Solidification Heat Transfer and Base Separation Analysis in the Casting of an Energetic Material in a Projectile

2005 ◽  
Author(s):  
Dawei Sun ◽  
S. Ravi Annapragada ◽  
Suresh V. Garimella ◽  
Sanjeev Sing
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Numerical Model ◽  
Residual Stresses ◽  
Energetic Materials ◽  
Energetic Material ◽  
Complex Geometries ◽  
Experimental Measurements ◽  
Linear Temperature ◽  
High Prandtl Number

This paper investigates the problem of base separation in the casting of energetic materials in a projectile. Special challenges that arise in casting high Prandtl number energetic materials in projectiles of complex geometries are addressed. A comprehensive numerical model is developed by integrating finite volume and finite element methods to analyze the thermal and flow fields as well as the residual stresses. The predictions, which are confirmed by experimental measurements, suggest that sustenance of a linear temperature profile along the projectile axis can eliminate base separation, and also reduce residual stresses in the final casting.

Optimization of Bulk Hgcdte Growth in a Directional Solidification Furnace by Numerical Simulation

1995 ◽  
Vol 398 ◽  
Author(s):  
A.V. Bune ◽  
D.C. Gillies ◽  
S.L. Lehoczky
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Finite Element ◽  
Crystal Growth ◽  
Numerical Model ◽  
Directional Solidification ◽  
Growth Conditions ◽  
Finite Element Code ◽  
Interface Shape ◽  
Solidification Furnace

ABSTRACTA numerical model of heat transfer by combined conduction, radiation and convection was developed using the FIDAP finite element code for NASA's Advanced Automated Directional Solidification Furnace (AADSF). The prediction of the temperature gradient in an ampoule with HgCdTe is a necessity for the evaluation of whether or not the temperature set points for furnace heaters and the details of cartridge design ensure optimal crystal growth conditions for this material and size of crystal. A prediction of crystal/melt interface shape and the flow patterns in HgCdTe are available using a separate complementary model.

Analysis of Strength and Residual Stresses in Filament Reinforced Aluminum Cylinders

1975 ◽  
Vol 97 (3) ◽  
pp. 192-198
Author(s):  
F. A. Simonen ◽  
N. C. Henderson ◽  
R. D. Winegardner ◽  
K. Specht
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Relative Increase ◽  
Burst Pressure ◽  
Experimental Measurements ◽  
Gas Cylinder ◽  
Proof Testing ◽  
Gas Cylinders

This paper describes a study of aluminum gas cylinders used in underwater manned vehicles. A determination was made of the relative increase in one cycle burst pressure and fatigue life of an existing aluminum gas cylinder when the sidewall was reinforced with fiberglass overwrap and prestressed by over pressurization. Detailed finite-element stress analyses were conducted to determine the operating stresses and also the residual stresses at the end cap-to-cylinder transition section which were a result of plastic deformation during proof testing. Calculated residual stresses were found to be consistent with experimental measurements. It was determined that the filament reinforcement both increased the vessel burst pressure and increased the vessel fatigue life through favorable prestress effects. Results of vessel fatigue and burst tests are presented and are compared with the predicted performance characteristics.

scholarly journals Implementing air-based thermally activated building systems in retrofitted tertiary buildings – Towards the proof of concept

2021 ◽  
Vol 2042 (1) ◽  
pp. 012075
Author(s):  
M Cézard ◽  
M Labat ◽  
S Lorente
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Numerical Model ◽  
Design Method ◽  
Proof Of Concept ◽  
General Design ◽  
Thermally Activated ◽  
Building Systems ◽  
Energy Balances

Abstract Here we document the design method of an air-based thermally activated building system (TABS) suited for the retrofitting of tertiary buildings, for cooling purposes mainly. The first phase of this work provides a general design and checks its consistency with the specifications of tertiary buildings by means of basic energy balances. Second, a numerical model of both the TABS and the room is developed under a finite element method multi-physics environment to better estimate the transient heat transfer for the proposed retrofitting solution. This results in the specifications for building at 1:1 scale prototype whose construction is documented.

Numerical Simulation for Thick-Walled Hollow Axle during Cross Wedge Rolling

2011 ◽  
Vol 337 ◽  
pp. 270-273 ◽  
Author(s):  
Yang Jiang ◽  
Bao Yu Wang ◽  
Zheng Huan Hu ◽  
Jian Guo Lin
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Model ◽  
Rolling Process ◽  
Cross Wedge Rolling ◽  
Finite Element Software ◽  
Temperature Distributions ◽  
Simulation Results ◽  
Deform 3D

The paper investigates a process of cross wedged rolling (CWR) for manufacturing thick-walled hollow axles. A finite element numerical model coupled deformation and heat transfer of CWR is established using commercial finite element software DEFORM-3D. The rolling process of hollow axle during CWR is simulated successfully. The stress, strain and temperature distributions of workpiece are obtained and analyzed. The simulation results show that forming thick-walled hollow axles through CWR is feasible.

Development of Predicted Stress and Strain during Conventional and after Mitigation of Welded Aluminium-Manganese Alloy

2013 ◽  
Vol 762 ◽  
pp. 596-601
Author(s):  
F. Soul ◽  
M. Ateeg
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Stress And Strain ◽  
Manganese Alloy ◽  
Element Analysis ◽  
Longitudinal Residual Stress ◽  
Mitigation Technique

The trend in automotive, aircraft, and marine industries is the increasing use of sheet materials to reduce weight in components and optimize materials performance. Welding is the main fabrication and assembly process in many of these industrial applications. However, in using thin-shell structures in such applications, welding may results in significant residual stresses and out-of-plane distortion. Transient thermal stresses, residual stresses, and distortion sometimes cause cracking and mismatching of joints. High tensile residual stresses are undesirable since they can contribute to fatigue failure. The analysis and measurement of temperature and stresses in component are often too complex to conduct in practise, and thus finite element models provide feasible approach to examine these matters. In this paper, finite element analysis has been performed using the ANSYS package to study the behaviour of longitudinal residual stress and strain in a welded thin aluminium-manganese alloy. The model presented simulates conventional welding and welding with the introduction of welding mitigation technique for enhancement of heat transfer, in which a trailing heat sink was applied. The thermal profiles obtained using the mitigation technique is completely different from those obtained in the conventional cooling. The localized transient residual stress and through-thickness strain after applying a cooling sink are discussed. The transient residual stress behaviour was highly affected by the modified temperature distribution and magnitude due to introducing the heat transfer enhancement.

Numerical and experimental research on engagement process of wet multi-plate friction clutches with groove consideration

2019 ◽  
Vol 233 (10) ◽  
pp. 1464-1482 ◽  
Author(s):  
Peng-hui Wu ◽  
Jin Xu ◽  
Xiao-Jun Zhou
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Numerical Model ◽  
Influencing Factors ◽  
Experimental Research ◽  
Revolution Speed ◽  
Heat Transfer Theory ◽  
Wet Clutch ◽  
Engagement Process ◽  
And Behavior

A numerical model is established to investigate the effects of the influencing factors such as design parameters and operating conditions on the performance and behavior of the engagement process of the wet clutch based on the Navier–Stokes equations, contact mechanics, and heat transfer theory. A finite element contact model called KE contact model is used to analyze the rough contact during engagement process and thermal effect on the viscosity is considered based on heat transfer theory. The integration of the grooving into the simulation and the method of coupled finite element by domain decomposition of groove and ungrooved areas are put forward to facilitate the analysis. The experimental results agree well with the numerical model which takes the normal pressure, the temperature of ATF, relative revolution speed, the permeability and the groove geometry into account. The results of numerical simulation and the experiment indicate that the applied pressure not only affects the engagement time, but also has influence on the value of the engagement torque. Besides, the engagement time is roughly proportional to the relative revolution speed. The influencing factors such as the temperature of ATF, the permeability, grooves, the torque judders and effects of PID control parameters are also discussed in the paper. The performance and behavior of the engagement of the wet clutch were studied by two methods of numerical calculation and experimental research, which make the working process of the wet clutch more detailed.

scholarly journals Characterization of Residual Stresses in 718 Turbine Discs by Neutron Diffraction and Finite Element Modelling

2011 ◽  
Vol 278 ◽  
pp. 102-107 ◽  
Author(s):  
Peter Staron ◽  
Ulrike Cihak ◽  
Helmut Clemens ◽  
Martin Stockinger ◽  
Andreas Schreyer
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Heat Transfer Coefficient ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Transfer Coefficient ◽  
Thin Plate ◽  
Stress Distributions ◽  
Element Simulation

The results of our investigations on residual stresses in commercially produced forged IN 718 compressor discs are reviewed. The residual stresses in the discs with a diameter of 320 mm and a thickness of up to 25 mm were studied using neutron diffraction to verify the predictions of a finite element simulation, which was used to model forging and cooling of the discs. In addition to the disc, a thin plate of the same material was also studied for testing the influence of specimen geometry on the model predictions. While the model results for the disc were not strongly influenced by the heat transfer coefficient, the stress distributions in the thin plate could only be predicted satisfactorily by using a temperature-dependent heat transfer coefficient that was derived from temperature measurements during quenching. Eventually, this led to an improvement of the FE simulation used for optimizing the production process.

Influence of Particle Attributes on Residual Stresses in Particulate Ceramic Composites

2016 ◽  
Vol 258 ◽  
pp. 190-193
Author(s):  
Kateřina Štegnerová ◽  
Luboš Náhlík ◽  
Raúl Bermejo ◽  
Pavel Hutař
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Model ◽  
Residual Stresses ◽  
Mechanical Behaviour ◽  
Three Dimensional ◽  
Ceramic Composites ◽  
Composite Matrix ◽  
Particle Properties ◽  
Fracture Processes

The contribution deals with the issue of residual stresses in particulate ceramic composites used in microelectronics. Residual stresses are developed in the composite due to cooling during manufacturing process. Different coefficients of thermal expansions of particles and matrix cause important residual stresses in the composite influencing their mechanical behaviour. The main aim of the paper is to determine influence of particle properties on magnitude and distribution of residual stresses in the composite matrix. Three dimensional numerical model was developed and finite element method (FEM) was used for numerical simulations. Results obtained contribute to a better understanding of residual stresses distribution and fracture processes in the studied type of composite.

scholarly journals Effect of Residual Stresses on the Stress Intensity Factor of Cracks in a Metal Matrix Composite: Numerical Analysis

2020 ◽  
Vol 22 (1) ◽  
pp. 119-132
Author(s):  
S. Ramdoum ◽  
F. Bouafia ◽  
B. Serier ◽  
H. Fekirini
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Numerical Model ◽  
Residual Stresses ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Three Dimensional ◽  
Internal Stresses ◽  
The Matrix

AbstractIn this work, the finite element method was used to determine the stress intensity factors as a function of crack propagation in metal matrix composite structure, A three-dimensional numerical model was developed to analyze the effect of the residual stresses induced in the fiber and in the matrix during cooling from the elaboration temperature at room temperature on the behavior out of the composite. Added to commissioning constraints, these internal stresses can lead to interfacial decohesion (debonding) or damage the matrix. This study falls within this context and allows cracks behavioral analysis initiated in a metal matrix composite reinforced by unidirectional fibers in ceramic. To do this, a three-dimensional numerical model was analyzed by method of finite element (FEM). This analysis is made according to several parameters such as the size of the cracking defects, its propagation, its interaction with the interface, the volume fraction of the fibers (the fiber-fiber interdistance), orientation of the crack and the temperature.

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