Temperature distribution is localised in the thin cut edge s

Temperature distribution is localised in the thin cut-edge surface layer and the ptio coupling at the workpiece surface is important in terms of determining the cut-edge quality. Using high power intensity can therefore result in the beam being absorbed by the workpiece material, which can cause undesirable solid-state heating, melting and vaporisation of the workpiece material as well as workpiece distortion [21]. The key objective of this research is to find suitable laser process parameters to cut thousands of holes per square meter at a continuous operation to generate a perforated retrofit plate, as shown in Fig. 1. The array of holes provide weight saving of 45% and also, by introducing holes to vehicle armour, provide a protective advantage [22–24]. The perforated plate is a circular edge, rather than a hole, and when a projectile hits this edge it is deflected, which turns it from a sharp projectile into a blunt fragment; this makes it easier for the projectile to be stopped by vehicles with existing armour superstructure. Furthermore, the perforated armour also absorbs energy from land-based munitions across a greater surface area.
Experimental methods
Results and discussion
Conclusions
Acknowledgment
Introduction The infrared detection technology has been widely explored in the military domain, such as infrared precise guidance, search and tracking. With its continuous development, the spatial resolution of the infrared detectors is getting higher [1,2], and the infrared image generation models are getting more accurate [3,4]. Especially, along with the use of the human visual characteristics for detection, the infrared detection technology has achieved a remarkable development because the human vision has a selective attention property which is helpful to search the target from a complex background quickly and precisely [5,6]. The infrared target detection based on visual attention can be sorted into two types. One is that the saliency map is composed of individual feature maps, some of which are extracted from input image [7], and the other is that the saliency map is obtained via the statistical information of natural scene [8]. In other words, the infrared detection tends to be combined with the human vision image in the future, which induces the urgent requirement of the infrared defence of the object to be protected. As one of the effective defence technologies, the infrared false target has been extensively studied for decades, and the regulation of its surface temperature, the most important factor in the infrared defence, is increasingly stringent. From the aforementioned relevant introduction about infrared detection, bulbourethral glands can be expected that the only way to adapt to the future infrared defence challenges is to develop a false target having the same surface temperature and the same surface radiative properties (solar absorptance and infrared emissivity) as the object to be protected.
Model The object to be protected discussed here is reasonably assumed as a rectangular cabin, and the focus of exploration is the top cover of cabin which is the most important surface for the infrared defence. Because the top of the object to be protected is usually a metal plate, the goal of the work is to imitate a horizontal metal plate subjected to periodical ambient conditions. The one-dimensional heat transfer models of metal plate and imitative material, i.e., the featured surfaces of the object to be protected and the false target, were established to explore the influence of the difference of their thermophysical properties on the STD under the same periodical ambient conditions. Their top surfaces are exposed to the ambient environment, and the adiabatic boundary conditions are applied to their bottom surfaces from a practical consideration, as shown in Fig. 1. The possible application of metal plate and imitative material would be the surface cover of special equipment usually operating at high or low temperature (relative to the ambient temperature), which would form a strong thermal boundary condition for the bottoms of them. However, there is usually a thick thermal insulation layer around the equipment to make its operation stable. Considering the high-performance of thermal insulation layer, an adiabatic boundary condition over the bottoms of metal plate and imitative material can be a good approximation.