This paper investigates the related strength properties of 3D solid orthogonal panel fabrics under the condition of low strain, then analyses the response of these fabrics to low tensile loads, as well as presents how...This paper investigates the related strength properties of 3D solid orthogonal panel fabrics under the condition of low strain, then analyses the response of these fabrics to low tensile loads, as well as presents how it is possible to deduce the tensile properties of 3D solid orthogonal panel fabrics from the known properties of their constituent yarns and the fabric structural geometry while fabrics suffer from low strain (less than 10%). The experiments indicate that the relationship between stress and strain for 3D solid orthogonal panel fabrics is parabolic, and the relationship between fabric strain and yarn strain is linear. In addition, yarn strain is much less than fabric strain.展开更多
The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical...The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical method, respectively. An ellipse assumption for the cross-section of yarn was proposed in this analysis method with considering the yarn size and yarn-packing factor. Two types of local unit cell structures were identified for 4-step braided composites by considering the nature of the braiding processes and by observing the sample cross-sections. The relationship between the braiding procedure and the properties for 3-D braided structural shapes was established. This method provides the basis for analyzing stiffness and strength of 3-D braided composites.展开更多
We propose a novel 3-dimensional hollow waveguide with a variable air core for widely tunable devices.We observed a wavelength shift of 1.8 nm in a hollow waveguide resonator with a displacement of 6μm in an air core.
A staggered finite-volume technique for non-hydrostatic, small amplitude free surface flow governed by the incompressible Navier-Stokes equations is presented there is a proper balance between accuracy and computing t...A staggered finite-volume technique for non-hydrostatic, small amplitude free surface flow governed by the incompressible Navier-Stokes equations is presented there is a proper balance between accuracy and computing time. The advection and horizontal diffusion terms in the momentum equation are discretized by an integral interpolation method on the orthogonal unstructured staggered mesh and, while it has the attractive property of being conservative. The pressure-correction algorithm is employed for the non-hydrostatic pressure in order to achieve second-order temporal accuracy. A conservative scalar transport algorithm is also applied to discretize k - c equations in this model. The eddy viscosity is calculated from the k-c turbulent model. The resulting model is mass and momentum conservative. The model is verified by two examples to simulate unsteady small amplitude free surface flows where non-hydrostatic pressures have a considerable effect on the velocity field, and then applied to simulate the tidal flow in the Bohai Sea.展开更多
文摘This paper investigates the related strength properties of 3D solid orthogonal panel fabrics under the condition of low strain, then analyses the response of these fabrics to low tensile loads, as well as presents how it is possible to deduce the tensile properties of 3D solid orthogonal panel fabrics from the known properties of their constituent yarns and the fabric structural geometry while fabrics suffer from low strain (less than 10%). The experiments indicate that the relationship between stress and strain for 3D solid orthogonal panel fabrics is parabolic, and the relationship between fabric strain and yarn strain is linear. In addition, yarn strain is much less than fabric strain.
基金Aeronautical Science Foundation of China ( 99B2 3 0 0 1)
文摘The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical method, respectively. An ellipse assumption for the cross-section of yarn was proposed in this analysis method with considering the yarn size and yarn-packing factor. Two types of local unit cell structures were identified for 4-step braided composites by considering the nature of the braiding processes and by observing the sample cross-sections. The relationship between the braiding procedure and the properties for 3-D braided structural shapes was established. This method provides the basis for analyzing stiffness and strength of 3-D braided composites.
文摘We propose a novel 3-dimensional hollow waveguide with a variable air core for widely tunable devices.We observed a wavelength shift of 1.8 nm in a hollow waveguide resonator with a displacement of 6μm in an air core.
基金financially supported by the Science and Technology Project of the Ministry of Transport (Grant No. 2011329224170)
文摘A staggered finite-volume technique for non-hydrostatic, small amplitude free surface flow governed by the incompressible Navier-Stokes equations is presented there is a proper balance between accuracy and computing time. The advection and horizontal diffusion terms in the momentum equation are discretized by an integral interpolation method on the orthogonal unstructured staggered mesh and, while it has the attractive property of being conservative. The pressure-correction algorithm is employed for the non-hydrostatic pressure in order to achieve second-order temporal accuracy. A conservative scalar transport algorithm is also applied to discretize k - c equations in this model. The eddy viscosity is calculated from the k-c turbulent model. The resulting model is mass and momentum conservative. The model is verified by two examples to simulate unsteady small amplitude free surface flows where non-hydrostatic pressures have a considerable effect on the velocity field, and then applied to simulate the tidal flow in the Bohai Sea.
