7 The Influence of Formulation Variation and Thermal Boundary Conditions. . . 55 The reported transient surface temperature patterns appear to approach steady state over the 60 min window of harmonic excitation, resulting in temperature increases on the order of 0.5–1ıC, as expected from prior work with high solids loading composite materials [9]. The comparison of temperature profiles of different aluminum additive content plates yielded variations on the order of 0.5ıC, suggesting that increased additive content does not result in drastically increased heat generation at a forcing level of 2 g. However, the effect may be more evident as the forcing level is increased. The insulated boundary condition resulted in a temperature increase approximately 0.7ıC higher than the corresponding convective experiment in all of the plate formulations, as expected. However, the observed trends appear to be inconsistent with simple bulk-scale heat transfer models. Future efforts will investigate whether this is due to experimental error (i.e., measuring small temperature changes via an infrared camera), or, as is more likely, directly attributable to the particulate composite nature of the material. Thermal simulation of the heat generation within a sample of 85% solids loading with 0% additive content resulted in temperature increases significantly lower than experimentally-observed values. This also may be attributable to particleparticle interactions at the micro-scale, such as friction and de-bonding between the particle and the binder, which are not accounted for in the current heat generation model. Future work will seek to further characterize the particulate composite material with specific attention focused on particlescale interactions, increased excitation levels, and the impact of structural defects. Acknowledgements This research is supported by the Air Force Research Laboratory through Grant No. FA8651-16-D-0287 entitled “Hysteretic Heating of Polymer Crystal Composites through Mechanical Vibration”. The authors wish to acknowledge Jelena Paripovic and Professor Patricia Davies for their assistance with mechanical property measurements, and Jason Gabl and Professor Timothée Pourpoint for their assistance with thermal property measurements. References 1. Roberts, Z.A., Mares, J.O., Miller, J.K., Gunduz, I.E., Son, S.F., Rhoads, J.F.: Phase changes in embedded HMX in response to periodic mechancial excitation. Chall. Mech. Time Depend. Mater. 2, 79–86 (2017) 2. Paripovic, J., Davies, P.: A model identification technique to characterize the low frequency behaviour of surrogate explosive materials. J. Phys. Conf. Ser. 744(1), 012124 (2016) 3. Arefinia, R., Shojaei, A.: On the viscosity of composite suspensions of aluminum and ammonium perchlorate particles dispersed in hydroxyl terminated polybutadiene—new empirical model. J. Colloid Interface Sci. 299(2), 962–971 (2006) 4. Fu, S.Y., Feng, X.Q., Lauke, B., Mai, Y.W.: Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate–polymer composites. Compos. Part B: Eng. 39(6), 933–961 (2008) 5. Wakashima, K., Tsukamoto, H.: Mean-field micromechanics model and its application to the analysis of thermomechanical behaviour of composite materials. Mater. Sci. Eng. A146(1), 291–316 (1991) 6. Lewis, T.B., Nielsen, L.E.: Dynamic mechanical properties of particulate-filled composites. J. Appl. Polym. Sci. 14(6), 1449–1471 (1970) 7. Loginov, N.P., Muratov, S.M., Nazarov, N.K.: Initiation of explosion and kinetics of explosive decomposition under vibration. Combust. Explos. Shock Waves 12(3), 367–370 (1976) 8. Loginov, N.P.: Structural and physicochemical changes in RDX under vibration. Combus. Explos. Shock Waves 33(5), 598–604 (1997) 9. Miller, J.K., Woods, D.C., Rhoads, J.F.: Thermal and mechanical response of particulate composite plates under inertial excitation. J. Appl. Phys. 116(24), 244904 (2014) 10. Woods, D.C., Miller, J.K., Rhoads, J.F.: On the thermomechanical response of HTPB-based composite beams under near-resonant excitation. J. Vib. Acoust. 137(5), 054502 (2015) 11. Lochert, I.J., Dexter, R.M., Hamshere, B.L.: Evaluation of Australian RDX in PBXN-109. Technical report, Australian Government DSTO (2002) 12. Flueckiger, S., Zheng, Y., Pourpoint, T.: Transient plane source method for thermal property measurements of metal hydrides. In: The ASME 2008 Heat Transfer Summer Conference, Jacksonville, vol. 1, pp. 9–13 (2008) 13. Field, J.E., Bourne, N.K., Palmer, S.J.P., Walley, S.M., Sharma, J., Beard, B.C.: Hot-spot ignition mechanisms for explosives and propellants. Philos. Trans. R. Soc. Lond. A: Math. Phys. Eng. Sci. 339(1654), 269–283 (1992)
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