A PRACTICAL FORMULA FOR ESTIMATING IMPULSIVE FORCE DUE TO DRIFTWOODS AND VARIATION FEATURES OF THE IMPULSIVE FORCE

Abstract

Small scale experiments in a channel and large scale experiments in the air are carried out to obtain a practical formula for estimating the impulsive force on structures due to a collision of driftwoods. Expression form of the formula is determined by considerations of a simplest equation of motion for driftwoods. An analytical method is also developed to examine the validity of the formula and variation features of the impulsive force synthetically. The method is based on the simplest elasto-plastic theory taken account of the collision angle of driftwoods, the deflection of structures and so on.