Thursday  |  Conference Center A  |  02:10 PM–02:30 PM

#13618, Novel Experimental Technique for Calibration of Cohesive Parameters

The adhesion strength of binder and explosive crystals in polymer-bonded energetic materials dictates the resulting mechanical properties of these materials under different loading conditions. In the current work, a miniaturized experimental setup capable of performing a peel test at different peel rates (10 nm/s-1 mm/s) and at constant peel angles (45º-135º) has been developed to experimentally quantify interfacial adhesion between soft elastomer and hard substrates. The peel tests were performed for various combinations of mock simulant (sugar) and binders (PDMS/ graphene reinforced PDMS) interfaces, and the adhesion energy was quantified. To aid the accurate calibration of the cohesive parameters for the crystal-binder interface, a novel experimental protocol in conjunction with a modified Mori-Tanaka model was developed. This novel experimental procedure involved the use of a soft lithography-based fabrication process to fabricate granular composites with a highly controllable 2D columnar model microstructure that allows for semi-analytical modeling of interfacial failure. This technique allows for the control of different aspects of the microstructure for a particular binder-crystal system such as size, morphology, and arrangement of crystals. The quasi-static mechanical response of these model granular composites was quantified using a custom-built micro-tensile experimental setup. Digital Image Correlation (DIC) was employed to measure the full-field kinematic and strain fields. The quasi-static tensile data for these 2D columnar granular composite specimens facilitated the calibration of the cohesive parameters for the crystal-binder interfaces.

Meena Kodali   Worcester Polytechnic Institute
Prajwal Bharadwaj   Worcester Polytechnic Institute
Nikhil Karanjgaokar   Worcester Polytechnic Institute