The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

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

  • investigation of long term thermal aging induced damage in oxide oxide Ceramic Matrix Composites
    Journal of The European Ceramic Society, 2020
    Co-Authors: Zhengmao Yang, Junjie Yang
    Abstract:

    Abstract Long-term thermal aging is a typical factor affecting the thermo-mechanical fatigue life for hot-end components in the gas turbine. The present work focuses on the development of thermal aging-induced damage in 2-D woven oxide/oxide Ceramic Matrix Composites from micro-mechanism and macroscopic mechanical performance. The porosity evolution and mechanical performance after long-term thermal aging were characterized through mercury intrusion measurements and uniaxial compressive tests, respectively. The results show that the decrease of micro-porosity directly reflects the irreversible evolution of material microstructure in the thermal aging process, and the decrease of compressive strength after aging is the macroscopic reflection of the microstructure variation. The porosity increment of Matrix was thus used to characterize the thermal aging-induced damage, establishing a unique analysis model between the increment of micro-porosity under thermal aging and the corresponding degradation of material compressive strength. The experimental results are in good agreement with the established model.

  • effects of thermal aging on the cyclic thermal shock behavior of oxide oxide Ceramic Matrix Composites
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2020
    Co-Authors: Zhengmao Yang
    Abstract:

    Abstracts A particular emphasis is placed on the thermal aged oxide/oxide Ceramic Matrix Composites under cyclic thermal shocks, which exhibit hierarchical internal structures spanning multiple volume/scales. The present work focuses on establishing thermo-mechanical loading conditions-structure-property linkages for the thermal aged oxide/oxide Ceramic Matrix Composites under cyclic thermal shocks. Firstly, the Matrix micro-cracks and delamination were identified by SEM observation, and the compressive mechanical behaviors were studied after different cyclic thermal shock numbers. The thermal aging process resulted in apparent changes in thermal shock resistance of materials. Considering the material deterioration induced by the thermal aging process, aging-related factor was introduced to predict the compress behaviors of the thermal aged oxide/oxide Ceramic Matrix Composites under cyclic thermal shocks. The correlation between porosity and strain energy release rate was also constructed, which provided an excellent agreement with the experiments.

  • micro porosity as damage indicator for characterizing cyclic thermal shock induced anisotropic damage in oxide oxide Ceramic Matrix Composites
    Engineering Fracture Mechanics, 2019
    Co-Authors: Zhengmao Yang, Hui Liu, Huang Yuan
    Abstract:

    Abstract Ceramic Matrix Composites display complex mechanical behavior under thermo-mechanical loading conditions. The present work focuses on micro-structural evolution and resultant macroscopic property representation of the Composites after cyclic thermal shocks. Micro-structural investigation reveals that variations of the hierarchical porosity in the Matrix characterize the collective behavior of micro-structural evolution in the material. Cyclic thermal shocks induce thermo-mechanical damage and lead to increasing Matrix porosity. Material damage development is driven by elastic strain energy density which is related to the Matrix porosity increment. Experiments confirm that the anisotropic damage can be represented by the porosity increment accurately. The porosity provides a meaningful model for the thermal shock damage evolution in the anisotropic Composites.

  • representation of micro structural evolution and thermo mechanical damage in thermal shocked oxide oxide Ceramic Matrix Composites
    International Journal of Fatigue, 2019
    Co-Authors: Zhengmao Yang, Huang Yuan, Bernd Markert
    Abstract:

    Abstract The oxide/oxide Ceramic Matrix Composites display complex mechanical behavior under thermo-mechanical loading conditions. The present work focuses on micro-structural evolution and resultant macroscopic properties during cyclic thermal shocks. Micro-structural investigation reveals that variations of nano-, micro- and macro-pores in the Matrix characterize collective behavior of micro-structural evolution in the material. Material damage development is characterized by micro-cracking in the Matrix and can be described by the Matrix porosity increment. The present investigation confirms the unique correlation between the porosity and the micro-structural degradation evolution of the material under different loading conditions.

Zhai Hongxiang - One of the best experts on this subject based on the ideXlab platform.

  • the effect of whisker orientation in sic whisker reinforced si3n4 Ceramic Matrix Composites
    Journal of The European Ceramic Society, 1999
    Co-Authors: Wang Changan, Huang Yong, Zhai Hongxiang
    Abstract:

    Abstract Si 3 N 4 Ceramic Matrix Composites reinforced by nearly unidirectionally aligned SiC whiskers have been prepared by extrusion and hot pressing. Unlike the case in traditional Si 3 N 4 Ceramic Matrix Composites reinforced by random SiC whiskers, the mechanical properties of the Composites exhibit a significant dependence on whisker orientation. In the direction of whisker alignment for SiC(w)/Si 3 N 4 Composites, increments in bending strength and fracture toughness of 200 MPa and 3 MPa·m 1/2 are obtained respectively, compared to the values in the direction perpendicular to whisker alignment. Based on microscopic fractographic observation and micromechanics analyses, the effects of whisker orientation on toughening mechanisms are discussed. The results indicate that the whisker orientation, θ , is a decisive factor for the essential toughening mechanisms of whiskers. Only in the case of small θ and weak interface can whisker pullout occur, and whisker has maximum toughening effect. The results show that effects of whisker strengthening and toughening can be improved simultaneously through whisker oriented alignment. ©

Yongsheng Liu - One of the best experts on this subject based on the ideXlab platform.

  • fabrication of sic whisker reinforced sic Ceramic Matrix Composites based on 3d printing and chemical vapor infiltration technology
    Journal of The European Ceramic Society, 2019
    Co-Authors: Laifei Cheng, Shangwu Fan, Yongsheng Liu
    Abstract:

    Abstract Spray drying, binder jetting and chemical vapor infiltration (CVI) were used in combination for the first time to fabricate SiC whisker-reinforced SiC Ceramic Matrix Composites (SiCW/SiC). Granulated needle-shaped SiCW was spray dried into SiCW spherical particles to increase flowability and thereby increase printability. Then, binder jetting was employed to print a novel SiCW preform with two-stage pores using the SiCW spherical particles. The subsequent CVI technology produced pure, dense, and continuous SiC Matrix with high modulus and strength. Consequently, SiCW/SiC with appropriate mechanical properties was obtained. Finally, the challenges of the novel method and the ways to improve the mechanical properties of SiCW/SiC are discussed.

Laifei Cheng - One of the best experts on this subject based on the ideXlab platform.

  • fabrication of sic whisker reinforced sic Ceramic Matrix Composites based on 3d printing and chemical vapor infiltration technology
    Journal of The European Ceramic Society, 2019
    Co-Authors: Laifei Cheng, Shangwu Fan, Yongsheng Liu
    Abstract:

    Abstract Spray drying, binder jetting and chemical vapor infiltration (CVI) were used in combination for the first time to fabricate SiC whisker-reinforced SiC Ceramic Matrix Composites (SiCW/SiC). Granulated needle-shaped SiCW was spray dried into SiCW spherical particles to increase flowability and thereby increase printability. Then, binder jetting was employed to print a novel SiCW preform with two-stage pores using the SiCW spherical particles. The subsequent CVI technology produced pure, dense, and continuous SiC Matrix with high modulus and strength. Consequently, SiCW/SiC with appropriate mechanical properties was obtained. Finally, the challenges of the novel method and the ways to improve the mechanical properties of SiCW/SiC are discussed.

  • comparison of the mechanical hysteresis of carbon Ceramic Matrix Composites with different fiber preforms
    Carbon, 2009
    Co-Authors: Hui Mei, Laifei Cheng
    Abstract:

    Abstract The mechanical hysteresis of four Ceramic Matrix Composites with different carbon fiber preforms, i.e. needled C/SiC, 2D C/SiC, 2.5D C/SiC, and 3D C/SiC, was investigated and compared during cyclic reloading–unloading tests. An effective coefficient of the fiber volume fraction in the direction of loading (ECFL) was defined to characterize fiber architectures of the preforms. It is shown that an increase in permanent strain and a decrease in stiffness with the applied stress were strongly affected by the ECFL. The thermal residual stress (TRS) and ultimate tensile strength of the Composites are predicted theoretically related to the ECFL, and then validated by experimental results and microstructural observations. The predicted results not only demonstrate good agreement with experimental measurements, but also explain why differences in the composite ECFL result in substantial variations in TRS.

Yingdong Song - One of the best experts on this subject based on the ideXlab platform.

  • failure simulation of unidirectional fiber reinforced Ceramic Matrix Composites based on evolving compliant interfacial debonding model
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016
    Co-Authors: Zhigang Sun, Hongyan Shao, Xuming Niu, Yingdong Song
    Abstract:

    Abstract Damage and failure process of the unidirectional fiber-reinforced Ceramic Matrix Composites (FRCMCs) under tensile stress had been studied by many researchers in theoretical method. But because of some assumptions made in the theoretical model, it canot describe the performance of interface accurately. In this paper, evolving compliant interface (ECI) is employed to describe the properties of weak bonding interface. The ECI can respond the failure of debonding and sliding of interface efficiently. The whole damage evolution process of the material has been simulated by finite element method (FEM) and the stress-strain curve, the space of cracks at saturated state and the stress of components are discussed. The stress-strain curves of several Ceramic Composites were predicted by the model and compared with the experimental data. The results indicate that the tensile stress-strain curves agree well with the experimental data on consideration of Evolving compliant interfacial debonding model.

  • distribution of slip regions on the fiber Matrix interface of Ceramic Matrix Composites under arbitrary loading
    Journal of Reinforced Plastics and Composites, 2015
    Co-Authors: Sheng Zhang, Guangwu Fang, Yingdong Song
    Abstract:

    The distribution of slip regions on the fiber–Matrix interface of unidirectional fiber-reinforced Ceramic Matrix Composites is described to simulate the constitutive behavior under arbitrary loading and unloading. The appearance and disappearance of forward and reverse slip regions are discussed and the stress distribution when there are any number of forward and reverse slip regions is also provided. The interface slipping and constitutive behavior after closure of Matrix cracks under compressive loading are analyzed. Based on the distribution model of slip regions, the stress–strain response of unidirectional fiber-reinforced Ceramic Matrix Composites under arbitrary loading and unloading is calculated.

  • effect of Matrix cracking on hysteresis behavior of cross ply Ceramic Matrix Composites
    Journal of Composite Materials, 2014
    Co-Authors: L. B. Li, Yingdong Song, Youchao Sun
    Abstract:

    The effect of Matrix cracking on hysteresis behavior of cross-ply Ceramic Matrix Composites is investigated in the present analysis. The cracking of cross-ply Ceramic Composites was classified into five modes, where cracking mode 3 and mode 5 involve Matrix cracking and fiber/Matrix interface debonding in 0° ply. The Matrix crack space and interface debonded length are obtained by Matrix statistical cracking model and fracture mechanics interface debonding criterion. Based on the damage mechanisms of fiber sliding relative to Matrix in the interface debonded region, the unloading interface reverse slip length and reloading interface new slip length of cracking mode 3 and mode 5 are determined by the fracture mechanics approach. The hysteresis loops of four different cases for cracking mode 3 and mode 5 are derived respectively. The hysteresis loss energy as a function of interface shear stress of mode 3 and mode 5 are analyzed. The theoretical results have been compared with experimental data of two diffe...

  • hysteresis loop model of unidirectional carbon fiber reinforced Ceramic Matrix Composites under an arbitrary cyclic load
    Composites Part B-engineering, 2014
    Co-Authors: Xiguang Gao, Guangwu Fang, Yingdong Song
    Abstract:

    Abstract The microstructure of unidirectional fiber-reinforced Ceramic Matrix Composites is described by a cylindrical unit cell that is then discretized by a set of friction elements. Equilibrium equations resulting from the displacement increment balance between the fiber and Matrix are constructed and solved, and the distributions of stress and displacement are obtained. Interfacial debonding, fiber fracture and Matrix cracking are considered to simulate the hysteresis loops. Finally, the method developed in this paper is employed to study the interfacial sliding and hysteresis loops of a SiC/CAS composite subjected to arbitrary cyclic load. The results are discussed and compared with experimental data.

  • estimate interface shear stress of woven Ceramic Matrix Composites from hysteresis loops
    Applied Composite Materials, 2013
    Co-Authors: Longbiao Li, Yingdong Song
    Abstract:

    An approach to estimate the fiber/Matrix interface shear stress of woven Ceramic Matrix Composites during fatigue loading has been developed in this paper. Based on the analysis of the microstructure, the woven Ceramic Matrix Composites were divided into four elements of 0o warp yarns, 90o weft yarns, Matrix outside of the yarns and the open porosity. When Matrix cracking and fiber/Matrix interface debonding occur upon first loading to the peak stress, it is assumed that fiber slipping relative to Matrix in the interface debonded region of the 0o warp yarns is the mainly reason for the occurrence of the hysteresis loops of woven Ceramic Matrix composiets during unloading and subsequent reloading. The unloading interface reverse slip length and reloading interface new slip length are determined by the interface slip mechanisms. The hysteresis loops of three different cases have been derived. The hysteresis loss energy for the strain energy lost per volume during corresponding cycle is formulated in terms of the fiber/Matrix interface shear stress. By comparing the experimental hysteresis loss energy with the computational values, the fiber/Matrix interface shear stress of woven Ceramic Matrix Composites corresponding to different cycles can then be derived. The theoretical results have been compared with experimental data of two different woven Ceramic Composites.