Physics-based surrogate models of panels for portfolio analysis of transmission towers under hurricanes

Risk and resilience assessment of electric power networks requires estimating the structural response for thousands of structures at the regional scale. In particular, latticed transmission towers can entail large modelling and computational burden when high-fidelity finite element models are used. The lack of appropriate surrogate analytical models (or low-fidelity models) has hindered the efficient modelling of tower portfolios and, in turn, downstream research and applications. This paper presents an abstraction of panels as the basic components in transmission towers, defines the panel failure limit state and the engineering demand parameters for capturing the buckling failure mode, proposes physics-based surrogate models for panels, and develops a polynomial response surface metamodel for ensuring consistent simulation of panel capacity and demand. High-fidelity structural models serve for reference and validation. For the two common panel types (i.e. straight and inclined), the validation results show that the proposed surrogate beam-column element formulation offers good accuracy compared to the high-fidelity model. The proposed approach enables efficient panel-level finite element modelling of towers and panel-based tower failure analysis under hurricanes; for example, a pushover analysis takes only a few seconds. The presented surrogate models can facilitate the derivation of portfolio-oriented, parameterised fragility models for towers.