This paper presents a new type of base isolation system, i. e. , slide-limited friction (S-LF) base isolation system . Based on this system, the harmonic and subharmonic periodic response of S-LF subjected to harmonic...This paper presents a new type of base isolation system, i. e. , slide-limited friction (S-LF) base isolation system . Based on this system, the harmonic and subharmonic periodic response of S-LF subjected to harmonic motions is investigated by using Fourier-Galerkin-Newton (FGN) method with Flo-quet theory. The dynamic response of S-LF subjected to earthquake ground motions is calculated with a high order precision direct integration method, and the numerical results are presented in maximum acceleration response spectra of superstructure and maximum sliding displacement response spectrum form. The comparison of isolating effects of S-LF, pure-friction base isolation system (P-F) and resilient-friction base isolation system (R-FBI) shows that the isolating property of S-LF is superior to those of P-F and R-FBI. Finally, by analyzing an engineering example, it is observed that the distribution of the maximum shear between floors and absolute acceleration of S-LF to earthquake ground motion is very different from that of traditional structures.展开更多
New plasticity solutions to the drained stability of conical slopes in homogeneous cohesive-frictional soils were investigated by axisymmetric finite element limit analysis. Three parameters were studied,i.e. excavate...New plasticity solutions to the drained stability of conical slopes in homogeneous cohesive-frictional soils were investigated by axisymmetric finite element limit analysis. Three parameters were studied,i.e. excavated height ratios, slope inclination angles, and soil friction angles. The influences of these parameters on the stability factor and predicted failure mechanism of conical slopes were discussed. A new design equation developed from a nonlinear regression of the lower bound solution was proposed for drained stability analyses of a conical slope in practice. Numerical examples were given to demonstrate a practical application of the proposed equation to stability evaluations of conical slopes with both associated and non-associated flow rules.展开更多
以电液伺服系统为研究对象,重点探究了非线性摩擦力对系统动态特征的影响规律.根据非线性动力学原理,建立了电液伺服系统的非线性动力学模型.通过理论研究,指出非线性摩擦力作用可以用Van Der Pol方程描述.通过数值试验分析,揭示了系统...以电液伺服系统为研究对象,重点探究了非线性摩擦力对系统动态特征的影响规律.根据非线性动力学原理,建立了电液伺服系统的非线性动力学模型.通过理论研究,指出非线性摩擦力作用可以用Van Der Pol方程描述.通过数值试验分析,揭示了系统内在的分岔现象及典型非线性动力学行为.用非线性动力学研究方法对实测的电液伺服系统的动态数据进行了深入分析,揭示了摩擦力引起的"极限环型振荡"现象.发现摩擦力的非线性作用会引起电液伺服系统在工作过程中发生非线性振动,其对系统动态特征的影响不容忽视,在系统建模与动态特性研究时应该将摩擦力的非线性作用考虑在内.展开更多
文摘This paper presents a new type of base isolation system, i. e. , slide-limited friction (S-LF) base isolation system . Based on this system, the harmonic and subharmonic periodic response of S-LF subjected to harmonic motions is investigated by using Fourier-Galerkin-Newton (FGN) method with Flo-quet theory. The dynamic response of S-LF subjected to earthquake ground motions is calculated with a high order precision direct integration method, and the numerical results are presented in maximum acceleration response spectra of superstructure and maximum sliding displacement response spectrum form. The comparison of isolating effects of S-LF, pure-friction base isolation system (P-F) and resilient-friction base isolation system (R-FBI) shows that the isolating property of S-LF is superior to those of P-F and R-FBI. Finally, by analyzing an engineering example, it is observed that the distribution of the maximum shear between floors and absolute acceleration of S-LF to earthquake ground motion is very different from that of traditional structures.
文摘New plasticity solutions to the drained stability of conical slopes in homogeneous cohesive-frictional soils were investigated by axisymmetric finite element limit analysis. Three parameters were studied,i.e. excavated height ratios, slope inclination angles, and soil friction angles. The influences of these parameters on the stability factor and predicted failure mechanism of conical slopes were discussed. A new design equation developed from a nonlinear regression of the lower bound solution was proposed for drained stability analyses of a conical slope in practice. Numerical examples were given to demonstrate a practical application of the proposed equation to stability evaluations of conical slopes with both associated and non-associated flow rules.
文摘以电液伺服系统为研究对象,重点探究了非线性摩擦力对系统动态特征的影响规律.根据非线性动力学原理,建立了电液伺服系统的非线性动力学模型.通过理论研究,指出非线性摩擦力作用可以用Van Der Pol方程描述.通过数值试验分析,揭示了系统内在的分岔现象及典型非线性动力学行为.用非线性动力学研究方法对实测的电液伺服系统的动态数据进行了深入分析,揭示了摩擦力引起的"极限环型振荡"现象.发现摩擦力的非线性作用会引起电液伺服系统在工作过程中发生非线性振动,其对系统动态特征的影响不容忽视,在系统建模与动态特性研究时应该将摩擦力的非线性作用考虑在内.
