Potential-of-Mean-Force Approach for Molecular Dynamics-Based Resilience Assessment of Structures

A molecular dynamics (MD)-based structural mechanics approach is proposed for the assessment of resilience of buildings. At the core of the approach, potentials of mean force (PMFs) suitable for structural members for both two-body (stretch) and three-body (bending) interactions are derived to define the energy states between mass points discretizing structural members. An original potential parameter calibration procedure is proposed: for close-to-equilibrium potential parameters, the procedure is based on matching measured frequency of a structure with the frequency of the molecular model. In turn, for bond-rupture parameters, it is shown that classical interatomic potential expressions, such as Morse potential, can be used to calibrate the energy content of many structural members and connections. By way of example, the MD-based structural mechanics approach is applied to a large-scale structure. Compared with classical continuum-based approaches, the added value of the method thus proposed is a rational means of determining the progressive structural collapse load of structures based on thermodynamic integration. By redefining structural mechanics within the context of statistical physics, molecular simulations, and potentials of mean force, the approach provides a powerful means of determining fragility curves required for the assessment of resilience of buildings.