A novel architectural Ti composite composed of network-woven structured TiB nanowires in a core-shell structured Ti matrix was fabricated to improve the strength of Ti matrix composites(TMCs),where the shell consists ...A novel architectural Ti composite composed of network-woven structured TiB nanowires in a core-shell structured Ti matrix was fabricated to improve the strength of Ti matrix composites(TMCs),where the shell consists of rich N solute atoms while the core is deficient of N solute atoms through spark plasma sintering of powder mixtures of Ti powder and BN nano-powder.The phase composition,morphology,element distribution,and mechanical properties of prepared samples were analyzed by X-ray diffraction(XRD),scanning electron microscope(SEM),electron probe microanalyzer(EPMA),and electronic universal material testing machine.The results indicate that the TMCs with designed architectures have been successfully achieved,and the as-prepared Ti-2BN(wt.%)composite exhibits an ultimate compressive strength of~1.8 GPa with a strain-to-fracture of~9%,while the Ti-1BN(wt.%)attains an ultimate compressive strength of~1.6 GPa and a strain-to-fracture of~20%.Moreover,the roles of the hybrid reinforcement structures in strengthening the Ti composites were discussed.展开更多
Knitted fabric is very different from woven fabric due to its more complicated knitting structures. The buckling of knitted fabric sheets subjected to simple shear in the wale direction is investigated analytically in...Knitted fabric is very different from woven fabric due to its more complicated knitting structures. The buckling of knitted fabric sheets subjected to simple shear in the wale direction is investigated analytically in consideration of the large deformation of fabric sheet in critical configuration. The theory on instability of finite deformation is applied to the analysis. All the stress boundary conditions of knitted fabric sheet are satisfied. An equation to determine the buckling direction angle is derived. It is shown that there are two possible buckling modes, flexural mode and barreling mode. The buckling condition equations for the flexural mode and barreling mode are also obtained respectively. Numerical illustrations reveal that only the flexural mode can actually occur and the barreling mode cannot, which agrees with the experimental observations. For a permitted buckling mode on margin boundaries, the critical value of shear amount and the buckling direction angle can be determined.展开更多
A preliminary investigation of shape memory (SM) effects of SMPU (shape memory polyurethane) knitting fabric is presented in this paper. Three SMPU knitted fabrics series with different content of SMPU fibers: 100% SM...A preliminary investigation of shape memory (SM) effects of SMPU (shape memory polyurethane) knitting fabric is presented in this paper. Three SMPU knitted fabrics series with different content of SMPU fibers: 100% SMPU, 50% SMPU and 50% cotton, 16% SMPU and 84% cotton are designed and manufactured in our lab. Their shape memory behaviors at different temperatures are characterized in terms of bagging. Our experimental results showed that shape memory effect can be improved with increasing content of SMPU fibers. A comparison between Lycra and SMPU knitted fabrics was also made to validate the shape memory effects of SMPU knitted fabrics.展开更多
基金supported by the Australian Research Council(No.LP130100913)the Baosteel-Australia Joint Research and Development Centre on the Project(No.BA110014LP)。
文摘A novel architectural Ti composite composed of network-woven structured TiB nanowires in a core-shell structured Ti matrix was fabricated to improve the strength of Ti matrix composites(TMCs),where the shell consists of rich N solute atoms while the core is deficient of N solute atoms through spark plasma sintering of powder mixtures of Ti powder and BN nano-powder.The phase composition,morphology,element distribution,and mechanical properties of prepared samples were analyzed by X-ray diffraction(XRD),scanning electron microscope(SEM),electron probe microanalyzer(EPMA),and electronic universal material testing machine.The results indicate that the TMCs with designed architectures have been successfully achieved,and the as-prepared Ti-2BN(wt.%)composite exhibits an ultimate compressive strength of~1.8 GPa with a strain-to-fracture of~9%,while the Ti-1BN(wt.%)attains an ultimate compressive strength of~1.6 GPa and a strain-to-fracture of~20%.Moreover,the roles of the hybrid reinforcement structures in strengthening the Ti composites were discussed.
基金Supported by National Natural Science Foundation of Chinathe Royal Society of UKunder their joint grant scheme
文摘Knitted fabric is very different from woven fabric due to its more complicated knitting structures. The buckling of knitted fabric sheets subjected to simple shear in the wale direction is investigated analytically in consideration of the large deformation of fabric sheet in critical configuration. The theory on instability of finite deformation is applied to the analysis. All the stress boundary conditions of knitted fabric sheet are satisfied. An equation to determine the buckling direction angle is derived. It is shown that there are two possible buckling modes, flexural mode and barreling mode. The buckling condition equations for the flexural mode and barreling mode are also obtained respectively. Numerical illustrations reveal that only the flexural mode can actually occur and the barreling mode cannot, which agrees with the experimental observations. For a permitted buckling mode on margin boundaries, the critical value of shear amount and the buckling direction angle can be determined.
基金Project support by the Study of Temperature-Sensitive Shape-Memory Polymers for Smart Textile Applications, Shape MemoryCenter of Hong Kong Polytechnic University, HK, China
文摘A preliminary investigation of shape memory (SM) effects of SMPU (shape memory polyurethane) knitting fabric is presented in this paper. Three SMPU knitted fabrics series with different content of SMPU fibers: 100% SMPU, 50% SMPU and 50% cotton, 16% SMPU and 84% cotton are designed and manufactured in our lab. Their shape memory behaviors at different temperatures are characterized in terms of bagging. Our experimental results showed that shape memory effect can be improved with increasing content of SMPU fibers. A comparison between Lycra and SMPU knitted fabrics was also made to validate the shape memory effects of SMPU knitted fabrics.
