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Compressive and Bending Resistance of Thin-walled Hat Section Beam with Strengthened Ridgelines
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on April 06, 2021 by SAE International in United States
Event: SAE WCX Digital Summit
To overcome some drawbacks of using UHSS (Ultra High Strength Steel) in vehicle weight reduction, like spot weld HAZ (Heat Affected Zone) softening, hard machining and brittleness, a new solution of ultra-high stress strengthening was proposed and applied to the ridgelines of thin-walled structures in this paper. Firstly, stress distribution characteristics，laws of stress varying and compressed plate buckling process of the thin-walled rectangular beam under compression and bending load was analyzed in elastic-plastic stage by theory and FE simulation. Secondly, based on elastic-plastic buckling theory of the compressed plate and stress distribution similarity of the buckling process of thin-walled box structure, three factors influencing the limit resistance enhancement of thin-walled hat section beam were found in theoretical derivation, and the rationality and accuracy of cross section limit resistance prediction formulas were also verified by FE simulation. Finally, compared with the bending and compression resistance of the original thin-walled hat section beam, it shows that the bending and compression resistance of the same thin-walled hat section beam was improved significantly by two ultra-high stress strengthened ridgelines. This strengthening method not only improves the bending and compression resistance of hat section beam by 70% above, but also enhances its resistance durability of bending fracture by nearly 2 times. Obviously, it provides a great technology choice for designing some parts subjected to compressive and bending loads in vehicle body structure.