设置有四个信标节点发射固定频率的声波信号，在另一个z轴平面有一移动节点以一定速度移动(Set up four beacon nodes at a fixed frequency acoustic signal, in another z axis plane one mobile node move at a certain speed)

计算二维薄板应力与应变，采用平面四节点板单元，精度较高。(The stress and strain of two dimensional thin plate are calculated. The plane four node plate element is used to calculate the stress and strain of the plate.)