The effects of ultrasonic deep rolling (UDR) on the fatigue behavior of pre-corroded 7A52 aluminum alloys were investigated. By means of X-Ray diffraction stress measurements and scanning electron microscopy (SEM), residual stress and fractograph of 7A52 aluminum alloys with and without UDR treatment were analyzed. The results indicated that the UDR produced compressive residual stresses with depth approaching 1mm. UDR treatment can extend the fatigue life of the pre-corroded 7A52 specimens to a large extent, depending on the level of corrosion and UDR parameter. For the slightly corrode specimens, the UDR treatment changed the fatigue crack nucleation site from surface to the transition zone between the compressive residual stresses and tensile stresses, resulted in a much longer fatigue life. For the severely corrode specimens, the crack still nucleated by intergranular cracking, however, due to the compressive residual stresses introduced and the closure of the corrosion pits and corrosion micro-crocks, UDR treatment still improved fatigue performance of the pre-corroded 7A52 aluminum alloy substantially.
The Internet of Things (IOT) plays an important role in improving the equipment support capability. Using the Internet of Things, cloud computing and other new advanced information technologies, the equipment material support system is constructed. In this paper, the architecture, the network structure and building steps of the equipment material support internet of things system are designed to promote the development of equipment material support.
Digital binoculars is the combination of digital cameras and telescopes, it not only can observe the details of the long distance target but also can record it. The field of view between photographic field lens and telescope system is the same. This paper designs the telescope system on basis of the theory of dynamic optics. The system works in visual light waveband. The field of view is , the magnification is eight and the entrance pupil diameter is 32mm. prism is selected as the image rotation prism and image stabilization prism. In order to obtain clear images in a dynamic circumstance, we utilize the rotation theorem of prism to analyze the relation between jitter compensated lens and luminous beam angle. We can calculate the position of compensated lens. So it can achieve the jitter compensation. Finally, this paper takes an application as an example. If the jittered angle is , the displacement of pixel is calculated to 1.061mm. The displacement of the compensated lens is 2.84mm. At the same time, the light still arrives to the eyepiece by the original track. So image stabilization is relative to the reference coordinate, as a result we can get the stable image.
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