Simulation of Interactive Cyclic Local-Global Buckling in Steel Members Using Nonlocal Hybrid Element

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Computer simulations are essential for predicting how buildings and other infrastructure will perform under extreme situations such as earthquakes or hurricanes. Under such conditions, steel structures often collapse due to twisting and buckling of its parts (beams and columns). This type of failure is challenging to simulate in computer models, because current methods cannot represent the physical mechanisms of twisting and buckling or their interactions in an effective manner. This award supports fundamental research to create a method that represents the physics of these processes in a novel way, enabling more accurate simulation of structural failure under extreme loads. The findings and software technology from this research will enhance the resilience of buildings and other infrastructure, benefiting the nation's society and economy. The involvement of underrepresented groups, education of students with new knowledge, and technology transfer to practitioners will result in broader impacts. Steel members often fail under extreme loads due to interactions between twisting and buckling under cyclic loading that occurs in earthquakes. This process leads to loss in strength, ultimately leading to structural collapse. Currently used methods for modeling this process do not directly simulate the physical phenomena of warping, twisting and buckling, and are therefore severely compromised in terms of their accuracy in predicting failure. This research is a new scientific formulation in which the warping and twisting of members is represented in a novel manner. This formulation also allows for the incorporation of buckling through a 'nonlocal' approach such that results are not mesh-sensitive (meaning that they are objective). The scientific formulation will be implemented in an open-source numerical platform that is popular among structural engineers and researchers. This approach (including its implementation) will be informed and validated rigorously by extensive available experimental datasets and finite element simulation, and broadly disseminated to target audiences and user groups.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.