First Principles Estimation of Shock Tube Tests on Nanoreinforced Composite Materials

Abstract

Extreme loads events can cause enormous human and infrastructure losses. Computer modeling is the key to reducing the high cost of dynamic monitoring and experimentation. Engineers in various fields have undertaken complicated modeling for structures under abnormal loads. However, an efficient and accurate model is necessary to more rapidly address dangerous shock problems. Composite materials have replaced metals in various applications thanks to their superior shock resistance properties. This investigation particularly relates to their usage on naval ships to achieve improved blast survivability with the additional benefit of lower cost. A relatively simple model is detailed for the approximate centerline response prediction of the specific complex case of composite materials tested in a shock tube. A modal analysis simulation of a beam is performed using gross properties as well as physical geometry and arbitrary shock. Closed form equations have been employed to derive the eigenproblem that generates mode shapes and natural frequencies, and the resulting responses are compared to experimental shock tube test results. The best outcome was generated by the simplest model consisting of a shock pressure pulse averaged in two divisions and applied over the entire beam span. For this case, the simulation and experimental responses had reasonable correlation for fractured E-glass/vinyl-ester composite specimens with both nanoclay and graphite platelet reinforcement. This model is also a conservative estimate for the transient test deflection range for all other specimens.