不锈钢复合钢H形截面钢梁受剪承载性能

Shear Performance of Stainless-Clad Bimetallic Steel H-section Beams

基于复合钢本构模型,明确了复合比β对不锈钢复合钢应力-应变性能的影响。通过试验结果的承载曲线和破坏模式验证了数值模拟方法的准确性,进而以β、腹板宽高比a/hw和腹板高厚比hw/tw为变量开展300个数值模型的参数分析,系统分析了各变量对不锈钢复合钢H形截面钢梁受剪承载曲线和极限承载力的影响。研究结果表明:随着β的增加,不锈钢复合钢应力-应变曲线中的屈服平台逐渐消失,复合钢应力-应变性能逐渐由碳钢转变为不锈钢。当β较小时,不锈钢复合钢应力-应变曲线存在明显的屈服平台,这削弱了复合钢的应变强化对H形截面钢梁受剪承载性能的有利影响。随着β的增加,不锈钢复合钢的非线性应变强化性能逐渐增强,导致H形截面钢梁的延性性能逐渐提高,强度性能逐渐降低。经过验证,既有的欧洲规范设计公式对不锈钢复合钢H形截面钢梁受剪极限承载力的预测过于保守。基于参数分析结果,建立了考虑β影响的腹板贡献系数计算方法。研究结论有助于推广不锈钢复合钢的工程应用。

Based on the constitutive model of bimetallic steel,the effects of cladding ratioβon the stress-strain properties of the stainless-clad bimetallic steel(SBS)was clarified.The accuracy of the numerical method was verified through the bearing curve and failure mode of the experimental results.A parametric study including 300 numerical models was conducted,in which the parameters were β,aspect ratio of web a/hw and height to thickness ratio of web hw/tw.The effect of parameters on the shear bearing curve and ultimate bearing capacity of SBS H-section beams was systematically analyzed.The research results indicate that with increase in β,the yield plateau in the stress-strain curve of SBS increases,it gradually disappears,and the stress-strain performance of SBS gradually transforms from carbon steel to stainless steel.When β is relatively small,there is an obvious yield plateau in the stress-strain curve of SBS,which weakens the beneficial effect of strain hardening of SBS on the shear performance of H-section steel beams.With increase in β,the nonlinear strain hardening gradually strengthens.This leads to an improvement in the ductile performance and a gradual decrease in the strength performance of Hsection steel beams.After verification,the current European design formulas for predicting the shear ultimate bearing capacity of SBS H-section beams are too conservative.Based on the results of parameter analysis,the predictive method including effects of β was proposed for the contribution from web.The research conclusion is helpful for promoting the engineering application of SBS.