Numerical and Physical Experiments on Sugar Pearls as a Means of Studying Brittle Material Crushing and HE Pressing

It is known that void sizes and distributions significantly affect many important properties, such as detonation, sensitivity, and safety of a high explosive (HE) material. In this work, we wish to engineer void size distributions in pressed HE charges for the purpose of dialing HE sensitivity properties. However, the connection between pre-pressed powder structure and pressed void structure is complex and insufficiently understood. Motivated by the fact that sucrose is a good HE mechanical mock, we wish to better understand this connection by using hard candy products as a surrogate for brittle HE powders.

Sugar pearls are compacted both in numerical simulations and physical experiments. The numerical method used is the Dual Domain Material Point (DDMP) method. The method is chosen to accurately represent the complex pearl packings, large deformation of the pearls, and their breakage. The numerical results are compared to experimental results at the grain, meso, and macroscopic scales. At the grain scale, we compare the force displacement relations. At the meso scale, we compare pressing results of a few hundred pearls for their positions and damages obtained from the X-ray tomography of the samples. At the macroscopic level, we compare the density-pressure relations.