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Tasdiq Ahmed - One of the best experts on this subject based on the ideXlab platform.

  • Chronological evaluation of Interfacial Damage in TBC due to thermal cycling
    Journal of Materials Science, 1999
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed, R. L. Thomas
    Abstract:

    A two layer electron beam-physical vapor deposited (EV-PVD) thermal barrier coating (TBC) on a single crystal superalloy (René N5) substrate was characterized prior to and after thermal cycling at 2, 18, 25, 44, 50, 75, 100, 110, 150, and 175 cycles in between 200 C-1177 C. Optical microscopy, scanning electron microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage. Pt-Al was used as bond coat and 8 wt % YSZ was used as outer top layer. Interfacial cracking was observed even at two thermal cycles. Thermally grown oxide (TGO) layer increased with the number of thermal cycles. After numerous cycles over 100, Interfacial separation was observed to be higher at the middle than at the edges of the sample. This observation is consistent with buckling induced delamination—a possible mechanism for spallation.

  • Chronological evaluation of Interfacial Damage in TBC due to thermal cycling
    Journal of Materials Science, 1999
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed, R. L. Thomas
    Abstract:

    A two layer electron beam-physical vapor deposited (EV-PVD) thermal barrier coating (TBC) on a single crystal superalloy (Rene N5) substrate was characterized prior to and after thermal cycling at 2, 18, 25, 44, 50, 75, 100, 110, 150, and 175 cycles in between 200 C-1177 C. Optical microscopy, scanning electron microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage. Pt-Al was used as bond coat and 8 wt % YSZ was used as outer top layer. Interfacial cracking was observed even at two thermal cycles. Thermally grown oxide (TGO) layer increased with the number of thermal cycles. After numerous cycles over 100, Interfacial separation was observed to be higher at the middle than at the edges of the sample. This observation is consistent with buckling induced delamination—a possible mechanism for spallation.

  • Interfacial Damage in EB-PVD thermal barrier coatings due to thermal cycling
    Materials Science and Engineering: A, 1997
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed
    Abstract:

    Optical microscopy, acoustic microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage in a thermal barrier coated single crystal superalloy subjected to thermal cycling. The thermal barrier coating (TBC) was applied to the superalloy using electron beam physical vapor deposition (EB-PVD) technique. The EB-PVD system seems to be stable at least up to the temperature of 1000°C for 300 cycles. Thermal expansion mismatch and oxidation between the bond coat and ceramic layer leads to separation at the interface which contributes to overall delamination and spallation. Experimental results suggest that buckling induced delamination is a possible mechanism for spallation.

Z. A. Chaudhury - One of the best experts on this subject based on the ideXlab platform.

  • Chronological evaluation of Interfacial Damage in TBC due to thermal cycling
    Journal of Materials Science, 1999
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed, R. L. Thomas
    Abstract:

    A two layer electron beam-physical vapor deposited (EV-PVD) thermal barrier coating (TBC) on a single crystal superalloy (René N5) substrate was characterized prior to and after thermal cycling at 2, 18, 25, 44, 50, 75, 100, 110, 150, and 175 cycles in between 200 C-1177 C. Optical microscopy, scanning electron microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage. Pt-Al was used as bond coat and 8 wt % YSZ was used as outer top layer. Interfacial cracking was observed even at two thermal cycles. Thermally grown oxide (TGO) layer increased with the number of thermal cycles. After numerous cycles over 100, Interfacial separation was observed to be higher at the middle than at the edges of the sample. This observation is consistent with buckling induced delamination—a possible mechanism for spallation.

  • Chronological evaluation of Interfacial Damage in TBC due to thermal cycling
    Journal of Materials Science, 1999
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed, R. L. Thomas
    Abstract:

    A two layer electron beam-physical vapor deposited (EV-PVD) thermal barrier coating (TBC) on a single crystal superalloy (Rene N5) substrate was characterized prior to and after thermal cycling at 2, 18, 25, 44, 50, 75, 100, 110, 150, and 175 cycles in between 200 C-1177 C. Optical microscopy, scanning electron microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage. Pt-Al was used as bond coat and 8 wt % YSZ was used as outer top layer. Interfacial cracking was observed even at two thermal cycles. Thermally grown oxide (TGO) layer increased with the number of thermal cycles. After numerous cycles over 100, Interfacial separation was observed to be higher at the middle than at the edges of the sample. This observation is consistent with buckling induced delamination—a possible mechanism for spallation.

  • Interfacial Damage in EB-PVD thermal barrier coatings due to thermal cycling
    Materials Science and Engineering: A, 1997
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed
    Abstract:

    Optical microscopy, acoustic microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage in a thermal barrier coated single crystal superalloy subjected to thermal cycling. The thermal barrier coating (TBC) was applied to the superalloy using electron beam physical vapor deposition (EB-PVD) technique. The EB-PVD system seems to be stable at least up to the temperature of 1000°C for 300 cycles. Thermal expansion mismatch and oxidation between the bond coat and ceramic layer leads to separation at the interface which contributes to overall delamination and spallation. Experimental results suggest that buckling induced delamination is a possible mechanism for spallation.

Yiqi Mao - One of the best experts on this subject based on the ideXlab platform.

  • Interfacial Damage analysis of shallow spherical shell with FGM coating under low velocity impact
    International Journal of Mechanical Sciences, 2013
    Co-Authors: Yiqi Mao, Daining Fang
    Abstract:

    Abstract Interfacial Damage would seriously reduce the structures' property, especially structures with coating when under dynamic loading. In this paper, the Interfacial Damage of shallow spherical shell with functionally graded material (FGM) coating subjected to low velocity impact is studied. An Interfacial Damage analytical model is established based on the continuum theory-based Interfacial Damage constitutive relations. The A.E. Giannakopoulos's 2-D functionally graded material (FGM) contact model is applied to predict contact force. Motion equations for shallow spherical shell substrate and FGM coating are obtained by Reissner variation, respectively, and the dynamic analytical model is established by using Interfacial connection relations to relate the motion equations for FGM coating and those for elastic shallow spherical substrate. The orthogonal collocation point method, the Newmark method and iterative method are used synthetically to solve the whole question. In numerical examples, the dynamic response of shallow spherical shell with FGM coating and contact force are obtained, and the effects of material and geometrical parameters of FGM coating on Interfacial Damage and contact force have been discussed.

  • THE ANALYSIS OF INTERLAMINAR STRESSES FOR COMPOSITE LAMINATED SHALLOW SHELLS WITH Interfacial Damage
    Acta Mechanica Solida Sinica, 2011
    Co-Authors: Yiqi Mao
    Abstract:

    Based on the general six-degrees-of-freedom plate theory towards the accurate stress analysis and nonlinear theory of shallow shells, considering the Damage effect of the interlaminar interface and using the variation principle, the three-dimensional non-linear equilibrium differential equations of the laminated shallow shells with Interfacial Damage are derived. Then, considering a simply supported laminated shallow shell with Damage and under normal load, an analytical solution is presented by using finite difference method to obtain the interlaminar stresses. Numerical results show, the stiffness of the shell is weakened, greater absolute values of displacements as well as smaller interlaminar stresses are obtained by Interfacial Damage. When the Interfacial Damage is further increased, delamination occurs obviously under normal pulling load and pure shear slip occurs under normal pressure load. The portion of the load undertaken by the two sides of the interface is more different. Different mechanical behaviors are shown in both sides of the interface, and the discontinuation of stresses and displacements takes place in the interface.

  • nonlinear static dynamic analysis for elasto plastic laminated plates with Interfacial Damage evolution
    Composite Structures, 2010
    Co-Authors: Yanping Tian, Yiqi Mao
    Abstract:

    Abstract A new analysis model, which includes the effects of Interfacial Damage, geometrical nonlinearity and material nonlinearity, is presented for elasto-plastic laminated plates. Based on the model, the nonlinear equilibrium differential equations for elasto-plastic laminated plates with Interfacial Damage are established. The finite difference method and iteration method are adopted to solve these equations. The nonlinear static and dynamic behaviors for the elasto-plastic laminated plates under the action of transverse loads are analyzed. Effects of Interfacial Damage on the stress and displacement distribution and nonlinear dynamic response are discussed in the numerical examples together with the comparison of nonlinear mechanical behaviors between the elastic and elasto-plastic laminated plates. Numerical results show that both the Interfacial Damage and plastic deformation put obvious influence on the mechanical properties of structures.

Yang Chen - One of the best experts on this subject based on the ideXlab platform.

  • Thermal postbuckling analysis of fiber–metal laminated plates including Interfacial Damage
    Composites Part B: Engineering, 2014
    Co-Authors: Jun Zhong, Yang Chen
    Abstract:

    Abstract Considering the effects of Interfacial Damage, geometric nonlinearity and transverse shear deformation, thermal postbuckling of fiber–metal laminated plates including Interfacial Damage is analyzed in detail. Firstly, the Heaviside step function and higher order shear deformation functions are introduced into displacement field so that the Damage degree can be characterized. Then, the shape functions can be determined by using the stress continuity conditions between interfaces and the stress boundaries on surfaces. By using the generalized variational principle, the thermal postbuckling equilibrium equations of fiber–metal laminated plates including Interfacial Damage are established. Finally, the thermal postbuckling problem is solved by adopting finite difference method and iteration method. In numerical examples, the effects of Interfacial Damage, width-to-thickness ratio and thermal load on the thermal postbuckling of fiber–metal laminated plates including Interfacial Damage are investigated.

  • thermal postbuckling analysis of fiber metal laminated plates including Interfacial Damage
    Composites Part B-engineering, 2014
    Co-Authors: Jun Zhong, Yang Chen
    Abstract:

    Abstract Considering the effects of Interfacial Damage, geometric nonlinearity and transverse shear deformation, thermal postbuckling of fiber–metal laminated plates including Interfacial Damage is analyzed in detail. Firstly, the Heaviside step function and higher order shear deformation functions are introduced into displacement field so that the Damage degree can be characterized. Then, the shape functions can be determined by using the stress continuity conditions between interfaces and the stress boundaries on surfaces. By using the generalized variational principle, the thermal postbuckling equilibrium equations of fiber–metal laminated plates including Interfacial Damage are established. Finally, the thermal postbuckling problem is solved by adopting finite difference method and iteration method. In numerical examples, the effects of Interfacial Damage, width-to-thickness ratio and thermal load on the thermal postbuckling of fiber–metal laminated plates including Interfacial Damage are investigated.

R. L. Thomas - One of the best experts on this subject based on the ideXlab platform.

  • Chronological evaluation of Interfacial Damage in TBC due to thermal cycling
    Journal of Materials Science, 1999
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed, R. L. Thomas
    Abstract:

    A two layer electron beam-physical vapor deposited (EV-PVD) thermal barrier coating (TBC) on a single crystal superalloy (René N5) substrate was characterized prior to and after thermal cycling at 2, 18, 25, 44, 50, 75, 100, 110, 150, and 175 cycles in between 200 C-1177 C. Optical microscopy, scanning electron microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage. Pt-Al was used as bond coat and 8 wt % YSZ was used as outer top layer. Interfacial cracking was observed even at two thermal cycles. Thermally grown oxide (TGO) layer increased with the number of thermal cycles. After numerous cycles over 100, Interfacial separation was observed to be higher at the middle than at the edges of the sample. This observation is consistent with buckling induced delamination—a possible mechanism for spallation.

  • Chronological evaluation of Interfacial Damage in TBC due to thermal cycling
    Journal of Materials Science, 1999
    Co-Authors: Z. A. Chaudhury, Golam Newaz, S. Q. Nusier, Tasdiq Ahmed, R. L. Thomas
    Abstract:

    A two layer electron beam-physical vapor deposited (EV-PVD) thermal barrier coating (TBC) on a single crystal superalloy (Rene N5) substrate was characterized prior to and after thermal cycling at 2, 18, 25, 44, 50, 75, 100, 110, 150, and 175 cycles in between 200 C-1177 C. Optical microscopy, scanning electron microscopy, and thermal wave imaging techniques were used to characterize the Interfacial Damage. Pt-Al was used as bond coat and 8 wt % YSZ was used as outer top layer. Interfacial cracking was observed even at two thermal cycles. Thermally grown oxide (TGO) layer increased with the number of thermal cycles. After numerous cycles over 100, Interfacial separation was observed to be higher at the middle than at the edges of the sample. This observation is consistent with buckling induced delamination—a possible mechanism for spallation.