A HIGHLY CONSISTENT AND CONTROLLABLE COMBINED BLAST AND FRAGMENT LOADING SETUP

The combined effects of blast and fragment impacts on materials is an increasingly acknowledged area of study. The synergetic effects of a blast wave and the impacting fragments, the two main components of explosions, are usually recognized indirectly through the residual damage materials exhibit after being exposed within range of an explosive event. The increased complexity of an explosion sets a threshold to the level of detail and accuracy that can be applied justifying the former separation of the two fields: ballistics for fragmentation and structural engineering for the blast loads. In that regard, the response of materials to combined loads from explosions is largely an unsolved problem. In this study, a laboratory method for applying a synchronized arrival of a blast wave and an impacting fragment in a consistent and repeatable test is presented. In the proposed method, the blast wave overpressure and the fragment velocity are two independent variables that can be explicitly defined. These two components can be determined with a given explosive threat in mind. A third variable, the time interval between the two loads can also be selected based on the simulated stand-off distance of the explosive device from the target. For each combined blast and fragment impact loading test, the blast overpressure is measured with the use of pressure transducers. The fragment velocity is measured using a light-gate system and the time interval in between the arrival of the two loads is verified with the use of a high-speed camera. The level of accuracy and control of the proposed combined loading setup enables a more detailed investigation of the dynamic behavior of materials under the independent influence of Blast Overpressure, Fragment Velocity and Time of Arrival of the two loads.