Theoretical And Experimental Study On Burst Point Control For Penetration Fuze

Fuze technologies for target penetrations can effectively enhance the damages generated on the targets, which has played an increasingly important role in the modern war. To be compatible and matched with the military penetration deployments, it is necessary for the fuze to have strong abilities of target identification and intelligent judgments. Therefore, the future penetration fuze should be developed towards the multi-function directions of precise timing counting, precise penetration trip counting, identification for the dexterity of the target structure, and intellectualization. Because the penetration ammunition fuze needs to withstand the high impact overload environment tests with small spatial dimensions, there are still some problems in the practical engineering applications with overload condition. Consequently, it is valuable and significant to carry out the research on key technologies of hard target penetration using smart fuze, which can contribute to improve the national defense capabilities. According to the application background of hard target penetration ammunition using fuze and requirements of high impact overload from the hard target penetration using fuze, reliability of high detonation and testability of fuze environmental information etc, the paper conducts some relevant research on the burst point control of hard target penetration using fuze, based on the current domestic and foreign penetration theories and technologies. The main work and research done are as follows:Based on the resistance force and conduct impact analysis on the motion state of projectile body in the penetration process, we conduct theoretical analysis of the hard target penetration process based on the spherical cavity expansion theory, analyze the velocity and acceleration of the projectile body and fuze system in the penetration process and the model of the penetration depth, and compare them with the measured data for analysis, which can provide a theoretical basis for buffer measures for hard target penetration, design of inertial switch withstanding high acceleration, research on the on-board test and measurement technology, and burst point control algorithms based on the comparison of acceleration amplitude.Secondly, construct the buffer model for the projectile body penetration process. In the penetration process, the fuze will be not only influenced the overload acceleration impacts, but also suffer from the structural vibration response impacts from projectile body. Therefore, the buffer protection for the fuze system is basic and important to realize the normal working. We install the nonmetal gasket on the mounting structure between the fuze and projectile body as the buffer structure, study its energy absorption characteristics, apply finite element simulation and test the buffer effects from the dynamic impact experiments. From those simulations and experiments, the nonmetal gasket demonstrates its good properties on the filtering and shaping effects for the stress wave and the reflection of stress wave at the junctions of different materials, and indicates the effective and obvious buffer effects. Additionally, it can make the fuze acceleration curve smooth simultaneously, which is suitable for external buffer protection functions for the fuze body.Because the hard target penetration fuze is applied for expensive penetrating ammunition, we propose to apply the inertial switches in the redundancy control of burst points to improve the reliability for the explosion. At the same time, build the dynamic motion model of inertial switch under the condition of high impact overload, and conduct the dynamic simulation. After summarizing the relationship between the trajectory of the mass and acceleration pulse under the condition of half-sine pulse acceleration signal, we design the inertial switch which can withstand the high g and percept the state of projectile body in the penetration process, and apply it to carry out the onboard signal acquisition tests for the redundancy control of fuze detonation.The fuze control circuit and the memory test circuit integrated design principles for hard target penetration fuze signal acquistion and performance monitoring. According to the property of one time penetration, we propose to apply the storage testing method triggered by the positive and negative delay respectively. As to this method, the channel one chooses the negative delay trigger mode, uses the change of the sampling signal as the trigger signal, and controls the sampling process by comparing the sampling values with the setting threshold. The second channel employs the positive delay triggered mode, and uses the launching movement of the firing mechanism as the triggered signal. Both analysis and experiments show that the combination of those two trigger modes can reduce the impacts from external interference signals to a maximal extent. And synchronize the data to store in the non-volatile memory at the same time in the date collection process, which can store the measured data in time even when the system is damaged in the penetration process inside an unpredictable and complex environment, so as to improve effectively the reliability of the one-time test and maximize the applicability for the system.Propose a variable gain control method for the output from piezoelectric acceleration sensor, which employs two-stage amplified mode in the signal conditioning circuits. We adopt a charge amplifier with fixed gain output in the first stage, and adjust the variable output gain for the operational amplifier in the second stage. And we can use the software to realize the control of the variable gain of the entire signal processing circuit in real time by sending the microprocessor instructions without changing any hardware circuit components. Such method demonstrates the large advantages for the practical applications in the sensor calibration, normalized signal processing and acquisition of signal with variable ranges.According to the complexity of the target structure and diversity demands of explosion position, we propose an adaptive control algorithm for fuze burst points in the hard target penetration process. The algorithm can guarantee obtaining optimal location for fuze burst points by setting the operating modes from multi-function modes, such as the touch explosion mode, time counting explosion mode, cavity identification explosion mode, target layer counting explosion mode, penetration trip calculating explosion mode, and fixed depth explosion mode and so on, before launching. Then, conclude the real time computing model of projectile trajectory based on the dual-axial accelerometer, and conduct simulation analysis by using finite element analysis software to validate the effectiveness of this model, which can demonstrate it can detect the real time changes of the attitude angles and the trajectory of the projectile body by using two dual-axis accelerometers, and provide enough information for the cavity recognition in the penetration process. In the following, use the prototype of fuze burst point control system to conduct the hard target penetration experiments and validate the effectiveness of fuze buffer measurements and reliability of the control system.The achievements of this paper provide experience and valuable references for both theoretical researches of hard target penetration and practical engineering applications, which lays the foundations for further engineering application studies.