A bidirectional functionally graded Sandwich (BFGSW) beam model made from three distinct materials is proposed and its dynamic behavior due to nonuniform motion of a moving point load is investigated for the first time. The beam consists of three layers, a homogeneous core, and two functionally graded face sheets with material properties varying in both the thickness and longitudinal directions by power gradation laws. Based on the first-order shear deformation beam theory, a finite beam element is derived and employed in computing dynamic response of the beam. The element which used the shear correction factor is simple with the stiffness and mass matrices evaluated analytically. The numerical result reveals that the material distribution plays an important role in the dynamic response of the beam, and the beam can be designed to meet the desired dynamic magnification factor by appropriately choosing the material grading indexes. A parametric study is carried out to highlight the effects of the material distribution, the beam layer thickness and aspect ratios, and the moving load speed on the dynamic characteristics. The influence of acceleration and deceleration of the moving load on the dynamic behavior of the beam is also examined and highlighted.

中文翻译：

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双向功能梯度夹层梁在运动荷载非均匀运动下的动力特性

提出了一种由三种不同材料制成的双向功能梯度三明治（BFGSW）梁模型，并首次研究了由于移动点载荷的不均匀运动而引起的动态行为。光束由三层组成，均质的芯和两个功能渐变的面板，其材料特性在厚度和纵向上均随功率渐变定律而变化。基于一阶剪切变形梁理论，推导了有限元单元，并将其用于梁的动力响应计算。使用剪切校正因子的元素很简单，其刚度和质量矩阵均经过分析评估。数值结果表明，材料分布在梁的动力响应中起着重要作用，并且光束可以被设计通过适当地选择材料分级指数以满足期望的动态放大系数。进行了参数研究，以突出材料分布，梁层厚度和纵横比以及移动载荷速度对动态特性的影响。还检查并强调了移动负载的加减速对梁的动力学行为的影响。