The minimum support stiffness required to raise the fundamental natural frequency of plate structures

The minimum stiffness and optimum position of a flexible point support is calculated that raises the fundamental natural frequency of plate structures. For a single support the maximum fundamental natural frequency of the supported structure is equal to the second natural frequency of the unsupported structure. The structure is modelled using finite element analysis allowing a wide range of applications and boundary conditions. If a support is positioned within a finite element then the shape functions are used to calculate the contribution of the support to the system stiffness and also the slope of the mode at the support. Efficient methods are used to calculate the minimum support stiffness required. Numerical results demonstrate that a system with flexible supports may be designed with the same fundamental natural frequency as that of a system with rigid supports. Examples of plate structures with one or two point supports are analysed and show that the method is efficient in these cases.