New and high transparent structural element, steel-glass composite beam was developed in respect to fabrication, static-structural and architectural criteria and consists of steel flanges and glass web assembled toget...New and high transparent structural element, steel-glass composite beam was developed in respect to fabrication, static-structural and architectural criteria and consists of steel flanges and glass web assembled together by semi-rigid polymer adhesive, which is the key element of whole composite system. These beams can be used mainly as members of high transparent roof or floor structure as well as stiffening fins for large area glass facades. This paper deals with experimental research performed at CTU （Czech Technical University） Prague, which started by adhesive selection and initial material tests by ISO527, continued via small-scale steel-glass connection tests and graduated by full-scale tests of hybrid beams with the span of 4 m. Generalized results of these experiments, analytical and numerical studies serve as device, how to accurately predict the behavior of the beam, describe the stress distribution along the cross section and safely and economically design such a kind of structure with semi-rigid shear connection, made by polymer adhesive.展开更多
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
Bending tests were conducted on 23 ferrocement slab specimens with steel meshes and continuous CFRP fibers. Two, or three, or four CFRP slices are gathered as a rope and hence these ropes are arranged to form a grid t...Bending tests were conducted on 23 ferrocement slab specimens with steel meshes and continuous CFRP fibers. Two, or three, or four CFRP slices are gathered as a rope and hence these ropes are arranged to form a grid tied to a skeletal frame. The three patterns of slice reinforcement were used to reinforce cementitious slabs with or without conventional wire mesh reinforcement. The slabs were square and simply supported at their periphery with a clear span of 400 mm, and concentrically patch loaded to failure. For specimens designed to fail in flexure, the specimens reinforced with CFRP slices showed a smoother load deflection response and higher flexural capacity. For slabs designed to fail in punching shear, adding CFRP slices showed significant improvement in the ultimate shear capacity and ductility over reference specimens. Well distributed fine cracks of smaller width than control specimens were developed and no matrix spalling was observed.展开更多
We propose a novel metamaterial structure operating at the terahertz band. This structure is assembled by a split ring resonator (SRR) with a metal mesh within a unit cell. Our experimental studies on the composite st...We propose a novel metamaterial structure operating at the terahertz band. This structure is assembled by a split ring resonator (SRR) with a metal mesh within a unit cell. Our experimental studies on the composite structure indicate that the coupling of the SRR and metal mesh significantly contribute to the transparency at the terahertz range. Moreover, we experimentally demonstrated the verity of transmission peak of this structure by changing the relative positions of the SRR and the metal mesh. The simulated electric field redistributions support the dependence between position of the two components and the transmission response. This study is the first to report a hybrid metamaterial structure consisting of an SRR array and a metal mesh within a unit cell. The designed process and resonance characteristics of this composite structure make it an excellent candidate for developing tunable terahertz components via integration with the MEMS (Micro Electronic Mechanical System) technology.展开更多
文摘New and high transparent structural element, steel-glass composite beam was developed in respect to fabrication, static-structural and architectural criteria and consists of steel flanges and glass web assembled together by semi-rigid polymer adhesive, which is the key element of whole composite system. These beams can be used mainly as members of high transparent roof or floor structure as well as stiffening fins for large area glass facades. This paper deals with experimental research performed at CTU （Czech Technical University） Prague, which started by adhesive selection and initial material tests by ISO527, continued via small-scale steel-glass connection tests and graduated by full-scale tests of hybrid beams with the span of 4 m. Generalized results of these experiments, analytical and numerical studies serve as device, how to accurately predict the behavior of the beam, describe the stress distribution along the cross section and safely and economically design such a kind of structure with semi-rigid shear connection, made by polymer adhesive.
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.
文摘Bending tests were conducted on 23 ferrocement slab specimens with steel meshes and continuous CFRP fibers. Two, or three, or four CFRP slices are gathered as a rope and hence these ropes are arranged to form a grid tied to a skeletal frame. The three patterns of slice reinforcement were used to reinforce cementitious slabs with or without conventional wire mesh reinforcement. The slabs were square and simply supported at their periphery with a clear span of 400 mm, and concentrically patch loaded to failure. For specimens designed to fail in flexure, the specimens reinforced with CFRP slices showed a smoother load deflection response and higher flexural capacity. For slabs designed to fail in punching shear, adding CFRP slices showed significant improvement in the ultimate shear capacity and ductility over reference specimens. Well distributed fine cracks of smaller width than control specimens were developed and no matrix spalling was observed.
基金supported by the Program of "One Hundred Talented People" of the Chinese Academy of Sciences and the Organization Department of Sichuanthe National Natural Science Foundation of China (Grant No.11176033)the Natural Science Foundation of Beijing (Grant No.4102016)
文摘We propose a novel metamaterial structure operating at the terahertz band. This structure is assembled by a split ring resonator (SRR) with a metal mesh within a unit cell. Our experimental studies on the composite structure indicate that the coupling of the SRR and metal mesh significantly contribute to the transparency at the terahertz range. Moreover, we experimentally demonstrated the verity of transmission peak of this structure by changing the relative positions of the SRR and the metal mesh. The simulated electric field redistributions support the dependence between position of the two components and the transmission response. This study is the first to report a hybrid metamaterial structure consisting of an SRR array and a metal mesh within a unit cell. The designed process and resonance characteristics of this composite structure make it an excellent candidate for developing tunable terahertz components via integration with the MEMS (Micro Electronic Mechanical System) technology.
