Research on buckling collapse behavior and ultimate strength of stiffened plating in compression

本课题研究的课题及研究成果如下：(1)加筋板在轴向推力作用下的倒塌分析中考虑加劲肋的建模，发现最有效的建模方法是腹板模型和翼缘模型。(2)加筋板倾角对加筋板屈曲破坏行为的影响研究发现，倾角对加筋板局部屈曲强度没有影响，但对极限强度以外的承载力和整体屈曲强度有影响。(3) ISUM在加筋板复合荷载作用下的倒塌分析中的应用结合新的ISUM板单元和梁柱单元，较准确地模拟了连续加筋板在双轴和压力复合荷载作用下的倒塌行为。(4)弯曲加筋板的屈曲/塑性破坏行为研究发现，随着弯曲角的增大，弹性局部屈曲强度呈线性增加。另一方面，实际船舶结构中的弯曲板发生塑性屈曲，其极限抗压强度几乎等于屈服强度。(5)加劲肋残余应力对加筋板屈曲破坏行为的影响轧钢和焊接t型加劲肋腹板和凸缘残余应力的表现相反。然而，这种差异对加筋板的极限抗压强度影响不大。(6)加筋板脱扣对加筋板破坏行为的影响研究发现，在受弯受压侧的加筋腹板发生脱扣，这是由整体弯曲引起的。发生跳闸的条件是未知的。(7)铝加筋板的屈曲坍塌行为与强度焊接残余应力增大了铝加筋板的屈曲/极限强度。另一方面，热影响区材料的软化降低了铝加筋板的极限抗压强度。少

The items and results of research issues which have been studied in the present research project are as follows.(1)Consideration on modelling of stiffeners in the collapse analysis of stiffened panel under axial thrustIt was found that most effective modeling is to model the web by plate and the flange by beam-column.(2)Influence of inclination angle of stiffeners to plating on buckling collapse behavior of stiffened platesIt was found that inclination angle does not affect the local buckling strength, whereas it affects the capacity beyond the ultimate strength as well as the overall buckling strength.(3)Application of ISUM to collapse analysis of stiffened plates subjected to combined loadingCombining new ISUM plate element and beam-column element, collapse behavior of continuous stiffened plates under combined bi-axial and pressure loading was simulated very accurately.(4)Buckling/plastic collapse behavior of curved stiffened platesIt has been found that elastic local buckling stren … More gth increases linearly with the increase in curved angle. On the other hand, the curved plates in actual ship structure undergoes plastc buckling, and the ultimate compressive strength is nearly equal to the yielding strength.(5)Influence of residual stress in stiffeners on buckling collapse behavior of stiffened platesThe sign of the residual stress in web and flange opposite in rolled and welded T-type stiffeners. However, this difference affect a little on the ultimate compressive strength of stiffened plate.(6)Consideration on influence of stiffener tripping on collapse behavior of stiffened platesIt was found that tripping takes place at the stiffener web in the compression side of bending resulting from over-all bending. The condition for the occerrence of tripping is left unknown.(7)Buckling collaose behavior and strength of alminium stiffened platesThe welding residual stress increases the buckling/ultimate strength of alminium stiffened plate when the stiffened plate is fabricated by connecting rolled stiffened plates by butt-welding. On the other hand, softening of the material in heat affected zone reduce the ultimate compressive strength of alminium stiffened plates. Less