Attenuation Law Based On The Reflection Type Photoelectric Tachometer And A Fragment Velocity

Using the prefabricated fragment as origin of stimulate is one of the significant test methods. Measuring the speed of fragment accurately and safely offers significant ground for the safety evaluation of explosive. In this paper, the method of velocity measurement and the regularity of the velocity-attenuation according to the flying feature of the fragment is studied.The system of photoelectric velocity measurement based on reflection which based on the technical indexes and the flying features of fragment is developed. In this paper, the schemes that the optical system and the signal sampling system should be integrated and the optical signal forms the sector detecting screen of light by adverse reflection is proposed. The system has the features that, the safe distance is far, the effective detection area is large, the response speed is high and the anti-interference ability is strong through the lectotype design of the light source and the photoelectric converter, the buffer design of rang pole, and the multiple amplification & comparison design of the circuit.By combined with technical indexes, the each technical index and the whole performance of the system is verified by using the methods of simulating calibration and the correlative experiment in this paper. The results show that the system has some practical value.In order to get the regularity of the fragment velocity attenuation so as to predict the fragment speed, the test system of the regularity of the fragment velocity attenuation and carries out the experiment of the firing practice is established, which obtains the experimental data of time and displacement of the fragment movement.And in this paper the experiment data is processed by the quadratic equation method and the middle-point-speed method. At the same time, the paper analysis and compares the error of the two methods is analyzed and compared, and a conclusion is drawed that the fitting effect and the standard deviation at each point of the quadratic equation method is better than the middle-point-speed method's. Therefore, the experiment data is processed by the quadratic equation method, which obtains the initial speed & the attenuation coefficient of the taper fragment, and the regularity of the fragment velocity attenuation is got.