad), are known to develop self-heating (hysteresis) under cyclic loading, which can lead to undesirable consequences. Quantifying the hysteresis heating of the pad during operation is therefore essential to predict its dynamic response and structural integrity, as well as, to predict and understand the heat transfer paths from bearings into the truck assembly and other contacting components. This study investigates the internal heat generation in the suspension pad and its impact on the complete bearing assembly dynamics and thermal profile. Specifically, this paper presents an experimentally validated finite element thermal model of the elastomeric pad and its internal heat generation. The steady-state and transient-state temperature profiles produced by hysteresis heating of the elastomer pad are developed through a series of experiments and finite element analysis. The hysteresis heating is induced by the internal heat generation, which is a function of the loss modulus, strain, and frequency. Based on previous experimental studies, estimations of internally generated heat were obtained. The calculations show that the internal heat generation is impacted by temperature and frequency. At higher frequencies, the internally generated heat is significantly greater compared to lower frequencies, and at higher temperatures, the internally generated heat is significantly less compared to lower temperatures. However, during service operation, exposure of the suspension pad to higher loading frequencies above 10 Hz is less likely to occur. Therefore, internal heat generation values that have a significant impact on the suspension pad steady-state temperature are less likely to be reached. The commercial software package ALGOR 20.3TM is used to conduct the thermal finite element analysis. Different internal heating scenarios are simulated with the purpose of obtaining the bearing suspension element temperature distribution during normal and abnormal conditions. The results presented in this paper can be used in the future to acquire temperature distribution maps of complete bearing assemblies in service conditions and enable a refined model for the evolution of bearing temperature during operation.

Study of Limiting Dome Height and Temperature Distribution in Warm Forming of ASS304 Using Finite Element Analysis

2017 ◽  
Vol 4 (2) ◽  
pp. 957-965
Author(s):  
Chadaram Srinivasu ◽  
Swadesh Kumar Singh ◽  
Gangadhar Jella ◽  
Lade Jayahari ◽  
Nitin Kotkunde
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Warm Forming ◽  
Dome Height ◽  
Element Analysis

Finite element analysis for temperature distributions in a cold forging

2013 ◽  
Vol 27 (10) ◽  
pp. 2979-2984
Author(s):  
Dongbum Kim ◽  
Sungwook Kim ◽  
Inchul Song ◽  
Byungcheol Jeon ◽  
Inhwan Lee ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cold Forging ◽  
Element Analysis ◽  
Temperature Distributions

scholarly journals Three-dimensional finite element simulation of residual stresses in UIC60 rails during the quenching process

2017 ◽  
Vol 21 (3) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nejad Masoudi ◽  
Mahmoud Shariati ◽  
Khalil Farhangdoost
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Analysis Model ◽  
Element Analysis ◽  
Quenching Process ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The aim of this paper is to develop means to predict accurately the residual stresses due to quenching process of an UIC60 rail. A 3-D non-linear stress analysis model has been applied to estimate stress fields of an UIC60 rail in the quenching process. A cooling mechanism with water spray is simulated applying the elastic-plastic finite element analysis for the rail. The 3-D finite element analysis results of the studies presented in this paper are needed to describe the initial conditions for analyses of how the service conditions may act to change the as-manufactured stress field.

Thermal compensation using the hybrid metrology approach compared to traditional scaling

2017 ◽  
Vol 232 (13) ◽  
pp. 2364-2374
Author(s):  
David Ross-Pinnock ◽  
Glen Mullineux
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Expansion ◽  
Temperature Measurement ◽  
Large Scale ◽  
Element Analysis ◽  
Linear Temperature ◽  
Temperature Distributions ◽  
Finite Element Analysis Simulation ◽  
Uniform Scaling

Control of temperature in large-scale manufacturing environments is not always practical or economical, introducing thermal effects including variation in ambient refractive index and thermal expansion. Thermal expansion is one of the largest contributors to measurement uncertainty; however, temperature distributions are not widely measured. Uncertainties can also be introduced in scaling to standard temperature. For more complex temperature distributions with non-linear temperature gradients, uniform scaling is unrealistic. Deformations have been measured photogrammetrically in two thermally challenging scenarios with localised heating. Extended temperature measurement has been tested with finite element analysis to assess a compensation methodology for coordinate measurement. This has been compared to commonly used uniform scaling and has outperformed this with a highly simplified finite element analysis simulation in scaling a number of coordinates at once. This work highlighted the need for focus on reproducible temperature measurement for dimensional measurement in non-standard environments.

Numerical Simulation on Temperature Field in Single-Layer Laser Cladding Using Coaxial Inside-Beam Powder Feeding

2010 ◽  
Vol 426-427 ◽  
pp. 151-155 ◽  
Author(s):  
Ming Di Wang ◽  
Shi Hong Shi ◽  
Dun Wen Zuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Laser Cladding ◽  
Moving Boundary ◽  
Single Layer ◽  
Layer By Layer ◽  
Analysis Model ◽  
Element Analysis ◽  
Powder Feeding

For the disadvantages of the lateral powder feeding and multi-lateral coaxial powder feeding process in laser cladding rapid prototyping process, a new process of hollow focusing laser, powder tube being middle and inside-beam powder feeding is put forward, which can be especially apply in laser cladding. In this paper, the finite element analysis model of temperature of the laser cladding using inside-beam powder feeding is established, temperature distribution of the single-layer in laser cladding is researched, which is theoretically useful for controlling the quality of microstructure and to prevent the cracks. When adopting finite element analysis software, Ansys, the layer unit is acted layer-by-layer, the full simulation of real cladding deposition process will be realized if moving boundary. Finally, some experiments validate the simulation results. Compared with the original mode, it can be found that if adopting the system of the laser cladding rapid manufacturing using inside-beam powder feeding, the temperature distribution is different and it will lead to a denser microstructure.

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