Tornado-borne debris impact performance of an innovative storm safe room system protected by a carbon fiber reinforced hybrid polymeric-matrix composite

A new tornado safe room design is proposed using a recently developed Carbon-fiber reinforced Hybrid Matrix Composite (CHMC), or “CarbonFlex,” to withstand tornado-borne debris impacts. Test results reveal that the new CarbonFlex wall panel has superior impact resistance in comparison to conventional residential construction and some alternative residential tornado-resistant wall panel constructions observed in the literature and identified in the current work. Two CarbonFlex design groups successfully passed the high-debris impact tests at a missile speed of 44.7 m/s (100 mph), corresponding to a ground wind speed tornado of 111.7 m/s (250 mph) while the two other CarbonFlex wall panel designs passed tests at missile speeds of 40.2 m/s (90 mph), corresponding to ground wind speed tornados of 89.4 m/s (200 mph). Additionally, a control group wall panel design that was manufactured using a conventional carbon fiber reinforced polymer (CFRP), or more precisely a carbon fiber reinforced epoxy, indisputably failed two debris missile high-impact tests. The material processing parameters of CarbonFlex, i.e., the matrix thickness, hp, and an intermittent curing time, tc, show to be evidently influential on the impact resistance capability of the CarbonFlex panels where the resistance generally increases with smaller values of tc and with greater values of hp. The merits of using CarbonFlex over conventional building envelop components are quantified via vulnerability assessments of both conventional and the newly developed composite wall panel system under tornado transported debris impacts.