刚性结构通常采用“R ay le igh法”的线性化方法近似计算结构的基频,但是单层索网体系属于非线性预应力体系,其自振频率会随着振幅发生变化。通过分析结果表明,当节点质量较大时,用假定惯性荷载的方法计算的误差较大;“R ay le igh法...刚性结构通常采用“R ay le igh法”的线性化方法近似计算结构的基频,但是单层索网体系属于非线性预应力体系,其自振频率会随着振幅发生变化。通过分析结果表明,当节点质量较大时,用假定惯性荷载的方法计算的误差较大;“R ay le igh法”计算索网频率是基于微幅振动的假定,不能反映其振幅较大时的自振特性。本文采用连续化理论,推导了单层索网体系第一、二阶非线性自振频率近似公式,并将计算结果和瞬态分析结果进行对比,两者吻合较好。非线性自振特性的研究对于单层索网体系在风荷载作用下的响应分析具有十分重要的意义。展开更多
In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indi...In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack.展开更多
文摘刚性结构通常采用“R ay le igh法”的线性化方法近似计算结构的基频,但是单层索网体系属于非线性预应力体系,其自振频率会随着振幅发生变化。通过分析结果表明,当节点质量较大时,用假定惯性荷载的方法计算的误差较大;“R ay le igh法”计算索网频率是基于微幅振动的假定,不能反映其振幅较大时的自振特性。本文采用连续化理论,推导了单层索网体系第一、二阶非线性自振频率近似公式,并将计算结果和瞬态分析结果进行对比,两者吻合较好。非线性自振特性的研究对于单层索网体系在风荷载作用下的响应分析具有十分重要的意义。
基金Projects(41502283,41772309)supported by the National Natural Science Foundation of ChinaProject(2017YFC1501302)supported by the National Key Research and Development Program of ChinaProject(2017ACA102)supported by the Major Program of Technological Innovation of Hubei Province,China。
文摘In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack.
