采用JQW03单纤维压缩弯曲仪对细度相近的超细羊毛、羊绒进行弯曲压缩性能测试,通过对测试得到的峰值力、等效弯曲模量、抗弯刚度和弯曲压缩曲线进行对比分析,得出超细羊毛和羊绒纤维在弯曲压缩性能上的差异。实验结果表明:羊绒纤维的峰...采用JQW03单纤维压缩弯曲仪对细度相近的超细羊毛、羊绒进行弯曲压缩性能测试,通过对测试得到的峰值力、等效弯曲模量、抗弯刚度和弯曲压缩曲线进行对比分析,得出超细羊毛和羊绒纤维在弯曲压缩性能上的差异。实验结果表明:羊绒纤维的峰值力、抗弯刚度和等效弯曲模量均小于超细羊毛纤维,超细羊毛弯曲压缩过程所受的弯曲载荷在0.25 m N左右,而羊绒所受的弯曲载荷在0.25 m N以下,即在同样的条件下,羊绒更容易被压弯,也就是羊绒纤维比超细羊毛纤维柔软;羊毛的弯曲压缩曲线较平缓,羊绒纤维的弯曲压缩曲线出现多峰。展开更多
The crucial effect of compressibility of rods on their instability is novelly demonstrated via singularity theory. It is shown that the critical load of compressible rod is always greater than the one of the Euler rod...The crucial effect of compressibility of rods on their instability is novelly demonstrated via singularity theory. It is shown that the critical load of compressible rod is always greater than the one of the Euler rod, and a subcritical pitchfork bifurcation, which cannot occur for the Euler rod, may occur for a compressible rod. A whole bifurcation diagram of compressible rods is as follows ： when the original slenderness ratio of a compressible rod, $o is smaller than （1 ＋ v/3 √3π/2,, the rod does not buckle; when So∈ [1＋ v/3）3√3π/2 ,（1＋v/5）5 5√5π/4）,the rod may undergo a subcritical pitchfork bifurcation and a collapse may occur; when So ∈ [1＋ v/5）5√5π/4 ＋ ∞）, the rod may undergo a supercritical pitchfork bifurcation. The deformation of cross section of rods causes a little shift of bifurcation points towards to the one corresponding to larger slenderness ratio.展开更多
Concrete Filled FRP （Reinforced Polymeric Plastic） Tubes （CFFT） and Reinforced Concrete Filled FRP Tubes （RCFFT） are known to have the capability to enhance structural performance in terms of structural stabilit...Concrete Filled FRP （Reinforced Polymeric Plastic） Tubes （CFFT） and Reinforced Concrete Filled FRP Tubes （RCFFT） are known to have the capability to enhance structural performance in terms of structural stability, ductility, as well as chemical resistance when compared with conventional concrete members. In this study, the authors evaluate the structural performance of the CFFT and the RCFFT through flexural tests for the purpose of applying the members as flexural ones. Moreover, the compressive behavior of the CFFT and the RCFFT members was investigated to examine their confinement effects. Based on the experimental and analytical results of the compressive behavior of the members, equations for estimating the ultimate compressive strengths of the CFFT and the RCFFT were proposed. In addition, the degree of improvement on the flexural performance of the RCFFT member strengthened by the FRP was analyzed from the flexural tests.展开更多
The use of advanced carbon nanomaterials for flexible antenna sensors has attracted great attention due to their outstanding electromechanical properties. However, carbon nanomaterial based composites have yet to over...The use of advanced carbon nanomaterials for flexible antenna sensors has attracted great attention due to their outstanding electromechanical properties. However, carbon nanomaterial based composites have yet to overcome drawbacks, such as low conductivity and toughness. In this work, a flexible multi-layer graphene film(FGF) with a high conductivity of 10~6 S/m for antenna based wearable sensors is investigated. A 1.63 GHz FGF antenna sensor exhibits significantly high strain sensitivity of 9.8 for compressive bending and 9.36 for tensile bending, which is super than the copper antenna sensor(5.39 for compressive bending and 4.05 for tensile bending). Moreover, the FGF antenna sensor shows very good mechanical flexibility, reversible deformability and structure stability, and thus is well suited for applications like wearable devices and wireless strain sensing.展开更多
文摘采用JQW03单纤维压缩弯曲仪对细度相近的超细羊毛、羊绒进行弯曲压缩性能测试,通过对测试得到的峰值力、等效弯曲模量、抗弯刚度和弯曲压缩曲线进行对比分析,得出超细羊毛和羊绒纤维在弯曲压缩性能上的差异。实验结果表明:羊绒纤维的峰值力、抗弯刚度和等效弯曲模量均小于超细羊毛纤维,超细羊毛弯曲压缩过程所受的弯曲载荷在0.25 m N左右,而羊绒所受的弯曲载荷在0.25 m N以下,即在同样的条件下,羊绒更容易被压弯,也就是羊绒纤维比超细羊毛纤维柔软;羊毛的弯曲压缩曲线较平缓,羊绒纤维的弯曲压缩曲线出现多峰。
基金Supported by National Natural Science Foundation of China(No. 10272079)joint grant from National Natural Science Foundation of Chinathe Royal Society of UK under their Joint Project Scheme
文摘The crucial effect of compressibility of rods on their instability is novelly demonstrated via singularity theory. It is shown that the critical load of compressible rod is always greater than the one of the Euler rod, and a subcritical pitchfork bifurcation, which cannot occur for the Euler rod, may occur for a compressible rod. A whole bifurcation diagram of compressible rods is as follows ： when the original slenderness ratio of a compressible rod, $o is smaller than （1 ＋ v/3 √3π/2,, the rod does not buckle; when So∈ [1＋ v/3）3√3π/2 ,（1＋v/5）5 5√5π/4）,the rod may undergo a subcritical pitchfork bifurcation and a collapse may occur; when So ∈ [1＋ v/5）5√5π/4 ＋ ∞）, the rod may undergo a supercritical pitchfork bifurcation. The deformation of cross section of rods causes a little shift of bifurcation points towards to the one corresponding to larger slenderness ratio.
文摘Concrete Filled FRP （Reinforced Polymeric Plastic） Tubes （CFFT） and Reinforced Concrete Filled FRP Tubes （RCFFT） are known to have the capability to enhance structural performance in terms of structural stability, ductility, as well as chemical resistance when compared with conventional concrete members. In this study, the authors evaluate the structural performance of the CFFT and the RCFFT through flexural tests for the purpose of applying the members as flexural ones. Moreover, the compressive behavior of the CFFT and the RCFFT members was investigated to examine their confinement effects. Based on the experimental and analytical results of the compressive behavior of the members, equations for estimating the ultimate compressive strengths of the CFFT and the RCFFT were proposed. In addition, the degree of improvement on the flexural performance of the RCFFT member strengthened by the FRP was analyzed from the flexural tests.
基金supported by the National Natural Science Foundation of China(51701146)the Natural Science Foundation of Hubei Province of China(2015CFB719)the Fundamental Research Funds for the Central Universities(WUT:2017IB015)
文摘The use of advanced carbon nanomaterials for flexible antenna sensors has attracted great attention due to their outstanding electromechanical properties. However, carbon nanomaterial based composites have yet to overcome drawbacks, such as low conductivity and toughness. In this work, a flexible multi-layer graphene film(FGF) with a high conductivity of 10~6 S/m for antenna based wearable sensors is investigated. A 1.63 GHz FGF antenna sensor exhibits significantly high strain sensitivity of 9.8 for compressive bending and 9.36 for tensile bending, which is super than the copper antenna sensor(5.39 for compressive bending and 4.05 for tensile bending). Moreover, the FGF antenna sensor shows very good mechanical flexibility, reversible deformability and structure stability, and thus is well suited for applications like wearable devices and wireless strain sensing.
