scholarly journals Evaluation Method for Inelastic Constitutive Equation of Thermal Sprayed Ceramic Coating by Bending Strain of Coating System

2021 ◽  
Vol 70 (10) ◽  
pp. 758-765
Author(s):  
Noriyuki OKUBO ◽  
Hiroyuki WAKI ◽  
Kanta ADACHI
Author(s):  
J.H. Mohmmed

Purpose: A new high thermal stability single layer glass–ceramic coating system designing for applied on various grade of steel alloy has been developed in this work. Design/methodology/approach: The thermal shock resistance, thermal conductivity and thermal expansion of the coating system were evaluated by using suitable standard tests. Some crystalline agents (Lithium oxide Li2O, Titanium oxide TiO2, Zircon ZrSiO4 and Feldspar CaO∙Al2O3∙2SiO2) were add at constant ratio 6% to coating system to evaluate their effects on the resultant coatings. Findings: The results indicate the suitability of these coatings for protection of metal substrate. Also the results show that the properties of resultant coating were hardly affected by composition and concentration of crystalline agent. Research limitations/implications: Coating with lithium oxide has the lowest thermal expansion, which means the highest thermal shock resistance. While, values of thermal conductivity were too close for all types of coating. Originality/value: Generally, the resultant coating properties have been enhanced in all cases; this is associated with the introduce the crystalline agent which lead to the formation of a complex network of crystalline phases.


Author(s):  
Jose J. Loza ◽  
Komal Laul ◽  
Mickey Carroll ◽  
Bobby Pike

Abstract Acquisition of a new LVPS and APS coating system at Delta Air Lines necessitated optimization of the coating parameters on both systems; especially for application of bond coat (LVPS) and top coat (APS) for a TBC coating system. To expedite the coating optimization; it was determined that a design of experiments (DOE) approach would best enable the establishment of the operating window for the two systems. Samples prepared were primarily evaluated for their performance while exposed to a cyclic oxidation cycle. Samples were also evaluated for the microstructure and composition using energy dispersive spectroscopy (EDS) analysis. Samples from the ceramic coating DOE were also evaluated for their erosion characteristics. Results indicate a low correlation between the individual bond coat parameters evaluated to the furnace cycle life. However; the top coat spray parameters were found to have a greater correlation to furnace cycle life and erosion performance.


Author(s):  
Masanori Kikuchi ◽  
Kazuhiro Suga ◽  
Shota Kawasaki

Interaction effect of multiple flaws on ductile fracture is studied numerically by using Gurson’s constitutive equation. Based on experiments, 2 parallel cracks problems and 3 parallel cracks problems are simulated. In some problems, crack coalescence does not occur, and it occurs in other cases. In all cases, ductile fracture processes are obtained, and results are compared with experimental ones. Fracture pattern and load-displacement curves agree well with experiments. It is shown that void growth term is dominant for the coalescence of cracks. Slanted crack problem and non-uniform length crack problem are simulated and evaluation method of multiple cracks problem is discussed.


2019 ◽  
Vol 17 (3) ◽  
pp. 998-1009 ◽  
Author(s):  
Ivana Petríková ◽  
Milan Parchovianský ◽  
Peter Švančárek ◽  
Mateus Lenz Leite ◽  
Günter Motz ◽  
...  

2019 ◽  
Vol 827 ◽  
pp. 343-348
Author(s):  
Ryuta Nakajima ◽  
Hiroaki Katori ◽  
Masayuki Arai ◽  
Kiyohiro Ito

TBCs (Thermal Barrier Coatings) is deposited on gas turbine blades to protect the substrate from a combustion gas flow. One of the serious problems occurred in gas turbine is TBC delamination which is caused by startup, steady and stop operation in service. TBC delamination results from subjecting to both cyclic thermal stress and evolution of internal stress due to thermally grown oxide (TGO). In this study, the finite element code which can simulate thermal and internal stress fields generated in TBC was developed. The developed code involves the follows: inelastic constitutive equation for ceramic coating, bilinear-type constitutive equation for bond coating and Chaboche-type inelastic constitutive equation for the substrate, and mass transfer equation in consideration of oxygen diffusion and chemical reaction with aluminum. Thermal cycling simulation was conducted using the developed code. It was confirmed that maximum stress and its location in the ceramic coating/bond coating interface were matched with the associated experimental results.


2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Kazuhiro Suga ◽  
Masanori Kikuchi ◽  
Shota Kawasaki

The effect of the interaction of multiple flaws on ductile fracture is studied numerically by Gurson’s constitutive equation. Based on experimental results, two parallel flaw and three parallel flaw problems are simulated. Flaw coalescence does not occur in some problems but does occur in other cases. In all cases, ductile fracture processes are obtained, and the results are compared with the experimental results. The fracture pattern and load-displacement curves agree well with the experimental results. The void growth term is found to be dominant for the coalescence of flaws. The slant flaw problem and the nonuniform length flaw problem are simulated and an evaluation method for the multiple flaws problem is discussed.


2012 ◽  
Vol 61 (10) ◽  
pp. 831-836
Author(s):  
Takuji YAMADA ◽  
Yoichi TSUKUDA ◽  
Takashi YAMAMOTO ◽  
Minoru KUNIEDA ◽  
Toyoaki MIYAGAWA

Author(s):  
Masanori Ando ◽  
Taiji Tezuka ◽  
Toshio Nakamura ◽  
Tomohiro Okawa ◽  
Yasuhiro Enuma ◽  
...  

In Fast Breeder Reactor, dominant stresses in the piping system are secondary, which are induced by constraint of the thermal expansion of components and pipes. Therefore, the structural design rule should essentially prevent the buckling caused by displacement controlled loads. In this study, the evaluation method of the buckling criterion of cantilever type pipes subjected to lateral displacements is proposed. We define the criterion of the deformation controlled buckling based on bending strain at local buckling portion. Then finite element analysis (FEA) is performed for estimating the displacement and bending strain at local buckling portion during the displacement controlled buckling. Those defined criterion and results of FEA are availed to investigate the evaluation method of the displacement controlled buckling criterion. In those FEA, material properties of Mod.9Cr-1Mo steel are applied, because the material is a candidate for primary and secondary heat transport system components of JSFR (Japan Sodium cooled Fast Reactor), and those of 316FR (type 316 stainless steel modified for FR) are also used to compare the FEA results of Mod.9Cr-1Mo steel. Results of FEA suggest that buckling behaviors strongly depend on the distribution of bending moment and strain hardening behavior of the material. Therefore, those features must be considered in construction of the evaluation method of displacement controlled buckling. To consider the distribution of bending moment, two indexes are defined. One indicates nonlinear bending displacement of a straight pipe. The other indicates the configuration of the pipe and material properties. Relationship between those indexes, which including criterion of displacement controlled buckling, is formulated by the enveloped line considering the effect of the strain hardening behavior of the material. As a result, an equation which represents the criterion for displacement controlled buckling of cantilever type pipes was proposed. This equation consists of two indexes as mentioned above, and can estimate criterion of displacement controlled buckling by material properties and pipe configuration. The proposed equation can be applied to the pipes made of Mod.9Cr-1Mo steel and 316FR.


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