The Materials for Extreme Environments (MEE) team has over a decade of experience developing, enhancing, and employing two-stage light gas guns (2SLGGs). In addition to the 12.7-bore 2SLGG located at the Texas A&M University Hypervelocity Impact Laboratory (HVIL), the Materials for Extreme Environments team, under the direction of Prof. Thomas Lacy, established two 2SLGGs at Mississippi State University (MSU). The countless lessons learned in creating these previous laboratories informed and motivated design and procedural enhancements over the years that led to an overall increase in testing reliability, efficiency, and safety. Our team prides ourselves in our ability to not only institute cutting-edge facilities but also create a culture of innovation that leads to perpetual novel improvements in testing and diagnostic capabilities.
The first 2SLGG, small scale (up to 1 mm diameter projectiles) compared to the HVIL 2SLGG, enabled a variety of research, including studying the effects of shear-thickening-fluid-filled honeycomb composites on hypervelocity impact (HVI) performance. The gun was capable of launching smaller projectiles to velocities ranging from 2-8 km/s. The lessons learned from this 2SLGG in part motivated the design of the second 2SLGG.
The second 2SLGG was much larger with a maximum projectile diameter of 4 mm. This gun could launch such projectiles to velocities exceeding 7 km/s. It is evident that the design of this 2SLGG is a slightly different, smaller scale version of the HVIL 2SLGG. The target tank is quite similar, with the 45 and 90 deg windows being the main difference. Like before, the lessons learned from operating this 2SLGG led to design changes for the HVIL 2SLGG, including larger launching capabilities, more sophisticated (pneumatic) valves, more diagnostic windows and through ports, a larger blast tank, digital pressure transducers, and a comprehensive control panel. The desire for a larger launch capability (6.35 mm bore to 12.7 mm bore) led to a 30% increase in the length of the HVIL 2SLGG compared to the MSU 2SLGG.