Effect of coating thickness on thermal stresses in tungsten-coated optical fibers

2000 ◽  
Vol 87 (8) ◽  
pp. 3759-3762 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Pin-Tzu Lien ◽  
J.-L. He
Keyword(s):  
Optical Fibers ◽  
Coating Thickness ◽  
Thermal Stresses

The analyses of frictional losses and thermal stresses in a diesel engine piston coated with different thicknesses of thermal barrier films using co-simulation method

2021 ◽  
pp. 146808742110656
Author(s):  
Fatma Bayata ◽  
Cengiz Yildiz
Keyword(s):  
Diesel Engine ◽  
Coating Thickness ◽  
Thermal Stresses ◽  
Equivalent Stress ◽  
Simulation Method ◽  
Thermal Barrier ◽  
Barrier Films ◽  
Engine Piston ◽  
Frictional Performance ◽  
Artificial Neural Network Ann

This study comparatively presents the thermal and mechanical effects of different Thermal Barrier Coatings (TBCs) and their thicknesses on the performance of aluminum diesel engine piston by combining Finite Element Analyses (FEA) and Artificial Neural Network (ANN) methods. The piston structure of MWM TbRHS 518S indirect injection six-cylinder diesel engine was modeled. The clustered TBCs (NiCrAlY–Gd2Zr2O7, NiCrAlY–MgO-ZrO2, NiCrAl–Yttria Partially Stabilized Zirconia (YPSZ), and NiCrAlY–La2Zr2O7) were implemented to the related surface of aluminum alloy piston and then static, thermal, and transient structural FEA were conducted for each model. Based on both of the temperature and equivalent stress distributions, NiCrAlY–Gd2Zr2O7 coated model displayed the best performance. Additionally, the effects of top coating thicknesses of TBCs were investigated in the range of 0.1–1.0 mm with 0.1 mm increments in FEAs. The thermally effective top coating thickness was predicted as 0.95 mm for the selected TBC using ANN method. Then the effects of coating thickness on frictional performance were revealed by generating transient structural FE models and utilizing stribeck diagram. The uncoated and 0.95 mm NiCrAlY–Gd2Zr2O7 coated models were adjusted as transient and the related crank angle – dependent in-cylinder combustion pressure data was implemented. The friction force was reduced by at least 15% in NiCrAlY–Gd2Zr2O7 coated model.

Finite Element Analysis of Thermal Stress in Multi-Arc Ion Plated ZrTiN Hard Coatings

2010 ◽  
Vol 139-141 ◽  
pp. 369-373 ◽  
Author(s):  
Pei Yan ◽  
Jian Xin Deng ◽  
Hai Bing Cui ◽  
Xing Ai ◽  
Jun Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Stress ◽  
Thermal Stress ◽  
Coating Thickness ◽  
Deposition Temperature ◽  
Thermal Stresses ◽  
Hard Coatings ◽  
Element Analysis ◽  
Stress Components

The thermal stresses generated in ZrTiN coating deposited on HSS and tungsten carbide substrates are investigated by finite element analysis and calculated by mathematics model. FEM analysis provides detailed information about all stress components. The influence of deposition temperature, substrate materials, coating thickness and interlayers on the generation is analyzed. The thermal stress of coatings has a linear relationship with deposition temperature, and an inverse relationship with the coating thickness. The results of simulated thermal stress are in accordance with the analytical method. The highest shear stress found at the interface between the coating and substrate indicates that the interface is the critical location which is learned from the failure point of view. Results also show that the insertion of TiZr interlayer between the coating and substrate can reduce the stress components especially the shear stress. The interlayer thickness has a great effect on stress reduction.

Thermal stresses in metal-coated optical fibers

1998 ◽  
Vol 83 (11) ◽  
pp. 5719-5723 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Yi-Shyang Lin
Keyword(s):  
Optical Fibers ◽  
Thermal Stresses

Thermal stress analysis for coated fibers

1994 ◽  
Vol 9 (3) ◽  
pp. 789-796 ◽  
Author(s):  
M.G. Ellenburg ◽  
J.A. Hanigofsky ◽  
W.J. Lackey
Keyword(s):  
Thermal Stress ◽  
Stress Analysis ◽  
Coating Thickness ◽  
Crystallographic Orientation ◽  
Thermal Stresses ◽  
Physical Parameters ◽  
Coating System ◽  
Tensile Stresses ◽  
Coating Deposition ◽  
Fiber Coating

Thermal stresses induced during cooling from temperatures used for coating deposition were calculated for various fiber-coating systems. Systems under study include several types of carbon, alumina, and zirconia fibers. Coatings considered were TiB2, Si3N4, and SiC. Typical calculated stresses were on the order of 0 to 2 GPa. The results were used to analyze the effects of variable physical parameters such as coating thickness and crystallographic orientation on the stress levels. Each fiber-coating system was then compared using a nominal coating thickness of 5 μm in order to rank the various fiber-coating combinations. Among the results obtained, it was shown that orientation of deposited coatings usually leads to higher tensile stresses.

Thermal stresses in carbon-coated optical fibers at low temperature

1997 ◽  
Vol 12 (9) ◽  
pp. 2493-2498 ◽  
Author(s):  
Sham-Tsong Shiue ◽  
Wen-Hao Lee
Keyword(s):  
Thermal Stress ◽  
Low Temperature ◽  
Glass Fiber ◽  
Young’S Modulus ◽  
Optical Fibers ◽  
Poisson’S Ratio ◽  
Carbon Coating ◽  
Thermal Stresses ◽  
Poisson's Ratio ◽  
Carbon Coated

The thermal stresses in carbon-coated optical fibers at low temperature have been analyzed. The thermally induced lateral pressure in the glass fiber would produce microbending loss. In order to minimize such a microbending loss, the thickness, Young's modulus, and Poisson's ratio of the carbon coating should be decreased. On the other hand, the maximum thermal stress is the tangential stress in the carbon coating that occurs at the interface of the carbon coating and glass fiber. It was experimentally observed that if the maximum thermal stress is larger than the tensile strength of the carbon coating, the carbon coating will be broken along the axial direction. In order to minimize such a maximum thermal stress, the thickness of the carbon coating should be increased, but Young's modulus, thermal expansion coefficient, and Poisson's ratio of the carbon coating should be decreased. Finally, an optimal selection of the carbon coating for optical fiber is discussed.

Sign in / Sign up

Export Citation Format

Share Document