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The interface between explosive crystal and binder polymer plays a critical role in the stabilities of energetic materials. In the present work, we investigate the mechanical properties of cyclotetramethylenetetranitramine (HMX)–polystyrene (PS) interface by performing molecular dynamics simulations of uniaxial tension, nanoindentation and nanoscratching tests. Our simulation results indicate that the HMX–PS interface has a mediate strength between HMX of high strength and PS of low strength. In particular for nanoindentation and nanoscratching, the distance of indentation position or scratching position to the HMX–PS interface has a strong influence on mechanical deformation behavior of HMX–PS system. Specifically, the HMX–PS interface has the lowest indentation force and scratching force than both the HMX and the PS. [ABSTRACT FROM AUTHOR]

In this paper the influence of vibration on reflectivity is systematically analyzed. A three-dimensional topography model of a machined surface considering vibration is established first. Based on the three-dimensional morphology model, the reflectivity of a diamond turned surface is calculated by a rigorous coupled wave method. The influences of cutting parameters on the diffraction effect of a diamond turned surface are discussed. The predicted and experimental results reveal that as the vibration intensifies with an increase in cutting depth and feed rate, the peak-valley (PV) roughness of the machined surface increases, which yields an increasing diffraction effect, i.e., resulting in a decrease in reflectivity. When the spindle speed is low, the tool and workpiece have a small sliding velocity, causing a great deal of friction, which amplifies the deformation of the workpiece surface. In this case, the PV value of the machined surface roughness is large, leading to a greater diffraction effect and bad reflectivity. With the increment of spindle rotation speed, the friction is relieved quickly, but the vibration is intensified, which produces increasing reflectivity. When the spindle speed is set to about 1200r/min, the reflectivity reaches the maximum value. When the spindle speed is larger than 1200r/min, the increase of vibration is dominant, resulting in a gradual increase in PV surface roughness and a decrease in reflectivity.

Spherical/aspherical mirrors are widely used in optical systems and imaging systems, but their reflectivity is affected by the surface roughness. In this study, the effects of plastic side flow and elastic recovery on the diffraction phenomenon and reflectivity are analyzed systematically. The energy ratio of an ultra-precision turning surface is calculated by rigorous coupled-wave method, the influence of aberration on diffraction efficiency is considered in combination with the specific structural parameters of spherical/aspherical surface, and the appropriate measuring beam diameter is selected. Through predicted results and experimental observations, it can be found that with the increase of plastic side flow height, the energy ratio of zero-order diffracted light reduces, the brightness weakens, and the diffraction light spots become more obvious. This is because large plastic side flow height leads to more complex three-dimensional surface topography and great roughness P-V value. The influence of elastic recovery on the reflectivity is different from that of plastic side flow. As the elastic recovery increases, the roughness P-V value lessens. As a result, the energy ratio of zero-order diffracted light enlarges, and the brightness strengthens. This paper provides a theoretical basis for machining of spherical/aspheric mirrors with high reflectivity.