Research on the flange plate of the comb-type caisson

The comb-type breakwater is a new type of vertical breakwater. The flange plate is the major structural component of the comb-type breakwater. The mechanical properties of the flange plate are vital for the design of the comb-type breakwater. In the paper, following a series of experimental study on the hydraulic performance of the new comb-type vertical breakwater, the extreme wave load acting on the flange plate with different design water levels, wave heights and periods are given. The calculation errors based on the theories of thick-plate and thin-plate are analyzed. An eight-node isoparametric thick plate element for the flange plate is proposed. By this means, the computing accuracy is improved. Then, a finite element method (FEM) has been used to study the distribution of extreme stress on the semi-submersible flange plate with different boundary conditions. Furthermore, the natural vibration characteristic of the flange plate is also analyzed. The relationships of parameters between the thickening coefficient of frequency and the ratio of thickness to span, the series of mode, the ratio of length to width are studied. An effective formula for calculating the natural periods of the flange plate with one edge clamped is derived.