Maximising the natural frequency of a beam with an intermediate elastic support

The minimum stiffness of a simple (or point) support that raises a natural frequency of a beam to its upper limit is investigated for different boundary conditions. The approach produces the closed-form solution for the minimum stiffness based on the derivative of a natural frequency with respect to the support position. It is seen that when an intermediate elastic support is positioned properly the effect is similar to a rigid support. The solution process also provides insight into the dynamics of a beam with an intermediate support for more general boundary conditions. The resulting solutions can be used to guide the practical design of a support.