Effect of Asymmetric Hydrodynamic Impact on the Dynamic Response of a Plate Structure

Abstract

Due to the asymmetric water entry over a submerged part of a ship, the effect of the hydrodynamic impact on the dynamic response of a plate structure is investigated numerically by employing an orthogonal plate theory. The effect is found significant in the calculation. Both the deflection and the stress in the plate increase as the asymmetric degree under water entry of a bottom structure increases. Because of the structural dynamic effect, the maximum deflection at a heel angle of 20 degrees becomes about 50% more than that of the quasi-static approach, and the maximum stress in ydirection40% more than that of the quasi-state approach. The result of the present work proves the importance of asymmetrical hydrodynamic impact loading for structural design of a ship.基於船舶水下浸水面積於橫搖方向之非對稱分佈事實，本文乃以正交平板理論並佐以數值計算分析水動力衝擊之效應對浸水面板結構動態影響。數值結果發現板應力及變形撓度隨著非對稱現象增加而明顯增加，譬如於船舶橫傾角20度狀況下，板最大撓度值於非對稱效應之考量下較無考慮非對稱效應增加50％，而且於y向之最大應力值亦較無考慮非對稱效應大40％。本文結果將可提供船舶設計者，能考量船舶於水下浸水部分，非對稱效應衝擊力對結構強度之影響。