Effects of a translating load on a floating plate - Structural drag and plate deformation

The elastic deformation of a structural plate floating on water caused by a translating three-dimensional load is investigated. The problem is akin to the landing and take-off of aircraft on a structural or ice sheet. The ini tial-boundary-value problem is solved analytically using a free-surface con dition that incorporates the flexural rigidity of the plate. The three-dime nsional load is modeled as an axisymmetric, translating pressure distributi on. The time-dependent analytical solution is used to obtain the unsteady d rag of this moving pressure, if it exists, as well as its asymptotic behavi or at large time. The behavior of the transition of the drag near a critica l speed related to the minimum celerity of the free waves of the hydroelast ic system is examined. Asymptotic analysis shows that the drag attains a di scontinuous but finite value as the translation speed approaches the critic al speed, an essential difference from some existing two-dimensional result s. The growth rate of the plate slope is found to be weakly singular, like log t, for large time. Comparisons with published experimental data for pla te deformation are made for the case of an ice sheet. The agreement is very favorable. Implications on the operation of floating runways are discussed . (C) 2000 Academic Press.