Beyond Numerical Convenience - A Critical Evaluation of Damping Paradigms for MDOF Systems

Abstract

Precise damping characterization continues to be a formidable and poorly resolved issue in the seismic evaluation of multi-degree-of-freedom (MDOF) systems. Although vital for capturing energy dissipation, damping is frequently relegated to oversimplified mathematical assumptions that fail to track actual physical mechanisms, especially as systems enter nonlinear regimes. This research executes a rigorous appraisal of structural dynamics damping models, tracing the evolution from standard proportional Rayleigh formulations to sophisticated non-classical, hysteretic, and fractional frameworks. By situating these models within a cohesive theoretical envelope, we dissect their numerical execution and physical fidelity.

 This analysis demonstrates that the computational ease of classical models and their neat fit with modal analysis often comes at the cost of significant artifacts. These include spurious force generation, frequency-dependent biases, and distorted energy dissipation profiles in both elastic and inelastic contexts. We systematically quantify how these modeling choices ripple through critical engineering demand parameters, with specific focus on nonlinear time-history simulations and soil–structure interaction. The resulting comparative data suggests that no universal model exists; instead, selection must be dictated by specific structural behaviors and analytical goals. Finally, we map out urgent research frontiers, emphasizing the shift toward physically consistent formulations, seamless nonlinear integration, and the nascent role of data-driven uncertainty quantification in refining performance-based seismic design.