板肋加劲板整体稳定数值模拟与受力机理研究

Study on Force Mechanism and Numerical Simulation of Overall Stability of Stiffened Panel with Plate Rib

分别采用梁单元与板壳单元建立同时考虑初始几何缺陷和焊接残余应力的受压板肋加劲板整体稳定分析有限元模型,并以相应试验结果进行验证,得到梁与板壳单元模拟受压板肋加劲板整体稳定的异同。采用经验证的数值模拟方法,对不同弯曲失稳方向板肋加劲板的受力机理进行了研究。结果表明:采用板壳单元可以较好还原板肋加劲板整体稳定受力性能,板壳有限元模型与试验试件的承载力最大相对误差为4.2%,平均相对误差为1.48%;梁单元模型与长(中长)柱试验试件的承载力最大相对误差为5.4%,平均相对误差为1.92%,与短柱试件的承载力相对误差虽仅为0.7%,但由于不能考虑板件发生的塑性失稳,其应力-位移曲线拟合情况相对较差;不同弯曲失稳方向板肋加劲板整体稳定构件的破坏特征不同,其中对于板肋侧弯曲的板肋加劲板整体稳定构件,被加劲板边缘部分受压达到材料屈服强度且板肋边缘受拉达到屈服强度时,构件整体达到其承载极限;对于被加劲板侧弯曲的板肋加劲板整体稳定构件,当板肋边缘部分受压达到材料屈服强度时,构件整体达到其承载极限;对于实际工程中组成钢箱梁顶板的板肋加劲板,制作时应避免朝向板肋侧的变形。

The finite element model for the overall stability analysis of the stiffened panel with plate rib under compression was established by using beam element and shell element respectively.The initial geometric defects and welding residual stress were considered and verified by the corresponding test results,and then the overall stability simulation difference of the stiffened panel with plate rib under compression between the beam and shell element was obtained.Using the verified numerical simulation method,the force mechanism of stiffened panel with plate rib in different bending instability directions was studied.The results show that the shell element can better restore the overall stability of the stiffened panel with plate rib.The maximum relative error between the shell finite element model and the test specimen is 4.2%,and the average relative error is 1.48%.The maximum bearing capacity relative error between the beam element model and the long(medium long)column test specimen is 5.4%,the average relative error is 1.92%.Although the bearing capacity relative error between the beam element model and the short column test specimen is only 0.7%,the fitting of the stress-displacement curve is relatively poor because the plastic instability of the plate can not be considered.The failure characteristics for the overall stability of stiffened panels with different bending instability directions are different.For the overall stable members of stiffened panel with bending on the side of the plate rib,when the edge of the stiffened panel is pressed to the material yield strength and the edge of the plate rib is pulled to the yield strength,the whole member reaches its bearing limit.For the overall stable member bending on the side of the stiffened panel,when the edge of the stiffened panel reaches the material yield strength,the whole member reaches its bearing limit.For the stiffened panel with ribs constituting the top plate of steel box girder in practical engineering,the deformation towards the side of plate ribs should be avoided in fabrication.