Papers by Author: Song Cen

Abstract: The procedure of beam subjected to transverse impact by bar is simulated using numerical method. The method considers the propagation of the expansion wave and shear wave in beam. The effect of beam height on elastic impact loads with different bar lengths and beam heights are investigated. With condition that the length of beam is longer than or equal to that of bar, the numerical solution shows that: when the bar length is constant, if the length of bar is shorter than the height of beam, the longer the bar, the bigger the peak value of impact force; the impact load curve consists of ascending and descending part basically; When the bar length is longer than or equal to beam height, the peak value of impact force is not related to the bar length and equal to that of bar with the same length as the beam height; the impact load curve is trapezium. The contact time is proportional to bar length and equal to the duration time of stress wave propagation in the bar for once return. If the bar length is constant, when bar length is shorter than beam height, the impact load is not related to beam height; when bar length longer than or equal to beam height, the peak value of impact force increases along with the beam height and approach to that of bar with the same length as the beam height.

Abstract: A new strategy of finite differences method is proposed for analysis of notched cross-section bars under elastic-plastic torsion. Relation curves of the elastic-plastic torque responding with different positions, angles and lengths of the notches in one section are obtained by numerical tests. It can be seen that these relation curves exhibit obvious nonlinearity. Meanwhile, the stress intensity factors can also be easily calculated by utilizing the results of above finite differences method. It provides an effective way for solving such elastic-plastic fracture mechanics problem.

Abstract: A new technique, Analytical Trial Function Method (ATFM), is proposed to formulate new finite element models for analysis of plane crack/notch problems. A new analytical finite element, named ATFM-CN, is successfully constructed. Furthermore, in order to determine the eigenvalues of the crack/notch problems, which utilized in above analytical trial functions, a modified sub-region accelerated Müller method is also suggested. Numerical examples show the present approach exhibits excellent performance in the analysis of stress-singularity problems.