The Experts below are selected from a list of 9135 Experts worldwide ranked by ideXlab platform
J.-m. Yang - One of the best experts on this subject based on the ideXlab platform.
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Effect of fiber coating on the fatigue crack initiation and multiplication of unnotched SCS-6/Ti3Al composites
Materials Science and Engineering: A, 1999Co-Authors: Yung-chiun Her, J.-m. Yang, P.c. WangAbstract:Abstract The effect of fiber coating on the fatigue crack initiation and multiplication of an unnotched SCS-6 fiber-reinforced titanium aluminide (Ti 3 Al) matrix composite was investigated. The initiation and growth of each individual matrix crack, the evolution of matrix crack density and Stiffness degradation of the composite with Ag/Ta-coated fibers were characterized quantitatively, and compared with those of the composite with uncoated fibers. The results showed that the composite with Ag/Ta-coated fibers exhibited a shorter crack initiation life, higher number of matrix cracks, and higher crack growth rate than the composite with uncoated fibers. Therefore, a higher matrix crack density and a lower Residual Stiffness were found in the composite with coated fibers during fatigue loading. The high interfacial cracking density and high interfacial bond strength in the Ag/Ta-coated SCS-6/Ti 3 Al composite is believed to be responsible for its poor fatigue damage resistance. Finally, an interface-controlled fatigue cracking model is used to predict the evolution of matrix crack density and Residual Stiffness of the composite under fatigue loading.
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Simulation of fatigue cracking and life distribution of SCS-6 fiber-reinforced orthorhombic titanium aluminide composites
Materials Science and Engineering: A, 1997Co-Authors: P.c. Wang, J.-m. YangAbstract:The evolution of matrix cracking, degradation of mechanical properties, and distribution of fatigue life of a SiC fiber-reinforced orthorhombic titanium aluminide (Ti-22Al-23Nb) composite under various applied cyclic stresses were analyzed by computer simulation. The propagation of matrix cracks was modeled by a modified fiber-bridging model which incorporates the effect of fiber breakage on crack growth. The Residual Stiffness was then predicted by using the shear-lag model, and the post-fatigue tensile strength was predicted by using the Residual load-carrying capacity of the fatigued composites as the failure criterion. Finally, the distribution of fatigue lives was predicted according to various fiber strength distributions simulated by a random number generator. The simulated matrix crack propagation rates, Residual Stiffness, Residual tensile strength and fatigue life are correlated with experimental results.
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Fatigue life prediction of fiber-reinforced titanium matrix composites
Acta Materialia, 1996Co-Authors: P.c. Wang, J.-m. Yang, S.m. Jeng, Ajit K. MalAbstract:A micromechanical model was developed to predict the fatigue life of SiC fiber-reinforced titanium matrix composites. The propagation of matrix cracks was modeled by calculating the stress concentration factor at the matrix crack tip in a fiber bridged center matrix crack. The Residual Stiffness was then predicted by using the partial-crack shear-lag model, and the post-fatigued tensile strength was predicted by using the load carrying capacity of fibers proposed previously for brittle matrix composites. Finally, the catastrophic failure and fatigue life of the composite was determined by Monte Carlo simulation. An integrated computer simulation code was developed to simulate the evolution of fatigue damage, degradation of mechanical properties, and to predict fatigue life. The predicted matrix crack propagation rates, Residual Stiffness, Residual tensile strength, and fatigue life were also correlated with experimental results.
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Fatigue Behavior of Scs-6/Titanium/Titan1ium Aluminide Hybrid Laminated Composite
MRS Proceedings, 1996Co-Authors: P.c. Wang, Y. C. Her, J.-m. YangAbstract:The fatigue behavior of the SCS-6 silicon carbide fiber-reinforced Ti-6Al-4V/Ti-25Al-10Nb hybrid laminated composite was investigated at room temperature. The accumulation of fatigue damage in the form of matrix cracking was measured as a function of loading cycles and applied stress levels. The Residual Stiffness and Residual tensile strength of the post-fatigued specimens were determined. The comparison of the crack growth behavior of the hybrid composite with both the SCS-6/Ti-6-4 and SCs-6/Ti-25-10 composites will also be discussed.
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Characterization and modeling of Stiffness reduction in SCS-6-Ti composites under low cycle fatigue loading
Materials Science and Engineering: A, 1995Co-Authors: P.c. Wang, S.m. Jeng, J.-m. YangAbstract:Abstract The Stiffness reduction and evolution of microstructural damage of a unidirectional silicon carbide fiber reinforced titanium matrix composite under tension-tension fatigue were investigated. Tests were conducted under load control with maximum applied stresses ranging from 750 to 945 MPa. The crack density of the interfacial reaction layer and matrix, matrix crack length, and interfacial debonding length as a function of fatigue cycles and applied stress levels were measured. The results showed that the composites exhibited an initial regime with slow Stiffness reduction, followed by a rapid Stiffness drop regime and a plateau regime with minimal change in Stiffness for the applied stress levels used in this study. The Residual Stiffness at N = 10 6 cycles is independent of the applied stress levels, while the microstructural damage accumulation varied with the applied stresses. A partial crack shear-lag model was also developed to predict the Residual Stiffness as a function of fatigue damage accumulation. Analytical simulation indicated that the profile of the Stiffness reduction curves was dominated by the matrix crack density, while the extent of Stiffness reduction was dominated by the matrix crack length.
P.c. Wang - One of the best experts on this subject based on the ideXlab platform.
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Effect of fiber coating on the fatigue crack initiation and multiplication of unnotched SCS-6/Ti3Al composites
Materials Science and Engineering: A, 1999Co-Authors: Yung-chiun Her, J.-m. Yang, P.c. WangAbstract:Abstract The effect of fiber coating on the fatigue crack initiation and multiplication of an unnotched SCS-6 fiber-reinforced titanium aluminide (Ti 3 Al) matrix composite was investigated. The initiation and growth of each individual matrix crack, the evolution of matrix crack density and Stiffness degradation of the composite with Ag/Ta-coated fibers were characterized quantitatively, and compared with those of the composite with uncoated fibers. The results showed that the composite with Ag/Ta-coated fibers exhibited a shorter crack initiation life, higher number of matrix cracks, and higher crack growth rate than the composite with uncoated fibers. Therefore, a higher matrix crack density and a lower Residual Stiffness were found in the composite with coated fibers during fatigue loading. The high interfacial cracking density and high interfacial bond strength in the Ag/Ta-coated SCS-6/Ti 3 Al composite is believed to be responsible for its poor fatigue damage resistance. Finally, an interface-controlled fatigue cracking model is used to predict the evolution of matrix crack density and Residual Stiffness of the composite under fatigue loading.
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Simulation of fatigue cracking and life distribution of SCS-6 fiber-reinforced orthorhombic titanium aluminide composites
Materials Science and Engineering: A, 1997Co-Authors: P.c. Wang, J.-m. YangAbstract:The evolution of matrix cracking, degradation of mechanical properties, and distribution of fatigue life of a SiC fiber-reinforced orthorhombic titanium aluminide (Ti-22Al-23Nb) composite under various applied cyclic stresses were analyzed by computer simulation. The propagation of matrix cracks was modeled by a modified fiber-bridging model which incorporates the effect of fiber breakage on crack growth. The Residual Stiffness was then predicted by using the shear-lag model, and the post-fatigue tensile strength was predicted by using the Residual load-carrying capacity of the fatigued composites as the failure criterion. Finally, the distribution of fatigue lives was predicted according to various fiber strength distributions simulated by a random number generator. The simulated matrix crack propagation rates, Residual Stiffness, Residual tensile strength and fatigue life are correlated with experimental results.
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Fatigue life prediction of fiber-reinforced titanium matrix composites
Acta Materialia, 1996Co-Authors: P.c. Wang, J.-m. Yang, S.m. Jeng, Ajit K. MalAbstract:A micromechanical model was developed to predict the fatigue life of SiC fiber-reinforced titanium matrix composites. The propagation of matrix cracks was modeled by calculating the stress concentration factor at the matrix crack tip in a fiber bridged center matrix crack. The Residual Stiffness was then predicted by using the partial-crack shear-lag model, and the post-fatigued tensile strength was predicted by using the load carrying capacity of fibers proposed previously for brittle matrix composites. Finally, the catastrophic failure and fatigue life of the composite was determined by Monte Carlo simulation. An integrated computer simulation code was developed to simulate the evolution of fatigue damage, degradation of mechanical properties, and to predict fatigue life. The predicted matrix crack propagation rates, Residual Stiffness, Residual tensile strength, and fatigue life were also correlated with experimental results.
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Fatigue Behavior of Scs-6/Titanium/Titan1ium Aluminide Hybrid Laminated Composite
MRS Proceedings, 1996Co-Authors: P.c. Wang, Y. C. Her, J.-m. YangAbstract:The fatigue behavior of the SCS-6 silicon carbide fiber-reinforced Ti-6Al-4V/Ti-25Al-10Nb hybrid laminated composite was investigated at room temperature. The accumulation of fatigue damage in the form of matrix cracking was measured as a function of loading cycles and applied stress levels. The Residual Stiffness and Residual tensile strength of the post-fatigued specimens were determined. The comparison of the crack growth behavior of the hybrid composite with both the SCS-6/Ti-6-4 and SCs-6/Ti-25-10 composites will also be discussed.
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Characterization and modeling of Stiffness reduction in SCS-6-Ti composites under low cycle fatigue loading
Materials Science and Engineering: A, 1995Co-Authors: P.c. Wang, S.m. Jeng, J.-m. YangAbstract:Abstract The Stiffness reduction and evolution of microstructural damage of a unidirectional silicon carbide fiber reinforced titanium matrix composite under tension-tension fatigue were investigated. Tests were conducted under load control with maximum applied stresses ranging from 750 to 945 MPa. The crack density of the interfacial reaction layer and matrix, matrix crack length, and interfacial debonding length as a function of fatigue cycles and applied stress levels were measured. The results showed that the composites exhibited an initial regime with slow Stiffness reduction, followed by a rapid Stiffness drop regime and a plateau regime with minimal change in Stiffness for the applied stress levels used in this study. The Residual Stiffness at N = 10 6 cycles is independent of the applied stress levels, while the microstructural damage accumulation varied with the applied stresses. A partial crack shear-lag model was also developed to predict the Residual Stiffness as a function of fatigue damage accumulation. Analytical simulation indicated that the profile of the Stiffness reduction curves was dominated by the matrix crack density, while the extent of Stiffness reduction was dominated by the matrix crack length.
Guodong Fang - One of the best experts on this subject based on the ideXlab platform.
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Random fatigue damage accumulation analysis of composite thin-wall structures based on Residual Stiffness method
Composite Structures, 2019Co-Authors: Guodong Fang, Xiaojie Chen, Jun LiangAbstract:Abstract The damage accumulation and life prediction for C/SiC composite panels subjected to random vibration loading was studied by using the Residual Stiffness model in combination with critical failure Stiffness ratios in the different stress levels. According to the results of Stiffness degradation and material S-N curves for constant-amplitude fatigue loadings, a new Residual Stiffness model was established and extended to adapt random stress states by using an equivalent damage ratio algorithm in time domain. The Stiffness degradation and material S-N curves were obtained by using constant amplitude fatigue experiments. Random vibration tests with limited-bandwidth excitation were conducted to verify the prediction model. Good agreement is observed compared with the results of 2D plain-woven C/SiC composite panel subjected to random vibration loadings.
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A frequency domain approach in Residual Stiffness estimation of composite thin-wall structures under random fatigue loadings
International Journal of Fatigue, 2019Co-Authors: Yuan Zhao, Jun Liang, Guodong FangAbstract:Abstract Based on the constant-amplitude fatigue experiment, a new Residual Stiffness model combining with power spectral density is proposed to adapt random stress states. The random loading process can be divided into multi-level variable amplitude loadings. All Stiffness degradation increments can be integrated to obtain the Stiffness degradation by using a numerical integral method. Fatigue damage accumulation of composite thin-wall structures subjected to random cyclic loadings is investigated by using the proposed method, which is also verified by random vibration tests with limited-bandwidth excitation. The influence of local Stiffness damage on the fundamental frequency of the experiment specimen is calculated by using finite element method, which is in good agreement with the experimental results. The life predictions based on the proposed Residual Stiffness model are more conservative in comparison of that with linear damage accumulation rule.
Jun Liang - One of the best experts on this subject based on the ideXlab platform.
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Random fatigue damage accumulation analysis of composite thin-wall structures based on Residual Stiffness method
Composite Structures, 2019Co-Authors: Guodong Fang, Xiaojie Chen, Jun LiangAbstract:Abstract The damage accumulation and life prediction for C/SiC composite panels subjected to random vibration loading was studied by using the Residual Stiffness model in combination with critical failure Stiffness ratios in the different stress levels. According to the results of Stiffness degradation and material S-N curves for constant-amplitude fatigue loadings, a new Residual Stiffness model was established and extended to adapt random stress states by using an equivalent damage ratio algorithm in time domain. The Stiffness degradation and material S-N curves were obtained by using constant amplitude fatigue experiments. Random vibration tests with limited-bandwidth excitation were conducted to verify the prediction model. Good agreement is observed compared with the results of 2D plain-woven C/SiC composite panel subjected to random vibration loadings.
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A frequency domain approach in Residual Stiffness estimation of composite thin-wall structures under random fatigue loadings
International Journal of Fatigue, 2019Co-Authors: Yuan Zhao, Jun Liang, Guodong FangAbstract:Abstract Based on the constant-amplitude fatigue experiment, a new Residual Stiffness model combining with power spectral density is proposed to adapt random stress states. The random loading process can be divided into multi-level variable amplitude loadings. All Stiffness degradation increments can be integrated to obtain the Stiffness degradation by using a numerical integral method. Fatigue damage accumulation of composite thin-wall structures subjected to random cyclic loadings is investigated by using the proposed method, which is also verified by random vibration tests with limited-bandwidth excitation. The influence of local Stiffness damage on the fundamental frequency of the experiment specimen is calculated by using finite element method, which is in good agreement with the experimental results. The life predictions based on the proposed Residual Stiffness model are more conservative in comparison of that with linear damage accumulation rule.
S.m. Jeng - One of the best experts on this subject based on the ideXlab platform.
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Fatigue life prediction of fiber-reinforced titanium matrix composites
Acta Materialia, 1996Co-Authors: P.c. Wang, J.-m. Yang, S.m. Jeng, Ajit K. MalAbstract:A micromechanical model was developed to predict the fatigue life of SiC fiber-reinforced titanium matrix composites. The propagation of matrix cracks was modeled by calculating the stress concentration factor at the matrix crack tip in a fiber bridged center matrix crack. The Residual Stiffness was then predicted by using the partial-crack shear-lag model, and the post-fatigued tensile strength was predicted by using the load carrying capacity of fibers proposed previously for brittle matrix composites. Finally, the catastrophic failure and fatigue life of the composite was determined by Monte Carlo simulation. An integrated computer simulation code was developed to simulate the evolution of fatigue damage, degradation of mechanical properties, and to predict fatigue life. The predicted matrix crack propagation rates, Residual Stiffness, Residual tensile strength, and fatigue life were also correlated with experimental results.
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Characterization and modeling of Stiffness reduction in SCS-6-Ti composites under low cycle fatigue loading
Materials Science and Engineering: A, 1995Co-Authors: P.c. Wang, S.m. Jeng, J.-m. YangAbstract:Abstract The Stiffness reduction and evolution of microstructural damage of a unidirectional silicon carbide fiber reinforced titanium matrix composite under tension-tension fatigue were investigated. Tests were conducted under load control with maximum applied stresses ranging from 750 to 945 MPa. The crack density of the interfacial reaction layer and matrix, matrix crack length, and interfacial debonding length as a function of fatigue cycles and applied stress levels were measured. The results showed that the composites exhibited an initial regime with slow Stiffness reduction, followed by a rapid Stiffness drop regime and a plateau regime with minimal change in Stiffness for the applied stress levels used in this study. The Residual Stiffness at N = 10 6 cycles is independent of the applied stress levels, while the microstructural damage accumulation varied with the applied stresses. A partial crack shear-lag model was also developed to predict the Residual Stiffness as a function of fatigue damage accumulation. Analytical simulation indicated that the profile of the Stiffness reduction curves was dominated by the matrix crack density, while the extent of Stiffness reduction was dominated by the matrix crack length.
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Fatigue Damage Evolution and Degradation of Mechanical Properties in Silicon-Carbide (SiC) Fiber-Reinforced Titanium Matrix Composites
Life Prediction Methodology for Titanium Matrix Composites, 1Co-Authors: S.m. Jeng, P.c. Wang, J.-m. YangAbstract:Fatigue damage accumulation and failure modes of several unidirectional and angle-ply SCS-6 fiber-reinforced titanium matrix composites are reviewed. The fatigue damage characteristics of the notched and unnotched composites were classified using several schematic diagrams based upon the constituent's properties and loading conditions. Quantitative relationships between the microstructural damage and Stiffness reduction were also established. A shear-lag model incorporating a damage function (which involved the cracking density and length, fiber/matrix frictional stress, and debonding length) was also used to predict Residual Stiffness of the composites.