Kashani Rad Hooman, Ghalehnovi Mansour, Shariatmadar Hashem
Dept. of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
Heliyon. 2019 Jun 21;5(6):e01919. doi: 10.1016/j.heliyon.2019.e01919. eCollection 2019 Jun.
The Boundary Characteristic Orthogonal Polynomials (BCOP) method is used in this study in order to analyze multi-span plates traversed by a moving inertia load traveling on an arbitrary path with constant velocity. The plate is assumed to be free from any support at the longitudinal edges and the spans are made by simply supported constraints at width, i.e. SFSF. The plate's mode shapes are generated by the BCOP method while the boundary condition is satisfied over all computational modes. A free vibration analysis is done in order to find natural frequency. The governing differential equations of motion are derived by Hamilton's principle and the solution in the time domain is found by using the Matrix Exponential method after modeling the problem in state space. All of the convective inertia terms are included in the acceleration derivatives and the responses are presented both for the load moving on the plate's surface ignoring/including the mass inertia effect. A comprehensive parametric study on the plate's mid-spans is carried out for the single, two- and three-span plates, investigating Dynamic Amplification Factor (DAF) versus non-dimensional velocity (V). The effect of mass and aspect ratio along with the location of reference point of calculation on the dynamic behavior of a multi-span plate is investigated and many graphs are generated as spectra. One can easily find the critical velocity as well as the peak deflection for each case study by introducing a corrective factor. The solution under moving mass excitation is obtained by the factor if the same response for moving load is known.
本研究采用边界特征正交多项式(BCOP)方法,以分析在任意路径上匀速移动的惯性载荷作用下的多跨板。假设板在纵向边缘无任何支撑,各跨在宽度方向上采用简支约束,即SFSF。利用BCOP方法生成板的振型,同时在所有计算模态上满足边界条件。进行自由振动分析以确定固有频率。通过哈密顿原理推导运动控制微分方程,并在状态空间对问题进行建模后,采用矩阵指数法求解时域解。所有对流惯性项都包含在加速度导数中,分别给出了忽略/考虑质量惯性效应时载荷在板表面移动的响应。对单跨、两跨和三跨板的板中跨进行了全面的参数研究,研究了动力放大系数(DAF)与无量纲速度(V)的关系。研究了质量、长宽比以及计算参考点位置对多跨板动力行为的影响,并生成了许多频谱图。通过引入校正因子,可轻松找到每个案例研究的临界速度以及峰值挠度。如果已知移动载荷的相同响应,则可通过该因子获得移动质量激励下的解。