Microstructure-based modelling of spot weld failure in third generation advanced high strength steels

第三代先进高强度钢点焊失效的基于微观结构的建模

• 批准号: 549807-2019
• 负责人: Biro, Elliot
• 金额: $ 17.19万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=719577
• 关键词: Microstructure; based; modelling; spot; weld

To improve passenger safety and fuel economy, automotive companies have been integrating steels of increasing strength into the vehicle architecture. The newest materials of interest are third generation advanced high strength steels (3G AHSS) that have excellent forming and crash properties, but contain high carbon and alloying additions that create large variations in the mechanical properties within the weld zone. The structural integrity and crash performance of a 3G AHSS component is ultimately governed by these local heterogeneous properties that control the failure path and energy release. Since 3G AHSS have only recently become commercially available, there is insufficient knowledge of the constitutive and fracture properties of the critical sub-regions of the weld to accurately predict their behavior in full vehicle crash simulations. The considerable uncertainty surrounding the fracture behavior of 3G AHSS welds has led automotive companies to over-design 3G AHSS parts or to avoid their adoption.The proposed research will optimize the mechanical performance of resistance spot welds in two grades of 3G AHSS with ultimate tensile strengths (UTS) of 980 MPa and 1180 MPa, then develop a detailed understanding and predictive model of the failure behaviour during crash. This research will result in: (i) industrially-viable spot welding processes; (ii) a detailed characterization of weld microstructure and properties; (iii) an understanding of the mechanisms responsible for 3G AHSS spot weld failure; and (iv) the development of weld fracture models appropriate for industrial simulation, which will provide design tools for future generation lightweight automotive structures.The project outcomes will directly contribute to the competitiveness of the Canadian steel, parts, tooling, welding equipment and automotive manufacturers partnering on this project. Optimized welding parameters will be adopted into Canadian parts and assembly plants and the new simulation tools will be incorporated in automotive vehicle design and crash safety simulation, which will create market demand for these new steels.

为了提高乘客安全性和燃油经济性，汽车公司一直在将强度不断提高的钢材集成到车辆结构中。感兴趣的最新材料是第三代先进高强度钢（3G AHSS），其具有优异的成形和碰撞性能，但含有高碳和合金添加剂，这些添加剂在焊接区域内产生较大的机械性能变化。3G AHSS部件的结构完整性和碰撞性能最终由这些控制失效路径和能量释放的局部异质性质决定。由于3G AHSS最近才商业化，因此对焊缝关键子区域的本构和断裂特性的了解不足，无法准确预测其在整车碰撞模拟中的行为。围绕3G AHSS焊缝断裂行为的相当大的不确定性导致汽车公司过度设计3G AHSS部件或避免采用它们。拟议的研究将优化两个等级的3G AHSS的电阻点焊的机械性能，极限拉伸强度（UTS）为980 MPa和1180 MPa，然后对碰撞过程中的故障行为进行详细的了解和预测模型。这项研究将导致：（i）工业上可行的点焊工艺;（ii）焊缝微观结构和性能的详细表征;（iii）对3G AHSS点焊失效机制的理解;以及（iv）适合于工业模拟的焊接断裂模型的开发，该项目将为未来汽车轻量化结构提供设计工具。项目成果将直接有助于提高加拿大钢铁、零件、模具、焊接设备和汽车制造商在这个项目上合作。加拿大的零部件和装配厂将采用优化的焊接参数，新的模拟工具将被纳入汽车设计和碰撞安全模拟，这将为这些新钢材创造市场需求。