A sensitivity analysis framework for SMA-based self-centering systems considering uncertainty in hysteretic material parameters

Shape memory alloys (SMAs) are widely utilized as the core component to develop self-centering (SC) structures owing to their excellent super-elasticity. Seismic performance of SMA-based structures is significantly influenced by the hysteretic parameters of the exploited SMAs. Uncertainties in the hysteretic parameters of SMAs could cause variation in seismic performance however have not received sufficient attentions. This paper proposes a sensitivity analysis framework to realistically and efficiently quantify the sensitivity of SMA-based structures to hysteretic model parameters. The experimental data from SMA bars are analyzed through the Markov chain Monte Carlo (MCMC) procedure. The probabilistic distributions of SMA hysteretic parameters are then sampled using the linear moment theory. Polynomial chaos expansions (PCE) based surrogate model is then used to evaluate sensitivity of response to different parametric uncertainties through the Sobol indices. The proposed framework is then applied to a total of 120 single-degree-of-freedom (SDOF) systems to demonstrate its efficacy to generalize observations and findings. The results show that the proposed framework provided more effective and realistic sensitivity analysis of seismic responses of SMA-based SDOF systems to account for uncertainty in the hysteretic model parameters. The Sobol indices also indicate that the sensitivity of different seismic response quantities varies for different hysteretic model parameters of SMAs.