Chaotic Behavior of a Symmetric Laminate With Transient Thermal Field

2005 ◽  
Vol 128 (4) ◽  
pp. 429-438 ◽  
Author(s):  
Xiaoling He
Keyword(s):  
Thermal Field ◽  
Chaotic Behavior ◽  
Equation Of Motion ◽  
Induced Response ◽  
Nonlinear Dynamic Response ◽  
Type Method ◽  
Thermally Induced ◽  
Thermal Fields ◽  
Transient Thermal ◽  
Bifurcation Behavior

A symmetric isotropic laminate in a simply supported boundary condition is analyzed for its nonlinear dynamic response subjected to a nonuniform transient thermal field. The equation of motion of a modified Duffing type in a decoupled modal form is obtained for both orthotropic and isotropic symmetric laminate from the reduction of the governing equation of motion by using a Galerkin-type method. Thermally induced nonlinear response and thermal mechanically induced response are investigated in a multimode analysis. The influence of the transient thermal field is found to cause drastically different modal response from that due to the steady-state thermal field. Chaos is found being induced by the transient in-plane thermal field, or by both transient in-plane and transverse thermal fields. Unique bifurcation behavior is observed with different thermal frequencies. Different loading levels can cause transition between chaos and quasi-periodic oscillations.

scholarly journals Thermal Field Analysis and Simulation of an Infrared Belt Furnace Used for Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Bai Lu ◽  
Liang Zongcun ◽  
Shen Hui
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Gas Flow ◽  
Thermal Field ◽  
Field Analysis ◽  
Metal Particles ◽  
Thermal Fields ◽  
Internal Structures ◽  
Cell Firing ◽  
Transient Thermal

During solar cell firing, volatile organic compounds (VOC) and a small number of metal particles were removed using the gas flow. When the gas flow was disturbed by the thermal field of infrared belt furnace and structure, the metal particles in the discharging gas flow randomly adhered to the surface of solar cell, possibly causing contamination. Meanwhile, the gas flow also affected the thermal uniformity of the solar cell. In this paper, the heating mechanism of the solar cell caused by radiation, convection, and conduction during firing was analyzed. Afterward, four 2-dimensional (2D) models of the furnace were proposed. The transient thermal fields with different gas inlets, outlets, and internal structures were simulated. The thermal fields and the temperature of the solar cell could remain stable and uniform when the gas outlets were installed at the ends and in the middle of the furnace, with the gas inlets being distributed evenly. To verify the results, we produced four types of furnaces according to the four simulated results. The experimental results indicated that the thermal distribution of the furnace and the characteristics of the solar cells were consistent with the simulation. These experiments improved the efficiency of the solar cells while optimizing the solar cell manufacturing equipment.

A Coupled Motion of the Thermally Induced Fluid Convection and the Membrane Motion

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
Xiaoling He
Keyword(s):  
Thermal Field ◽  
Duffing Oscillator ◽  
Solid Material ◽  
Convection Flow ◽  
Thermally Induced ◽  
Flow Motion ◽  
Fluid Convection ◽  
The Difference ◽  
The Stability ◽  
Transient Thermal

The present study formulates a model for a coupled oscillation of the convective flow and the solid membrane vibration, which occurs in a 2D domain of a fluid cell. The convection flow is induced by the transient thermal field of the membrane at the bottom of the fluid. The heat conduction in the solid material also causes the membrane to vibrate. This flow motion deviates from the conventional Rayleigh–Benard problem in that a transient thermal field causes the convection flow instead of a constant temperature gradient. A numerical computation reveals the synchronized motion behaviors between the Lorenz-type oscillator for the convection flow and the Duffing oscillator for the membrane motion. The bifurcation conditions from the stability analysis of the model justify the steady-state attractor behaviors and the difference in behavior from the oscillators without coupling.

Prediction of Comprehensive Thermal Error of a Preloaded Ball Screw on a Gantry Milling Machine

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Kuo Liu ◽  
Haibo Liu ◽  
Te Li ◽  
Yongqing Wang ◽  
Mingjia Sun ◽  
...  
Keyword(s):  
Thermal Field ◽  
Thermal Characteristics ◽  
Thermal Error ◽  
Least Square Method ◽  
High Accuracy ◽  
Least Square ◽  
Ball Screw ◽  
Milling Machine ◽  
Thermal Fields ◽  
Proposed Model

The conception of the comprehensive thermal error of servo axes is given. Thermal characteristics of a preloaded ball screw on a gantry milling machine is investigated, and the error and temperature data are obtained. The comprehensive thermal error is divided into two parts: thermal expansion error ((TEE) in the stroke range) and thermal drift error ((TDE) of origin). The thermal mechanism and thermal error variation of preloaded ball screw are expounded. Based on the generation, conduction, and convection theory of heat, the thermal field models of screw caused by friction of screw-nut pairs and bearing blocks are derived. The prediction for TEE is presented based on thermal fields of multiheat sources. Besides, the factors influencing TDE are analyzed, and the model of TDE is established based on the least square method. The predicted thermal field of the screw is analyzed. The simulation and experimental results indicate that high accuracy stability can be obtained using the proposed model. Moreover, high accuracy stability can still be achieved even if the moving state of servo axis changes randomly, the screw is preloaded, and the thermal deformation process is complex. Strong robustness of the model is verified.

Thermal Analysis of Solids at High Peclet Numbers Subjected to Moving Heat Sources

1999 ◽  
Vol 121 (1) ◽  
pp. 182-186 ◽  
Author(s):  
O. Manca ◽  
B. Morrone ◽  
S. Nardini
Keyword(s):  
Thermal Field ◽  
Three Dimensional ◽  
Heat Losses ◽  
Transfer Model ◽  
Heat Sources ◽  
Moving Heat Source ◽  
Motion Direction ◽  
Thermal Fields ◽  
Diffusion Component ◽  
Conductive Thermal Field

A three-dimensional heat transfer model has been developed to obtain the conductive thermal field inside a brick-type solid under a moving heat source with different beam profiles. The problem in quasi-steady state has been approximated by neglecting the axial diffusion component; thus, for Peclet numbers greater than 5, the elliptic differential equation becomes a parabolic one along the motion direction. The dependence of the solution on the radiative and convective heat losses has been highlighted. Thermal fields are strongly dependent on different spot shapes and on the impinging jet; this situation allows control of the parameters involved in the technological process.

Nanoscale Continuous Directional Motion Driven by a Cyclic Thermal Field

2021 ◽  
pp. 1-19
Author(s):  
Yichang Chen ◽  
Jiantao Leng ◽  
Zhengrong Guo ◽  
Yingyan Zhang ◽  
Tienchong Chang
Keyword(s):  
Carbon Nanotube ◽  
Thermal Gradient ◽  
Thermal Field ◽  
Joint Actions ◽  
Thermal Fields ◽  
Heating Region ◽  
Directional Motion ◽  
Gradient Forces ◽  
Controllable Motion ◽  
Novel Devices

Abstract Directional motion plays a crucial role in various mechanical systems. Although mechanisms for nanoscale directional motion have been widely used in many aspects of nanotechnology, it remains a great challenge to generate continuous and controllable motion at the nanoscale. Herein we propose a nanoscale continuous directional motion in cyclic thermal fields by using a double-walled system which consists of an outer BN/C heterojunction nanotube and a concentric inner carbon nanotube (CNT). By manipulating the heating region of the outer BN/C heterojunction tube, the continuous motion of the inner CNT can be realized with ease. The inner CNT demonstrates three distinct movements due to the joint actions of the asymmetric thermal gradient forces and interlayer attraction forces caused by the presence of the outer BN/C heterojunction nanotube. The mechanism revealed in the present study may be useful in designing novel devices for energy conversion and directional transportation.

scholarly journals The Effects of Water Friction Loss Calculation on the Thermal Field of the Canned Motor

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 256 ◽  
Author(s):  
Yiping Lu ◽  
Azeem Mustafa ◽  
Mirza Abdullah Rehan ◽  
Samia Razzaq ◽  
Shoukat Ali ◽  
...  
Keyword(s):  
Thermal Field ◽  
Test Method ◽  
Friction Loss ◽  
Heat Sources ◽  
Thermal Fields ◽  
Flow And Heat Transfer ◽  
Transfer Equations ◽  
Volume Method ◽  
Canned Motor ◽  
Separation Test

The thermal behavior of a canned motor also depends on the losses and the cooling capability, and these losses cause an increase in the temperature of the stator winding. This paper focuses on the modeling and simulation of the thermal fields of the large canned induction motor by different calculation methods of water friction loss. The values of water friction losses are set as heat sources in the corresponding clearance of water at different positions along the duct and are calculated by the analytical method, loss separation test method, and by assuming the values that may be larger than the experimental results and at zero. Based on Finite volume method (FVM), 3D turbulent flow and heat transfer equations of the canned motor are solve numerically to obtain the temperature distributions of different parts of the motor. The analysis results of water friction loss are compared with the measurements, obtained from the total losses using the loss separation method. The results show that the magnitude of water friction loss within various parts of the motor does not affect the position of peak temperature and the tendency of the temperature distribution of windings. This paper is highly significant for the design of cooling structures of electrical machines.

Electroelastic field in sheared piezoelectric bodies with D∞ symmetry disturbed by transient thermal field

2018 ◽  
Vol 41 (10-12) ◽  
pp. 1346-1363
Author(s):  
Masayuki Ishihara ◽  
Yuhei Uesugi ◽  
Yoshihiro Ootao ◽  
Yoshitaka Kameo
Keyword(s):  
Thermal Field ◽  
Electroelastic Field ◽  
Transient Thermal

scholarly journals Transient Thermal Field Analysis in ACCC Power Lines by the Green’s Function Method

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 280
Author(s):  
Jerzy Gołębiowski ◽  
Marek Zaręba
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Field ◽  
Continuity Condition ◽  
Field Analysis ◽  
Parabolic Differential Equations ◽  
Steady State Current ◽  
Core Line ◽  
Transient Thermal

The paper investigates the dynamics of the thermal field of the ACCC (aluminum conductor composite core) line. The system was heated by solar radiation and current flow. Conductor cooling was modeled using the total heat transfer coefficient as the sum of convective and radiative components. The temperature increase generated by the current is described by a system of parabolic differential equations with an appropriate set of boundary, initial and continuity condition. The mentioned boundary-initial problem was solved by a modified Green’s method, adapted to the layered structure of the system. For this purpose, Green’s functions, as the kernels of integral operators inverse to differential ones, were determined. Aluminum resistivity and heat transfer coefficient change significantly with temperature. For this reason, the solution to the problem is presented in the form of a lower and upper estimation of the heating curve and local time constant. A steady-state current rating was also determined. The results are presented graphically and verified by other methods (power balance and finite element). The physical interpretation of the presented solution is also given.

Thermal Effects During Infrared Solder Reflow—Part I: Heat Transfer Mechanisms

1992 ◽  
Vol 114 (1) ◽  
pp. 41-47 ◽  
Author(s):  
N. J. Fernandes ◽  
T. L. Bergman ◽  
G. Y. Masada
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Convective Heating ◽  
Transfer Coefficients ◽  
Thermally Induced ◽  
Heat Transfer Coefficients ◽  
Model Predictions ◽  
Transient Thermal ◽  
Transfer Mechanisms ◽  
Simple Numerical Model

An experimental study has been conducted to reveal the relevant heat transfer mechanisms which exist within an infrared reflow oven. Simulated card assemblies are used and their transient thermal responses, induced by combined radiative and convective heating, are measured. A simple numerical model is developed with which relevant heat transfer mechanisms are identified and quantified. The study shows that radiative and mixed convective heat transfer processes induce a variety of system thermal responses. Model predictions, which incorporate measured forced convection heat transfer coefficients and accurate descriptions of surface-to-surface radiative exchange, are in excellent agreement with experimental data for cases where the thermally induced buoyancy forces within the oven air are relatively small. The results of the experimental and analytical study provide guidelines for the development of more sophisticated models of the infrared reflow process.

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