Modelling the pressure die casting process with the boundary element method: Die deformation model for flash prevention

1998 ◽  
Vol 212 (3) ◽  
pp. 197-215 ◽  
Author(s):  
J Milroy ◽  
S Hinduja ◽  
K Davey
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Die Casting ◽  
Injection Pressure ◽  
Casting Process ◽  
Operating Conditions ◽  
Deformation Model ◽  
The Individual ◽  
Pressure Die Casting ◽  
Element Method

In pressure die casting, the thermal loads, injection pressure and clamping forces cause the individual blocks of a die to deform. This deformation results in gaps between the interface surfaces which, if big enough and in the vicinity of the cavity, permit material to seep into the gaps, causing flash. This paper describes a thermoelastic model to predict the deformation of the die so that it can be machined to prevent flash. The model is based on the boundary element method and allows the use of linear isoparametric or quadratic subparametric elements. Each die block is analysed as a separate problem. To avoid the occurrence of flash, the model suggests the amounts that should be machined from each die block. The predicted deformation has been experimentally verified by measuring the profile of a test die using displacement transducers and die impressions. It is shown that there is good agreement between the predicted and experimental results for different operating conditions. By machining the amounts suggested by the model, the test die was run without flash at operating conditions that had previously resulted in flash.

Lattice Green’s Functions in Nonlinear Analysis of Defects

2006 ◽  
Vol 74 (4) ◽  
pp. 686-690 ◽  
Author(s):  
S. Haq ◽  
A. B. Movchan ◽  
G. J. Rodin
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Green's Functions ◽  
Model Problem ◽  
Green’S Functions ◽  
Plane Deformation ◽  
Deformation Model ◽  
Linear Region ◽  
Nonlinear Zone ◽  
Element Method

A method for analyzing problems involving defects in lattices is presented. Special attention is paid to problems in which the lattice containing the defect is infinite, and the response in a finite zone adjacent to the defect is nonlinear. It is shown that lattice Green’s functions allow one to reduce such problems to algebraic problems whose size is comparable to that of the nonlinear zone. The proposed method is similar to a hybrid finite-boundary element method in which the interior nonlinear region is treated with a finite element method and the exterior linear region is treated with a boundary element method. Method details are explained using an anti-plane deformation model problem involving a cylindrical vacancy.

An Experimental and Numerical Investigation into the Thermal Behavior of the Pressure Die Casting Process

1999 ◽  
Vol 122 (1) ◽  
pp. 90-99 ◽  
Author(s):  
S. Bounds ◽  
K. Davey ◽  
S. Hinduja
Keyword(s):  
Heat Transfer ◽  
Die Casting ◽  
Casting Process ◽  
Heat Extraction ◽  
Transfer Coefficients ◽  
Average Heat ◽  
Heat Transfer Coefficients ◽  
Die Casting Process ◽  
Pressure Die Casting ◽  
Element Method

The modeling of the pressure die casting process generally requires the specification of heat transfer coefficients at the surfaces of the die. The coefficients at the cavity-casting interface and at the cooling channel surfaces are of particular importance. In order to provide estimates for these heat transfer coefficients, the behavior of a specifically designed zinc alloy casting is investigated using a three dimensional thermal model whose predictions are supported by experimentally obtained results. The numerical model uses the boundary element method for the dies, as surface temperatures are of particular importance, and the finite element method for the casting, where the nonlinear material behavior makes this technique suitable. The experimental data comprises of thermocouple measurements of both die, casting, and coolant temperatures for three sets of operating conditions. These measurements are complemented by qualitative data of casting defects caused by incomplete solidification and thermal imaging temperature measurements. An experimental technique for obtaining average heat transfer coefficients for the casting–die interface is presented. Although the technique circumvents the need to place thermocouples in the casting and provides average heat transfer coefficients of sufficient accuracy for modeling purposes, it is not sufficiently responsive to provide accurate transient information. The presence of coolant boiling is detected by its effect on the rates of heat extraction. Heat transfer coefficients are determined for the cooling channels using a boiling model. Comparison between predicted and experimental rates of heat transfer to the coolant support the need for a boiling model. Good agreement is obtained between experimental and numerical predictions. [S1087-1357(00)00601-8]

A BOUNDARY-ELEMENT METHOD FOR ATOMIZATION OF A FINITE LIQUID JET

1995 ◽  
Vol 5 (6) ◽  
pp. 621-638 ◽  
Author(s):  
J. H. Hilbing ◽  
Stephen D. Heister ◽  
C. A. Spangler
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Liquid Jet ◽  
Element Method

Application of the Boundary Element Method and Modal Analysis to Tire Acoustics Problems

1993 ◽  
Vol 21 (2) ◽  
pp. 66-90 ◽  
Author(s):  
Y. Nakajima ◽  
Y. Inoue ◽  
H. Ogawa
Keyword(s):  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Radiation ◽  
Traffic Noise ◽  
Noise Prediction ◽  
Prediction System ◽  
Tire Noise ◽  
Acoustic Contribution ◽  
Element Method

Abstract Road traffic noise needs to be reduced, because traffic volume is increasing every year. The noise generated from a tire is becoming one of the dominant sources in the total traffic noise because the engine noise is constantly being reduced by the vehicle manufacturers. Although the acoustic intensity measurement technology has been enhanced by the recent developments in digital measurement techniques, repetitive measurements are necessary to find effective ways for noise control. Hence, a simulation method to predict generated noise is required to replace the time-consuming experiments. The boundary element method (BEM) is applied to predict the acoustic radiation caused by the vibration of a tire sidewall and a tire noise prediction system is developed. The BEM requires the geometry and the modal characteristics of a tire which are provided by an experiment or the finite element method (FEM). Since the finite element procedure is applied to the prediction of modal characteristics in a tire noise prediction system, the acoustic pressure can be predicted without any measurements. Furthermore, the acoustic contribution analysis obtained from the post-processing of the predicted results is very helpful to know where and how the design change affects the acoustic radiation. The predictability of this system is verified by measurements and the acoustic contribution analysis is applied to tire noise control.

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