通气孔对新型不锈钢芯管平压性能影响分析

Influence of vent hole on flat compression performance of new stainless steel core pipe

不锈钢芯管作为不锈钢桥面芯板的重要传力构件,其平压力学性能与桥面板承载能力息息相关。因钎焊工艺要求,不锈钢芯管壁上开设有双通气圆孔。为研究双通气圆孔对不锈钢芯管平压性能的影响,开展2组不同厚度不锈钢芯管平压性能试验与有限元非线性屈曲分析。通过试验结果验证采用Riks弧长法进行不锈钢芯管非线性屈曲分析方法的正确性。并考虑圆孔直径d、偏心距e、芯管壁厚t等因素,建立不同规格不锈钢芯管模型,开展非线性屈曲分析,探究多参数协同作用下对不锈钢芯管平压性能的影响分析。研究结果表明:不锈钢芯管平压试验曲线表现出明显的非线性特征,分为弹性阶段、弹塑性阶段与塑性破坏阶段;通气孔、管端扳边处转角及管脚10 mm处易优先出现局部屈曲破坏;不锈钢芯管极限荷载Pu及其对应的压缩位移δ_(u)随孔径d、偏心距e的增加而减小,随壁厚t增加而增大;芯管极限荷载Pu受孔径d的影响大于受偏心距e的影响,增大孔径使芯管极限荷载Pu下降6.00%~15.51%,而增大偏心距使芯管极限荷载Pu下降0.64%~9.22%,芯管应规避在管身中部(e/H=0.5)开孔;当孔径比d/D≯0.04、偏心比e/H≯0.3时,通气孔对芯管极限承载力影响较小,对极限荷载下的压缩位移δ_(u)不产生影响,建议将其作为通气孔设计取值。研究中获得的临界值及变化规律可用于新型不锈钢桥面芯板结构设计与优化研究。

Stainless steel core pipe is an important force transmission component of stainless steel deck core plate,and its flat pressure performance is closely related to the bearing capacity of bridge deck.Due to the requirements of brazing process,the wall of the stainless steel core pipe is provided with a double ventilation round hole.In order to study the effect of double ventilation circular holes on the flat compression performance of stainless steel core pipe,two groups of stainless steel core tubes with different thicknesses were tested for flat compression performance and nonlinear buckling analysis by finite element method.The test results could verify the correctness of the nonlinear buckling analysis method of stainless steel core pipe by Riks arc length method.The factors such as the diameter d of circular hole,the eccentricity e and the wall thickness t of core tube were considered.The stainless steel core pipe models with different specifications were established.The nonlinear buckling analysis was carried out.The influence of multi-parameter synergy on the flat compression performance of stainless steel core pipe was explored.The research results are drawn as follows.The flat pressure test curve of stainless steel core tube can show obvious nonlinear characteristics.It can be divided into elastic stage,elasticplastic stage and plastic failure stage.The local buckling failure is easy to occur preferentially at the corner of vent hole,pipe end trimming and 10 mm pin.The ultimate load Pu of stainless steel core tube and its corresponding compression displacementδ_(u) decrease with the increase of aperture d and eccentricity e,increases with the increase of wall thickness t.The ultimate load Pu of the core tube is more influenced by the aperture d than by the eccentricity e,the ultimate load Pu decreases by 6.00%~15.51%by increasing the aperture.However,the increase eccentricity can reduce the ultimate load Pu of the core tube by 0.64%~9.22%.The core tube can avoid opening holes in the middle of the tube body(e/H=0.5).When aperture ratio d/D≯0.04 and eccentricity ratio e/H≯0.3,vent hole has little influence on the ultimate bearing capacity of the core tube,having no influence on the compression displacementδ_(u) under the ultimate load.It is suggested that it should be taken as the design value of vent hole.The critical value and variation law obtained in the study can be used for structural design and optimization of new stainless steel deck core plate.