钢横梁SMA蜂窝结构加劲肋面外疲劳性能研究

Study on Fatigue Behavior Outside of Steel Beam SMA Honeycomb Stiffener

针对某公路钢桁架桥工字型横梁腹板加劲肋下方出现纵向开裂问题,基于形状记忆合金(SMA)、蜂窝结构和波折腹板特性给出6种加劲肋方案:(1)横梁为原桥直腹板工字钢形状,有腹板间隙;(2)栓接钢板加固;(3)加劲肋为蜂窝结构,横梁为工字钢直板形状;(4)加劲肋为蜂窝结构,腹板为正弦波纹形状;(5)加劲肋为蜂窝结构,腹板为折线形状;(6)加劲肋下部抵住下翼缘板,不焊接。通过三维有限元数值模拟对不同加劲肋结构形式、有无SMA的蜂窝结构加劲肋腹板面外变形、疲劳应力幅和扭转角进行了比较研究。结果表明:腹板间隙处出现较大应力集中与变形扭转;栓接钢板加固、蜂窝结构加劲肋直腹板的抗面外变形疲劳效应效果显著,应力幅与位移都减少80%以上,蜂窝结构加劲肋直腹板相比于栓接钢板加固在提升抗扭转效应基础上钢材用量节约74.07%;蜂窝结构加劲肋折线腹板形式和加劲肋抵住下翼缘板方案不能有效加强抗扭刚度;使用SMA材料更有利于减少面外变形疲劳效应,最大应力幅减少可达77.86%,最大横向位移减少达到33.33%。综上所述,蜂窝结构加劲肋以更少的成本来增强横梁腹板抗面外变形与抗扭刚度。

To solve the longitudinal cracking problem under the I-beam web stiffener of steel truss bridge,based on shape memory alloy(SMA),honeycomb structure and corrugated web characteristics,6 stiffener schemes were proposed:(1) the I-beam web stiffener plate was the same as the studied bridge with web gaps;(2) retrofitting the stiffener plate with bolted steel plates;(3) the stiffening structure was honeycomb-shaped,and the beam was I-shaped with flat web;(4) the stiffener was honeycomb-shaped,and the web was sinusoidal corrugated shape;(5) the stiffener was honeycomb-shaped,and the web was corrugated shape;(6) the stiffening plate was close to the lower flange plate,no web gap,no welding.The external deformation,fatigue stress amplitude and torsion angle of honeycomb stiffeners with and without SMA were studied by using three-dimensional finite element numerical simulation.The result indicates that there are high localized stresses and deformations in the web near web gap.The distortion-induced deformation of bolted steel plates and honeycomb stiffener is minimized significantly.The maximum stress and displacement are reduced by more than 80%,.The steel honeycomb cost is reduced by 74.07% compared with that of bolted steel plates.The honeycomb stiffener with flat web are more effective in enhancing torsional stiffness than honeycomb with corrugated web.The use of SMA material is more beneficial to reduce the out-of-plane deformation.The maximum stress amplitude can be reduced by 77.86%,and the maximum transverse displacement can be reduced by 33.33%.In summary,the honeycomb stiffener with straight web is the preferred scheme which can enhance the torsional stiffness and resistance to distortion induced deformation with less cost.