Mechanoluminescence of nylon under high velocity impact

18th APS-SCCM; 24th AIRAPT

Bonora, N.^1,2 ; Ruggiero, A.^1,2 ; Iannitti, G.^2 ; Abbate, C.^1 ; Iannuzzo, F.^1 ; Busatto, G.^1

University of Cassino and Southern Lazio, Cassino

I-03043, Italy^1

TECHDYN Engineering, Rome

I-00199, Italy^2

关键词: Deformation of solids;    Dynamic pressures;    High-velocity impact;    Hypervelocity impacts;    Impact velocities;    Infrared photodiode;    Mechanical action;    Uni-axial strains;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/500/18/182005/pdf
DOI  :  10.1088/1742-6596/500/18/182005

来源: IOP

【 摘 要 】

The light emissions produced during deformation of solids induced by any mechanical action is called mechanoluminescence (ML). This phenomenon was reported mostly in hypervelocity impacts. Using high speed video-recording, the authors found evidence of ML for nylon at much lower impact velocity (of the order of 100 m/s). In order to understand the mechanism responsible for ML, Taylor impact experiments were planned and performed. Several impact configurations were investigated: Taylor anvil impact, Taylor impact on nylon anvil and rod-on-rod impact experiment. During the tests, the emitted light was measured using a wide-spectrum visible-to-infrared photodiode with response below 1 microsecond, and the signals were analyzed. The existence of a limiting impact velocity below which ML is no longer observed seems to be indicative of the fact that ML is controlled by the high pressure that is generated under uniaxial strain loading conditions. This result is consistent with the fact that, as soon as the compressive stress wave travels longitudinally in the Taylor sample and the pressure drops as a result of the arrival of the release waves, the ML no longer occurs. When tests were repeated in vacuum, no light emission in the visible range was observed. This finding seems to indicate that light emission occurs as a result of the oxidation of free radicals generated by the rupture of the polymer chains caused by the dynamic pressure wave.