An analysis on a rigid-flexible coupling system of an oscillating massand a rotating disk

A mass-rod-disk system consisting of an oscillating mass attached to a rigid rotating disk by an elastic rod is designed to study rigid-flexible coupling mechanism.Suppose the rod is lightweight and has enough stiffness,the theorems of linear momentum and angular momentum are applied to the mass-rod-disk system based on the kinematic description of the system.With respect to two deflections of the mass and one angular velocity of the system,a group of nonlinear differential equations are established where the tangential inertial force,centrifugal force,Coriolis force as well as the moments of additional inertial forces take important effects on the dynamic response.For the sake of description,these three types of inertial forces mentioned before are referred to as additional inertial forces in this paper.The horizontal deflections of the mass and the angular velocity of the disk rotating about a fixed-axis are numerically solved for the prescribed external torque.The oscillating trajectory of the mass is deeply influenced by the additional inertial forces,meanwhile the dynamic fluctuations of the angular velocity and rotary inertia of the system are strongly affected by the mass oscillation.

Modified Bishop method for stability analysis of weakly sloped subgrade under centrifuge model test

The sliding forms of weak sloped and horizontal subgrades during the sliding process differ.In addition,the sliding form of weakly sloped subgrades exhibits considerable slippage and asymmetry.The accuracy of traditional slice methods for computing the stability safety factor of weakly sloped subgrades is insufficient for a subgrade design.In this study,a novel modified Bishop method was developed to improve the accuracy of the stability safety factor for different inclination angles.The instability mechanism of the weakly sloped subgrade was considered in the proposed method using the“influential force”and“additional force”concepts.The“additional force”reflected the weight effect of the embankment fill,whereas the“influential force”reflected the effect of the potential energy difference.Numerical simulations and experimental tests were conducted to evaluate the advantages of the proposed modified Bishop method.Compared with the traditional slice method,the error between the proposed method and the exact value is less than 32.3%in calculating the safety factor.