Study on Fatigue Behavior Outside of Steel Beam SMA Honeycomb Stiffener
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.
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