THREE-DIMENSIONAL THERMAL DEFORMATION AND THERMAL STRESS IN WORKPIECES UNDER SURFACE GRINDING

1985 ◽  
Vol 8 (3) ◽  
pp. 305-318 ◽  
Author(s):  
Tadao Kagiwada ◽  
Tadahiko Kanauchi
Keyword(s):  
Thermal Stress ◽  
Thermal Deformation ◽  
Three Dimensional ◽  
Surface Grinding

scholarly journals Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1252
Author(s):  
Junqing Li ◽  
Luo Wang
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Thermal Deformation ◽  
Short Circuit ◽  
Three Dimensional ◽  
Static Field ◽  
Heat Transfer Theory ◽  
Circuit Fault Diagnosis ◽  
Rotor Winding ◽  
Magnetic Poles

Rotor winding inter-turn short circuit a common fault in hydro-generators. This fault would change the temperature, stress, and other thermal fields of a rotor and threaten the safe operation of the generator. In this paper, the Three Gorges hydro-generator is taken as an example. Mathematical models of three-dimensional temperature field and thermal stress field of rotor magnetic poles are established based on heat transfer theory and solved by finite element method. The temperature field, thermal deformation, and thermal stress distribution of magnetic poles in rotor winding inter-turn short circuit are calculated. On the basis of the calculation, the effects of the different turn numbers and positions of short circuit on the temperature, thermal deformation, and thermal stress of rotor magnetic poles are further studied. It is concluded that the thermal stress of the winding adjacent to the shorted turn would decrease, the thermal stress of the winding farther away from the shorted winding would increase, and so on. The results of this paper can provide references for inter-turn short circuit fault diagnosis and lay a foundation for the further studies of related faults.

Thermomechanical Analytical 3D Thermal/Stress Estimation Sidewall Grinding Model

1999 ◽  
Vol 121 (3) ◽  
pp. 378-384 ◽  
Author(s):  
Ya Yun Li ◽  
Jongwon Kim ◽  
Yunquan Sun ◽  
Yanhua Yang
Keyword(s):  
Thermal Stress ◽  
Temperature Distribution ◽  
Thermal Model ◽  
Three Dimensional ◽  
Surface Grinding ◽  
Stress Model ◽  
Creep Feed ◽  
Conventional Grinding ◽  
External Cylindrical Grinding ◽  
Sidewall Surface

A general three-dimensional thermal/stress grinding model, based on thermal and elastic/plastic classical analytical solutions, has been developed in this paper. The thermal model can predict the temperature distribution of surface and cylindrical external/internal creep-feed or conventional grinding for vertical or inclined sidewall surface grinding. This paper deals with a grinding burn problem that is widespread in the aerospace and automotive industries. The thermal model is compared with sidewall surface grinding experiments. The comparison of the temperature distribution results is expected. The general stress model has been developed, which combines both spherical and cylindrical coordinates. In addition, the 3D thermal/stress model is compared with four cases of external cylindrical grinding experiments. The residual stresses agree reasonably.

scholarly journals Modeling and Measurement of Thermal Effect in a Flashlamp-Pumped Direct-Liquid-Cooled Split-Disk Nd:LuAG Ceramic Laser Amplifier

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Shengzhe Ji ◽  
Wenfa Huang ◽  
Tao Feng ◽  
Long Pan ◽  
Jiangfeng Wang ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Thermal Effects ◽  
Thermal Deformation ◽  
High Energy ◽  
Gain Medium ◽  
Wavefront Aberration ◽  
Experimental Measurements ◽  
Laser Amplifier ◽  
Design And Optimization ◽  
Ceramic Laser

In this paper, a model to predict the thermal effects in a flashlamp-pumped direct-liquid-cooled split-disk Nd:LuAG ceramic laser amplifier has been presented. In addition to pumping distribution, the model calculates thermal-induced wavefront aberration as a function of temperature, thermal stress and thermal deformation in the gain medium. Experimental measurements are carried out to assess the accuracy of the model. We expect that this study will assist in the design and optimization of high-energy lasers operated at repetition rate.

Minimization of the Local Residual Stress in 3D Flip Chip Structures by Optimizing the Mechanical Properties of Electroplated Materials and the Alignment Structure of TSVs and Fine Bumps

2011 ◽  
Author(s):  
Kohta Nakahira ◽  
Hironori Tago ◽  
Fumiaki Endo ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Thermal Deformation ◽  
Flip Chip ◽  
Flexural Rigidity ◽  
Three Dimensional ◽  
Strain Gauges ◽  
Copper Interconnection ◽  
Induced Stress ◽  
Alignment Structure

Since the thickness of the stacked silicon chips in 3D integration has been thinned to less than 100 μm, the local thermal deformation of the chips has increased drastically because of the decrease of the flexural rigidity of the thinned chips. The clear periodic thermal deformation and thus, the thermal residual stress distribution appears in the stacked chips due to the periodic alignment of metallic bumps, and they deteriorate the reliability of products. In this paper, the dominant structural factors of the local residual stress in a silicon chip are discussed quantitatively based on the results of a three-dimensional finite element analysis and the measurement of the local residual stress in a chip using stress sensor chips. The piezoresistive strain gauges were embedded in the sensor chips. The length of each gauge was 2 μm, and an unit cell consisted of 4 gauges with different crystallographic directions. This alignment of strain gauges enables to measure the tensor component of three-dimensional stress fields separately. Test flip chip substrates were made by silicon chip on which the area-arrayed tin/copper bumps were electroplated. The width of a bump was fixed at 200 μm, and the bump pitch was varied from 400 μm to 1000 μm. The thickness of the copper layer was about 40 μm and that of tin layer was about 10 μm. This tin layer was used for the rigid joint formation by alloying with copper interconnection formed on a stress sensing chip. The measured amplitude of the residual stress increased from about 30 MPa to 250 MPa depending on the combination of materials such as bump, underfill, and interconnections. It was confirmed that both the material constant of underfill and the alignment structure of fine bumps are the dominant factors of the local deformation and stress of a silicon chip mounted on area-arrayed metallic bumps. It was also confirmed experimentally that both the hound’s-tooth alignment between a TSV (Through Silicon Via) and a bump and control of mechanical properties of electroplated copper thin films used for the TSV and bump is indispensable in order to minimize the packaging-induced stress in the three-dimensionally mounted chips. This test chip is very effective for evaluating the packaging-process induced stress in 3D stacked chips quantitatively.

Steady-State Formulation for Stress and Distortion of Welds

1994 ◽  
Vol 116 (4) ◽  
pp. 467-474 ◽  
Author(s):  
M. Gu ◽  
J. A. Goldak
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Three Dimensional ◽  
Significant Gain ◽  
Free Boundaries ◽  
Flow Lines ◽  
Eulerian Formulation ◽  
Noticeable Reduction ◽  
Computing Speed ◽  
Lagrangian Frame

A steady state formulation has been developed for thermal stress analysis. It uses features from both the Lagrangian formulation and the Eulerian formulation. The mesh sits on an Eulerian frame but deforms as if in the Lagrangian frame. Therefore, it is suitable for steady state problems with free boundaries. History dependent parameters are integrated along flow lines. A significant gain in computing speed and/or spatial resolution over transient analyses has been achieved together with a noticeable reduction for memory requirements. Numerical results are given for a three-dimensional analysis of edge weld.

scholarly journals Thermal-mechanical behavior of sandwich panels with closed-cell foam core under intensive laser irradiation

2014 ◽  
Vol 18 (5) ◽  
pp. 1607-1611 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Wei-Dong Song ◽  
Hui-Ping Tang ◽  
Zhi-Hua Wang ◽  
Long-Mao Zhao
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stress ◽  
Specific Heat ◽  
Laser Irradiation ◽  
Thermal Deformation ◽  
Sandwich Panels ◽  
Protective Layer ◽  
Foam Core ◽  
Closed Cell ◽  
Analysis Models

Temperature field and thermal deformation of sandwich panels with closed-cell aluminum alloy foam core and heat-protective layer, which are subjected to Gaussian laser beam intensively irradiating, are investigated numerically. In transient heat analysis models, the influence of thermal conductivity, specific heat, and thickness of heat-protective layer on the temperature rise of the sandwich panels is calculated. In stress analysis models, a sequence coupled numerical method is utilized to simulate the thermal stress and deformation of sandwich panels induced by thermal expansion. Simulation results indicate that the temperature at center of sandwich panel increases firstly and then drops gradually with the increase of thermal conductivity of heat-protective layer after laser irradiation, and the critical thermal conductivity is obtained, while it decreases with the increase of specific heat and thickness of heat-protective layer. The thermal stress verifies the ?Cyclo-hoop effect?, i. e. radial stress is compression stress in ?hot zone? and tension stress in ?cold zone?. The max thermal deformation of sandwich panels slightly increases with the increase of thickness of heat-protective layer for given specific heat and thermal conductivity.

THERMAL EXPANSION OF PHASE-CHANGE RANDOM ACCESS MEMORY CELLS

2008 ◽  
Vol 1072 ◽  
Author(s):  
Jianming Li ◽  
L.P. Shi ◽  
H.X. Yang ◽  
K.G. Lim ◽  
X.S. Miao ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Phase Change ◽  
Electrical Power ◽  
Thermal Strain ◽  
Three Dimensional ◽  
Amorphous State ◽  
Random Access ◽  
Random Access Memory ◽  
Access Memory ◽  
Three Dimensional Finite Element

ABSTRACTThree-dimensional finite element method (FEM) is used to solve the thermal strain-stress fields of phase-change random access memory (PCRAM) cells. Simulation results show that thermal stress concentrates at the interfaces between electrodes and phase change layer and it is significantly larger than that within the phase change layer. It has been found that the peak thermal stress is linearly related to the voltage of electrical pulse in the reset process but once amorphous state is produced in the cell, a nonlinear relationship between thermal stress and electrical power exists. This paper reported the change of thermal stress during set process. It was found that the stress decreases significantly due to the amorphous active region during set processes.

Thermal–stress analysis of a three-dimensional end-plate steel joint

2012 ◽  
Vol 29 ◽  
pp. 619-626 ◽  
Author(s):  
Andreas Kalogeropoulos ◽  
Georgios A. Drosopoulos ◽  
Georgios E. Stavroulakis
Keyword(s):  
Thermal Stress ◽  
Stress Analysis ◽  
Three Dimensional ◽  
Plate Steel ◽  
Thermal Stress Analysis ◽  
Steel Joint ◽  
End Plate
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