Hybrid simulation at Lehigh tests structural resilience In our second episode with NHERI Lehigh engineer Alia Amer, find out how this engineering lab performs real-time hybrid simulation, RTHS. This sophisticated, cost-effective testing method connects a numeric model of a substructure \u2014 with a physical model or device. Then researchers apply a natural hazard \u2013 wind, earthquake or waves \u2013 to test device resilience.