Thermoelastic Whirling Analysis of Cylinders During Grinding

2009 ◽  
Author(s):  
Erno Keskinen ◽  
Timo Karvinen ◽  
Vladimir Dospel ◽  
Mika To¨ho¨nen ◽  
Teppo Syrja¨nen ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Thermal Effects ◽  
Time Integration ◽  
Interaction Mechanism ◽  
Thermoelastic Problem ◽  
Work Piece ◽  
Bending Vibrations ◽  
Thermal Deformations ◽  
Eigenfunction Basis ◽  
Modal Coordinates

Cylinder grinding has been the subject for an intensive research, because delay-type resonances, commonly known as chatter-vibrations, have been reason for serious surface quality problems in industry [1]. As a result of this activity there is available a simulation platform, on which the complete grinding process including delay-resonances can be driven [2]. This platform consists of models for the grinder, for the cylindrical work piece and for the stone-cylinder grinding contact. The elastic cylinder model is based on analytical eigenfunctions in bending vibrations, which basis has been used to present the rotordynamic equations of cylinder in modal coordinates. Stone-cylinder interaction mechanism has been derived by combining the rules of mass and momentum transfer in the material removal process. The contribution of this paper is to update the platform to include the thermal effects of the work body. Following the method to use the eigenfunctions of a non-supported beam to describe the rotordynamic motion of the work body, a promising method could be to use in a similar way the eigenfunctions of a thermally isolated cylinder to solve the temperature distribution of the cylinder. The temperature distribution and terms related to the non-homogeneous boundary conditions will then be the input to the thermoelastic problem. It can be shown that the eigenfunction basis consists of trigonometric functions in axial and circumferential directions while the radial eigenfunctions are Bessel functions. The stone-cylinder interface has to be updated also to include thermal effects. A portion of the mechanical power is transferred to the work piece. The rest goes to the stone, to the material, which is removed and to the cutting coolant. On the other hand, thermal deformations modify the grinding forces, which are loading the work piece. The solution of the coupled thermal and thermoelastic problem will be done in terms of modal coordinates corresponding to the eigenfunction basis. This leads to numerical time integration of two groups of differential equations, the solution of which can be used to perform the temperature distributions and the corresponding thermal deformations.

Thermoelastic Response of Thin-Walled Cylindrical Shell Under the Effect of Moving Point Load and Heat Source

2011 ◽  
Author(s):  
Erno Keskinen ◽  
Timo Karvinen ◽  
Vladimir Dospel ◽  
Michel Cotsaftis
Keyword(s):  
Cylindrical Shell ◽  
Temperature Distribution ◽  
Thermal Effects ◽  
Circular Cylindrical Shell ◽  
Thermoelastic Problem ◽  
Work Piece ◽  
Thermal Deformations ◽  
Thin Walled ◽  
Eigenfunction Basis ◽  
Modal Coordinates

Cylinder grinding has been the subject of an intensive research, because delay-type resonances, commonly known as chatter-vibrations, have been reason for serious surface quality problems in industry [1]. As a result of this activity it has been developed a simulation platform, on which the complete grinding process including delay-resonances can be driven [2]. This platform consists of models for the grinder, for the cylindrical work piece and for the stone-cylinder grinding contact. The elastic cylinder model is based on analytical eigenfunctions in bending vibrations, which basis has been used to present the rotordynamic equations of cylinder in modal coordinates. Stone-cylinder interaction mechanism has been derived by combining the rules of mass and momentum transfer in the material removal process. The contribution of this paper is to update the platform to include the thermal effects of the work body undergoing shell deformations. Following the method to use the eigenfunctions of a thin-walled circular cylindrical shell to describe the rotordynamic motion of the work body, a promising method could be to use in a similar way the eigenfunctions of a thermally isolated cylinder to solve the temperature distribution of the cylinder. The temperature distribution and terms related to the non-homogeneous boundary conditions will then be the input to the thermoelastic problem. It can be shown that the eigenfunction basis consists of trigonometric functions in axial and circumferential directions while the radial eigenfunctions are Bessel functions. The stone-cylinder interface has to be updated also to include thermal effects. A portion of the mechanical power is transferred to the work piece. The rest goes to the stone, to the material, which is removed and to the cutting coolant. On the other hand, thermal deformations modify the grinding forces, which are loading the work piece. The solution of the coupled thermal and thermoelastic problem will be done in terms of modal coordinates corresponding to the eigenfunction basis. This leads to numerical time integration of two groups of differential equations, the solution of which can be used to perform the temperature distributions and the corresponding thermal deformations.

scholarly journals A TWO-DIMENSIONAL THERMODYNAMIC MODEL TO PREDICT HEART THERMAL RESPONSE DURING OPEN CHEST PROCEDURES

2016 ◽  
Vol 15 (1) ◽  
pp. 44
Author(s):  
F. G. Dias ◽  
J. V. C. Vargas ◽  
M. L. Brioschi
Keyword(s):  
Cardiac Surgery ◽  
Temperature Distribution ◽  
Thermodynamic Model ◽  
Thermal Effects ◽  
Computational Simulation ◽  
Thermal Response ◽  
Cardiac Response ◽  
The Finite Element Method ◽  
Thermal Distribution ◽  
Open Chest

In this work, the temperature distribution of the heart in an open chest surgery scenario is studied. It is also evaluated the cardiac thermal effects of the injection of a cooling liquid in the aorta root, which is used in infrared thermography. The finite element method was used to develop a model that predicts the temperature distribution modification in a 2-dimensional slice of the heart. This thermodynamic model allows the computational simulation of the thermal cardiac response to open chest procedures, which are required by cardiac surgery. The influence of several operating parameters (e.g., coronary flow rate, temperature) on the resulting thermal distribution is analyzed. Therefore, this analysis allows the identification of parameters that could be controlled to minimize the loss of energy, and consequently, avoiding the hazardous thermal distribution that could put the heart in danger during cardiac surgery.

On the Significance of Thermal and Deformation Effects on a Plain Journal Bearing Subjected to Severe Operating Conditions

2004 ◽  
Vol 126 (4) ◽  
pp. 819-822 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Thermal Effects ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Thermal Deformations ◽  
Performance Predictions ◽  
Accurate Performance ◽  
Global And Local ◽  
Highly Loaded

The present work analyzes the influence of global and local thermal effects and also mechanical and thermal deformations on bearing performance. Local thermal effects are important in the case of a highly loaded bearing because these effects are concentrated within a small zone of the bearing. The thermoelastohydrodynamic study, including deformations due to pressure, leads to a significant decrease in maximum pressure and a slight decrease in maximum temperature. For accurate performance predictions of bearings operating under severe conditions, numerical simulations have to take into account local thermal effects and both mechanical and thermal deformations.

Analysis of Microheat Pipes With Axial Conduction in the Solid Wall

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Yew Mun Hung ◽  
Kek-Kiong Tio
Keyword(s):  
Temperature Distribution ◽  
Heat Transport ◽  
Thermal Effects ◽  
Solid Wall ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Working Fluid ◽  
Transport Capacity ◽  
Axial Temperature ◽  
Energy Equations

A one-dimensional, steady-state model of a triangular microheat pipe (MHP) is developed, with the main purpose of investigating the thermal effects of the solid wall on the heat transport capacity of an MHP. The energy equation of the solid wall is solved analytically to obtain the axial temperature distribution, the average of which over the entire length of the MHP is simply its operating temperature. Next, the liquid phase is coupled with the solid wall by a heat transfer coefficient. Then, the continuity, momentum, and energy equations of the liquid and vapor phases are, together with the Young–Laplace equation, solved numerically to yield the heat and fluid flow characteristics of the MHP. The heat transport capacity and the associated optimal charge level of the working fluid are predicted for different operating conditions. Comparison between the models with and without a solid wall reveals that the presence of the solid wall induces a change in the phase change heat transport by the working fluid, besides facilitating axial heat conduction in the solid wall. The analysis also highlights the effects of the thickness and thermal conductivity of the solid wall on its axial temperature distribution. Finally, while the contribution of the thermal effects of the solid wall on the heat transport capacity of the MHP is usually not dominant, it is, nevertheless, not negligible either.

scholarly journals MODEL ORDER REDUCTION METHODS FOR COUPLED MACHINE TOOL MODELS

2021 ◽  
Vol 2021 (3) ◽  
pp. 4652-4659
Author(s):  
J. Vettermann ◽  
◽  
S. Sauerzapf ◽  
A. Naumann ◽  
M. Beitelschmidt ◽  
...  
Keyword(s):  
Thermal Effects ◽  
Model Order Reduction ◽  
Order Reduction ◽  
Work Piece ◽  
Model Accuracy ◽  
Model Order ◽  
Thermally Induced ◽  
Promising Strategy ◽  
Reduction Methods ◽  
Direct Contrast

Thermal effects are the most dominant source for displacements in machine tools and thus work-piece inaccuracies during the manufacturing process. A promising strategy to meet the ever-increasing accuracy requirements is the use of predictive models for, e.g., parameter and design op-timizations or online correction of the thermally induced error at the tool center point (TCP) in the pro-duction process. However, these techniques require fast but precise simulations. The need for high model accuracy is in direct contrast to the desired real-time capabilities. Model order reduction (MOR) is an attractive tool to overcome this problem. A modeling toolchain, which is tailored for the effective construction of fast and accurate models is proposed and demonstrated, emphasizing the involved MOR step.

Thermal Drift of Floated Gyroscopes

1957 ◽  
Vol 24 (4) ◽  
pp. 506-508
Author(s):  
L. E. Goodman ◽  
A. R. Robinson
Keyword(s):  
Temperature Distribution ◽  
Thermal Effects ◽  
Gravitational Force ◽  
Drift Rate ◽  
Force Convection ◽  
Thermal Drift ◽  
Plane Parallel

Abstract When a floated gyroscope is subjected to a temperature distribution which is not symmetrical about a plane parallel to the gravitational force, convection currents tend to rotate the gimbal. The rebalance torque and the free drift rate due to thermal effects are first determined for the case of an exactly centered gimbal. It is then shown that moderate gimbal eccentricity has little influence on thermal drift, and, in fact, reduces thermal rebalance torque.

Cutting Force and Friction Modelling in High Speed End-Milling

2015 ◽  
Author(s):  
Sunday J. Ojolo ◽  
Olumuwiya Agunsoye ◽  
Oluwole Adesina ◽  
Gbeminiyi M. Sobamowo
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Cutting Forces ◽  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
End Milling ◽  
Cutting Process ◽  
Machining Process ◽  
Work Piece

Temperature field in metal cutting process is one of the most important phenomena in machining process. Temperature rise in machining directly or indirectly determines other cutting parameters such as tool life, tool wear, thermal deformation, surface quality and mechanics of chip formation. The variation in temperature of a cutting tool in end milling is more complicated than any other machining operation especially in high speed machining. It is therefore very important to investigate the temperature distribution on the cutting tool–work piece interface in end milling operation. The determination of the temperature field is carried out by the analysis of heat transfer in metal cutting zone. Most studies previously carried out on the temperature distribution model analysis were based on analytical model and with the used of conventional machining that is continuous cutting in nature. The limitations discovered in the models and validated experiments include the oversimplified assumptions which affect the accuracy of the models. In metal cutting process, thermo-mechanical coupling is required and to carry out any temperature field determination successfully, there is need to address the issue of various forces acting during cutting and the frictional effect on the tool-work piece interface. Most previous studies on the temperature field either neglected the effect of friction or assumed it to be constant. The friction model at the tool-work interface and tool-chip interface in metal cutting play a vital role in influencing the modelling process and the accuracy of predicted cutting forces, stress, and temperature distribution. In this work, mechanistic model was adopted to establish the cutting forces and also a new coefficient of friction was also established. This can be used to simulate the cutting process in order to enhance the machining quality especially surface finish and monitor the wear of tool.

Finite Element Analysis of Turning Tire Active Mold Segment Using DEFORM-3D

2012 ◽  
Vol 501 ◽  
pp. 418-421
Author(s):  
Xiao Bin Li ◽  
Hai Ming Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Strain Distribution ◽  
Work Piece ◽  
Development Cost ◽  
Element Analysis ◽  
Force Transformation ◽  
Simulation Results ◽  
Deform 3D

By using DEFORM-3D to simulate the turing process of the tire active mold segment, the stress distribution, temperature distribution, strain distribution and cutting force transformation of turning tool and work-piece can be explored. The simulation results are helpful to configure the material and shape of the turning tools. Also the results play an important role in reducing development cost of the segment manufacturing technology and improving the accuracy and the lifetime of the mould segment.

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