WATER IMPACT LOADS ON CIRCULAR STRUCTURAL MEMBERS

When members of an offshore structure pass through the free surface, a n impact load results which can not be calculated by use of Morison's equation. The force is characterized as an impulsive load which is als o not treatable through static analyses since even though the member m ay be very stiff, its elastic properties have a profound effect on the resulting stress. Anew design method for computing stress in cylindri cal members due to impact is developed based on the energy principle w hich is shown to agree well with experiments. Subsequent to initial im pact the next peak in the stress is shown to be primarily a function o f the Froude number. The method is quite general and is convenient for application in design. Copyright (C) 1996 Elsevier Science Limited