受压T肋被加劲板局部稳定试验与计算方法

Local Stability Test and Calculation Method of T⁃rib Stiffened Plate Under Compression

为研究T肋被加劲板的受压局部稳定性能,考虑被加劲板宽度的变化,设计制作了2个Q345钢材强度和2个Q420钢材强度的焊接T肋加劲板试件进行被加劲板局部稳定轴压试验,并建立了有限元模型对破坏模式、失稳模态以及荷载位移曲线进行验证,采用6种尺寸的被加劲板局部稳定计算模型,分析了材料本构模型、简化焊接残余应力、局部初始几何缺陷对其受力性能的影响,得到了被加劲板局部稳定简化计算公式,并与各国规范稳定曲线进行对比。结果表明:被加劲板局部稳定试件与有限元模型均在试件1/2高度附近发生局部屈曲,平均应力-应变曲线总体趋势基本相同;随被加劲板宽厚比的增大,不同本构模型计算的稳定系数逐渐减小;采用简化残余应力分布的方式比数值模拟得到的稳定系数略小,计入残余应力加速了构件破坏;局部初始几何缺陷对试件稳定承载力的影响较大,当T肋加劲板的所有板件均计入局部初始几何缺陷时稳定系数最小;采用多项式拟合的被加劲板局部稳定简化公式曲线与欧洲规范曲线变化趋势较为接近,在相对宽厚比较大时超过了欧拉曲线,而采用Perry公式拟合的曲线与中国、美国规范曲线变化趋势较为接近,曲线整体均位于欧拉曲线的下方。

In order to study the local stability of T-shape stiffeners for steel plates under compression,considering the change of the stiffened plate width,two welded T-rib stiffened plates with Q345 steel strength and two welded T-rib stiffened plates with Q420 steel strength were designed to conduct the local stability axial compression test of the stiffened plate. The finite element model was established to verify the failure mode,instability mode and loaddisplacement curve. The local stability calculation models of the stiffened plate with six sizes were used to analyze the effects of different material constitutive models, simplified welding residual stress and local initial geometric imperfection on the mechanical properties of the stiffened plate. The simplified calculation formula of local stability of stiffened plate was obtained and compared with the stability curve of national codes. The results show that the local buckling occurs near the 1/2 height of the stiffened plate both in the test and the finite element model,and the overall trend of the average stress-strain curve is basically the same. With the increase of the width-thickness ratio of stiffened plate,the stability coefficient calculated by different constitutive models decreases. The stability coefficient obtained by simplifying the residual stress distribution is slightly smaller than that obtained by numerical simulation. The inclusion of residual stress accelerates the failure of the component. The local initial geometric imperfection has a greater impact on the stability bearing capacity of the specimen,and the stability coefficient is the smallest when all plates are included in the local initial geometric imperfection. The trend of the simplified formula curve of local stability of stiffened plate fitted by polynomial is close to the that of Eurocode code curve,and exceeds the Euler curve when the relative widththickness ratio is large,while the trend of curve fitted by Perry formula is close to that of Chinese and American codes,and the curves are all under the Euler curve.