The forced state of the ball-screw of machine tool feeding system is analyzed. The ball-screw is simplified as Timoshenko beam and the differential equation of motion for the ball-screw is built. To obtain the axial v...The forced state of the ball-screw of machine tool feeding system is analyzed. The ball-screw is simplified as Timoshenko beam and the differential equation of motion for the ball-screw is built. To obtain the axial vibration equation,the differential equation of motion is simplified using the assumed mode method. Axial vibration equation is in form of Duffing equation and has the characteristics of nonlinearity. The numerical simulation of Duffing equation is proceeded by MATLAB / Simulink. The effect of screw length,exciting force and damping coefficient are researched,and the axial vibration phase track diagram and Poincare section are obtained. The stability and period of the axial vibration are analyzed. The limit cycle of phase track diagram is enclosed. Axial vibration has two type-center singularity distributions on both sides of the origin. The singularity attracts vibration to reach a stable state,and Poincare section shows that axial vibration appears chaotic motion and quasi periodic motion or periodic motion. Singularity position changes with the vibration system parameters,while the distribution doesn’ t change. The period of the vibration is enhanced with increasing frequency and damping coefficient. Test of the feeding system ball-screw axial vibration exists chaos movement. This paper provides a certain theoretical basis for the dynamic characteristic analysis of machine feeding system ball-screw and optimization of structural parameters.展开更多
In this work, we study charged current quasi-elastic scattering （QES） of vμ off nucleon and nucleus using a formalism based on the Llewellyn Smith （LS） model. Parameterizations by Galster et al. are used for elec...In this work, we study charged current quasi-elastic scattering （QES） of vμ off nucleon and nucleus using a formalism based on the Llewellyn Smith （LS） model. Parameterizations by Galster et al. are used for electric and magnetic Sach＇s form factors of the nucleons. We use the Fermi gas model along with the Pauli suppression condition to take into account the nuclear effects in the anti-neutrino-nucleus QES. We calculate vμ-p and vμ-^12C charged current quasi-elastic scattering differential and total cross sections for different values of axial mass MA, and compare the results with data from the GGM, SKAT, BNL, NOMAD, MINERVA and MiniBooNE experiments. The present theoretical approach gives a good description of differential cross section data. The calculations with axial mass MA =0.979 and 1.05 GeV are compatible with data from most of the experiments.展开更多
文摘The forced state of the ball-screw of machine tool feeding system is analyzed. The ball-screw is simplified as Timoshenko beam and the differential equation of motion for the ball-screw is built. To obtain the axial vibration equation,the differential equation of motion is simplified using the assumed mode method. Axial vibration equation is in form of Duffing equation and has the characteristics of nonlinearity. The numerical simulation of Duffing equation is proceeded by MATLAB / Simulink. The effect of screw length,exciting force and damping coefficient are researched,and the axial vibration phase track diagram and Poincare section are obtained. The stability and period of the axial vibration are analyzed. The limit cycle of phase track diagram is enclosed. Axial vibration has two type-center singularity distributions on both sides of the origin. The singularity attracts vibration to reach a stable state,and Poincare section shows that axial vibration appears chaotic motion and quasi periodic motion or periodic motion. Singularity position changes with the vibration system parameters,while the distribution doesn’ t change. The period of the vibration is enhanced with increasing frequency and damping coefficient. Test of the feeding system ball-screw axial vibration exists chaos movement. This paper provides a certain theoretical basis for the dynamic characteristic analysis of machine feeding system ball-screw and optimization of structural parameters.
基金Supported by Department of Science and Technology,New Delhi,India
文摘In this work, we study charged current quasi-elastic scattering （QES） of vμ off nucleon and nucleus using a formalism based on the Llewellyn Smith （LS） model. Parameterizations by Galster et al. are used for electric and magnetic Sach＇s form factors of the nucleons. We use the Fermi gas model along with the Pauli suppression condition to take into account the nuclear effects in the anti-neutrino-nucleus QES. We calculate vμ-p and vμ-^12C charged current quasi-elastic scattering differential and total cross sections for different values of axial mass MA, and compare the results with data from the GGM, SKAT, BNL, NOMAD, MINERVA and MiniBooNE experiments. The present theoretical approach gives a good description of differential cross section data. The calculations with axial mass MA =0.979 and 1.05 GeV are compatible with data from most of the experiments.
