The natural frequencies in the range of 0-1000 rad / s are given. It can be seen that the natural frequencies of the system in the studied frequency range are 2 orders more than those without considering the foundation and foundation, and the values of other natural frequencies are also different.
Fig. 1 and Fig. 2 show the variation of natural frequencies with the foundation height h and the embedded depth E in the range of 0-1000 rad / s, respectively. It can be seen that the natural frequencies of each order decrease with the increase of the foundation height, but increase with the increase of the embedded depth. This is because the foundation height h and the embedded depth e will affect the mass stiffness of the foundation respectively, and then affect the natural frequency of the system. However, the natural frequencies of order 3, 4 and 5 are not sensitive to the change of embedded depth e, and the change with E is very small.
Fig. 3 shows the variation law of natural frequencies in the range of 0-1000rad / s with the size of the foundation bottom (assuming the length width ratio L / b of the foundation as a fixed value in the calculation). It can be seen that the natural frequencies of each order decrease with the increase of foundation width B. This is because, with the increase of foundation width b, the mass of foundation also increases, which leads to the decrease of natural frequency.