To solve the roll command singularity in end-game of bank-to-turn(BTT)for penetration guidance weapon,the formation principle of singularity and main influence factors of BTT-90 logic were analyzed based on the method of insensitivity analysis with partial derivative.The non-dimensional overload equation of guidance law was derived,and the simulation of actual trajectory was carried out.The regularity of the command varying with time was given,and it was proved that the singularity exists only in the stage of overload command exceeding zero.A singularity control strategy was designed,and the BTT control was divided into the normal zone and singularity zone,and the roll command smoothing method was used in singularity zone.The switch scheme was introduced.The simulation result shows that the strategy can eliminate the singularity existing in the BTT guidance and has few influence on the accuracy of guidance.

Research on the stress and strain of grain was carried out by change of grain’s inner hole diameter and the ratio of external diameter to inside diameter during the reliability tests of solid propellant grains. The material model of grain was based on incompressible viscoelastic constitutive relationship, and 3D finite element calculation model was established. The dynamic response of the grain’s stress and strain with different grain’s inner hole diameter and the ratio of external diameter to inside diameter was analyzed. The calculation results indicate that the stress and strain reached maximum at the brim of inner hole, and the maximum of stress and strain increased as the inner hole diameter and the ratio of external diameter to inside diameter increase.

To evaluate gun’s residual life accurately, relation between gun bore’s radial wear and reducing rate of interior ballistic performance was studied. The single section characteristic model was suggested by using the least square support vector machine method. The quantum behaved particle swarm optimization algorithm was introduced to carry out the model inverse analysis so as to determine optimal parameters. The single section model was weighted and averaged by taking the comprehensive effective degree as weighted coefficient; gun’s multisection residual life evaluation model was established finally. The real sample application analysis of 10 groups from service practice indicates that the prediction error of this model is 0.006%. The test results show that the model has high accuracy and practical value.

In order to improve muzzle velocity under a fixed maximum chamber pressure, a kind of structure of regenerative liquid propellant auxiliary chamber was designed. Taking account of the combustion process of droplets, an interior ballistic model was established. Numerical prediction was carried out based on 57 mm antiaircraft gun. The results indicate that the parameters, such as the location of auxiliary chamber, the total injection area, the length of injection orifices, the differential ratio and mass of injection piston, have remarkable effects on the interior ballistic performance. The “pressure plateau” can be achieved, and the muzzle velocity can increase significantly by optimizing these parameters.

The anti-penetration property of corrugated sandwich composite armor with the corrugation angle of 30°,45°,60° at different penetration angles was studied.Based on the jet energy loss,DOP and quality protection factor,the protection capability of different armors was studied.The energy absorption characteristics of different armors was analyzed.The reality of the simulation results was validated by experiments of 56 mm stander shaped charge penetrating the steel at 0° dip angle and jet penetrating the composite armor at 60° dip angle.The results show that the armor with 60° corrugation angle has the best protection capability; the 45° composite armor is the second; the 30°composite armor is the last.With the increase of corrugation angle,energy absorption of corrugated sandwich improves from 0.85 kJ to 1.58 kJ; energy absorption of rubber reduces from 1.42 kJ to 0.79 kJ.This kind of composite armor has excellent protection capability,and it can be used as a new kind of light armor.

In order to improve the convergence rate and precision of midcourse target tracking,an algorithm based on IMM(Interaction Multiple Model)-EKF(Extended Kalman Filter)was proposed.Based on the variation characteristic of acceleration of midcourse target,three-dimensional target-motion-model and measurements model were built by using velocity measured-value.A comparative analysis between IMM-EKF and traditional EKF was carried out.The simulation results show that IMM-EKF algorithm can improve the convergence rate of midcourse target tracking,and the tracking precision can also be improved by using velocity measured-value.The proposed filtering method has better tracking performance in midocurse,and it is effective.

Hybrid BTT/STT(Bank-to-Turn/Skid-to-Turn)control system applied to glide guided bomb(GGB)was studied.According to the dynamic characteristics and control demands of GGB,BTT control model was built,and the control structure was designed.The roll command dithers when the small overload command occurs in BTT control mode.To solve the problem,the Hybrid BTT/STT control mode was introduced.The six-degree-of-freedom(6DOF)trajectory simulation of BTT/STT and full BTT control mode was carried out.The result shows that the hybrid BTT/STT is valid and effective.The achievement offers reference for the design of BTT control system of GGB.

According to the characteristics of the region antiaircraft problem,the application of particle swarm optimization to weapon-target allocation problem was studied.A logic of interception feasibility determination was represented from the point of distribution control condition,the fight time,the relative distance between fire unit and target.A particle coding scheme based on the interception feasibility constraint was proposed,which reduced the solution searching space of the allocation problem.The population evolution update scheme was also designed to enhance the diversity of the population,which improved the solving efficiency.Simulation results demonstrate that the algorithm has more powerful global-search-capability and higher convergence velocity for solving the region antiaircraft weapon-target allocation.

In order to explore the long-cycle problem of recoil mechanism’s structure design resulted from that the nominal dimension and tolerance can’t be optimized simultaneously,an improved interval optimization method considering tolerance was proposed to optimize the key structure dimension of the gun recoil-mechanism.The tolerance was assumed to follow normal distribution,and the discretization-based possibility degree model of interval was established,then the tolerance index was improved.The interval optimization model of the key structure parameters of the gun recoil mechanism considering tolerance was developed.Compared with the traditional structural parameters optimization results of gun recoil-mechanism,the key dimensions of the system were optimized,and the design cycle of the gun recoil-mechanism was shortened.The result shows that the Pareto optimum-solution of better objective-performance can be obtained by applying discretization-based interval-possibility-degree model,and the improved tolerance index can reflect the relation of average tolerance and machining precision.

Muzzle vibration is the key factor influencing the firing accuracy for tank firing on the move.In order to reduce the muzzle vibration at the time of the projectile passing muzzle,a dynamic model considering multiple nonlinear-factor of multi-body system for rigid-flexible coupling tank on the move was established based on the rigid-flexible coupling and the contact impact arithmetic theories of multi-body dynamics.Combined with the optimum design theory,the muzzle vibration optimization model was established.Radial Basis Functions(RBF)and Augmented Lagrange Multiplier Method(ALMM)were used to solve the multi-objective optimization function for muzzle vibration.The optimization result shows that the muzzle vibration of projectile can be effectively reduced.The proposed optimization method is feasible,and it offers reference for improving the firing accuracy for tank on the move.By changing the speed and the road grade,the what-if analysis shows the necessity of the optimization for tank firing on the move.

To obtain the real time calculation of attack area, considering engine’s ignition, driving delay of rudder and other factors, a mathematic model of computing attack area with limited condition was built. The golden section method was used to find out near attack area and far attack area, and the case of large difference of elevation was analyzed in detail. The attack area function was obtained by curve fitting. Far boundary of attack area is mainly decided by the height of fighter under the conditions of large difference of elevation. The test result has little error, and the proposed method is effective.

To make the flight vehicle track the curved trajectory precisely, a 3D nonlinear guidance command with output of accelleration was designed. The point on scheme trajectory was chosen as the reference point. Using the position coordinate and velocity of flight vehicle, nonlinear overload guidance command by which the flight vehicle tracked the curved trajectory was proposed. The method of choosing reference point was analyzed in aspect of time domain. The simulation result shows that the guidance order can make the guided projectile track the trajectory precisely.

To decrease the high temperature of concentric canister launcher in the launching process of missile, the water chamber was designed at the bottom of concentric canister launcher. The water was injected at the launching moment or some time before the launching moment. The water vaporized and absorbed heat, and then the temperature can be decreased. The water vaporization was considered, and the Mixture multiphase was used to solve the gas liquid flow field. The zone moving and dynamic laying was used to update the meshes. The different water mass conditions were simulated. The 15 kg computational result was compared with the simulation results of the standard and ejecting concentric canister launchers. The concentric canister launcher with 15 kg water can decrease the missile temperature and keep the missile at a low temperature in the whole launching process. The cooling effect of wet concentric canister launcher is preferable.

The correction components of 2D trajectory correction projectile(TCP)with fixed-canard have different roll-angular velocities relative to the body,and 6D trajectory model can’t effectively describe the motion characteristics of the projectile.To solve this problem,the projectile was treated as two rigid bodies.Under the assumption that the front component and the aft component have no pneumatic coupling,new coordinate frames were built,and mathematical relationship between the force of the fixed component and airflow by redefining attacking angle and side slip angle was described.The relations of the movement of projectile,the correction component and the body component were studied.The interactive force between two rigid bodies during flight was analyzed.The 7D ballistic model was built through integrating kinematic equations and dynamic equations.Aiming at one fin-stability shell,the simulation model was built,and the simulation was carried out.The results show that this model can describe the motion state in the flight and reflect the trajectory characteristics.This model can be used for ballistic solution,and it provides reference for studying the projectile.

In order to improve the accuracy of high-speed spinning projectile and to supply more precise base data for compiling firing tables and designing control systems for guided projectile,the analysis of identifiability for aerodynamic parameters in theory was carried out.Based on Genetic Algorithm-Maximum Likelihood Estimation(GA-MSE),the drag coefficients of spinning projectile were identified by using radar data of velocity.The accuracy and reliability of GA-MSE were validated by using simulated data.The actual data was processed by using GA-MSE,and a satisfied result was obtained.The result of simulation experiment data and actual experiment data were analyzed.The result shows that GA-MSE has high precision for parameter identification.

The aerodynamic performance of waverider missile was analyzed by the design of experiment (DOE) and CFD. Based on the CFD results, the aerodynamic response model of waverider missile was established. The effects of initial trajectory conditions and engine thrust upon periodic skipping trajectory performance were analyzed in detail. The optimization model of skipping trajectory was established based on trajectory analysis, and the skipping trajectory was optimized by using multiobjective particle swarm optimization(MOPSO)algorithm. The results show that trajectory performance and flight path are affected mainly by the initial trajectory conditions. Based on the demand of trajectory performance indices, it is feasible to obtain the optimal scheme trajectory by using MOPSO algorithm.

Based on the principle of independence of cavity section expansion, software was given to calculate the shape time variation characteristic of supercavity. The cavity length changes within 5%, and the maximun radius variety doesn’t exceed 2% in rough wave. The cavity dimension decreases with the increase of navigation depth. A part of cavity collapses rapidly when the pressure impulse is large enough, and other cavity retains close to the cavitator, and the cavity shape can hardly be kept. The effect of ocean wave on the supercavity of underwater vehicle is little. The cavity dimension should be noticed to ensure that the vehicle is not wetted while depth changing. The supercavitating flow can be destroyed by explosion shock.

In order to obtain the best pressure detection point of delay arming device of underwater rocket, the pressure distribution of projectile was calculated by numerical simulation in 42 cases. Considering the effect of factors such as water depth and angle of attack, a method of selecting the best pressure detection point was proposed. Based on simulation results, the optimal pressure detection point was gained by calculation. The results show that the optimized scheme has high theoretical precision, and the theoretical dispersion of arming distance is within -6.5%~6.5%, which can meet actual needs. The method of using underwater trajectory pressure environment to achieve delay arming is feasible, and it offers important reference for designing delay arming device of underwater rocket fuze.

In order to solve the ignition problem in charge design of large caliber gun with high muzzle energy, the experimental research on multi point ignition technology in long chamber charge was carried out. The structure of ignition tube and the simulation device of multi point ignition tube were designed. Different pt curves in different length were measured. The experimental result was analyzed. The ignition system, which includes igniters, black powder bag, snake shaped black powder bag and combustible central tube, has characters of short ignition time and good consistency. The ignition system can satisfy the need of charge design of large caliber gun with high muzzle energy.

Taking the reentry gliding vehicle as study object, the trajectory linearization control(TLC)structure for hypersonic gliding vehicle was put forward based on trajectory linearization observer. To satisfy the requirement of high performance and strong robustness for hypersonic gliding vehicle, considering the uncertainties such as measurement errors during flight, a state observer was designed for the outer/inner loop respectively by trajectory linearization method based on the hypothesis of outer loop and inner loop. The closed loop of TLC controller/observer is exponentially stable. Simulation results under hypersonic flight conditions verify the excellent performance and robustness of the proposed method. The state observer improves the performance of the controller and reduces the requirement of operator.

The influence of layout of nozzle and jet pressure ratio on aerodynamic characteristics of hybrid extended range projectile(HERP)with jet from its nose was researched by the wind tunnel experiment.Experimental Mach number was 2.0,2.5 and 3.0; angle of attack range was from 0 to 6°; jet pressure ratio range was from 0 to 180; media of jet was cool air.Layout of nozzle included 3 types of the inclined angle of nozzle and the number of nozzles.The experimental results show that the drag coefficient decreases(except for individual condition); the lift coefficient increases; the center of pressure moves downstream markedly.The drag coefficient of HERP decreases as the inclined angle of nozzle and the number of nozzles increases.The increase of the lift coefficient and the downward movement of pressure center are greatest as the inclined angle of nozzle is 30° and the number of nozzles is four.The influence on the lift coefficient and the center of pressure of the inclined angle of nozzle and the number of nozzles is basically the same in other conditions.The drag coefficient decreases,and the change of the lift coefficient and the center of pressure is unmarked with the increase of jet pressure ratio.

To obtain characteristics of space-time for external ballistic meteorological elements exactly,the theory of monadic linear regression and multiple linear regression was applied,and the regulation of meteorological elements varying with time,longitude,latitude and sea level elevation was studied based on the research and technical specifications of external ballistic meteorological elements.The formula model for external ballistic meteorological elements was established,and the characteristics of space-time meteorological elements in Tibetan plateau was obtained through meteorological data.

Aiming at gun erosion caused by periodic transient-thermal-shock during succession firing,the mathematical model of one-dimensional transient-heat-transfer of gun barrel was established.The finite difference equations of internal nodes and boundary nodes were derived by using energy balance method and ADI(Alternating Difference Implicit)scheme.Based on the numerical results of the classical interior ballistics,the temperature distribution of barrel of some 12.7 mm machine gun during 120 succession firing rounds was calculated numerically by Visual Basic programming.The temperature test was conducted by thermal infrared imager.The error of the numerical result relative to the experimental result is less than 10%,and the established model and the used algorithm are effective.The obtained change law of barrel temperature-field has great importance for the further studies of gun barrel erosion mechanism,and the result provides the reliable theory basis for the structure design and the life prediction of gun barrel.

Ballistics is one of the foundational disciplines in weapons science and technology,closely related to the development of weapons technology. With the rise and development of intelligent projectiles and rockets,the theory and technology of intelligent ballistics will be a major direction for the future development of exterior ballistics. Nevertheless,how to understand the concept,connotation,and functions of intelligent ballistics,as well as its differences from existing projectiles and rockets in terms of flight trajectories,the key technologies it relies on,the challenges involved,and the issues that should be considered for the subsequent development,are still under discussion. Based on the theory and technology of exterior ballistics and focusing on the future development of exterior ballistics,this article tends to analyze and organize the aforementioned issues with the aim of providing assistance for the future development of intelligent ballistics theory and technology. It should be noted that the development of intelligent ballistics theory and technology has introduced numerous new problems,concepts,terminologies and technologies for exterior ballistics,which require continuous exploration,refinement,and gradual perfection by researchers in the field of exterior ballistics through ongoing research. This article merely serves as a starting point,hoping to inspire more researchers in the field of exterior ballistics to engage in this area of study and gradually develop a theoretical framework.

To investigate the side cavitation phenomenon occurring around submerged vehicle at large attack angle,the mathematical model and numerical methods for cavitating flow based on the transportequation typed cavitation model and non linear eddy viscosity turbulence model were established.A computer code for the computation of complicated three dimensional cavitating flow was developed.The cavitating flow around submerged vehicle was numerically simulated.The computed cavity shapes are consistent with experimental ones,and the side cavitation phenomenon,which was observed in experiments on submerged vehicle with large attack angle,was successfully simulated.The velocity distribution on cross section and the pressure distribution on vehicle surface,were quantitatively analyzed.The result shows that under the conditions of large attack angle,the enough component of lateral velocity can bring about the sharp increase of cavitation area while the attack angle increasing to a certain extent.

To study ignition delay of base bleed propellant grain affected by ignition jet, aiming at the process and characteristics of re ignition of a 155 mm base bleed projectile, the numerical simulation of two phase flow ignition of base bleed igniter was conducted based on a kind of two phase ignition model and some hypothesises. The soften time and delay time of ignition were obtained by numerical calculation. The radial temperature distribution of base bleed propellant grain was given before combustion. The changing cases of soften time and delay time of ignition were analyzed due to the changes of the temperature of ignition jet, volume concentration of particle phase and diameter of particle. The study results offer reference for improvement of igniter and base bleed propellant grain.

The threshold velocity of energetic foragment with different case materials was theoretically analyzed. Aiming at energetic fragment with different material, different ratio of length to diameter and different shell thickness, the threshold velocities were got by using LSDYNA. The experssion including diameter of fregment, head shape and the materials of target and shell was established. The trend of impact initiation of energetic fragment with different structures and different materials was analyzed by experiment. The results show that the ratio of length to diameter of fragment and shell material affect the initiation threshold velocity. While designing the energetic fragement, it is beneficial to increase the ratio of length to diameter and choose the material with high density and high performance.

To study the effects of drag force reduction by low temperature plasma, the experiment about low temperature plasma actuating panel on the surface of NACA 0015 air foil was carried out by means of a low speed wind tunnel. The drag reduction performance of low temperature plasma was obtained. The experimental data indicate that low temperature plasma can effectively suppress boundary layer separation, and the flow drag force can be reduced under certain conditions. The effect of low temperature plasma reducing flow drag force is linear to the voltage and frequency of loaded power.

The astringency and real-time character of Newton iterative method are connected with initial iterative value in the magnetic survey solution of high-speed rotating ammunition,and the convergence is slow and even divergency appears.The GA was applied to quickly search the approximate solution,and the solution was taken as initial iterative value.Taking high-speed rotating ammunition as an example,the attitude angles were solved using the proposed method,and the algorithm errors such as fixed attitude angle data error,initial fixed parameters error and magnetic measured data error were analyzed.The results show that the GA-Newton iterative method can effectively improve the convergence and rapidity.When a given attitude angle error is less than 5° and magnetic data error is less than 500nT or initial geomagnetic component error is less than 1000nT,the attitude angle error is less than 3°,and the algorithm has higher precision.

To design a new composite rod penetrator,the penetration characterizatic of tungsten carbide long-rod normally penetrating into semi-infinite steel targets at the impact velocity from 800 m/s to 1 400 m/s was researched.The numerical simulations corresponding with the experiments were performed by customizing-strength constitutive-model coupled in AUTODYN finite element code.Both the penetration depth and crater shape calculated by the simulations are in good agreement with the experimental results.Further analyses of the penetration process of tungsten carbide long-rod normally penetrating into semi-infinite steel targets were carried out.The change rules of the rod-mass and penetration depth with the penetration time at different impact velocities were obtained.The result shows that the consumed rod-mass relative to penetration depth of the low-velocity tungsten-carbide rod is less than that of the high-velocity rod.The analysis results provide a basis for the design of the composite rod penetrator.

In order to study the high-aspect-ratio axial-symmetrical aerodynamic configuration of small ammunition,the lift-drag characteristics of the aerodynamic configuration and the force on elastic wing were obtained by mathematical simulation and wind tunnel test.Taking into account the effect of the elastic wing on the aerodynamic load,the effects of the wing turning over 5° and 10° on the whole spring resistance were analyzed.Aiming at the characteristics of the folding wing assembly,the impact of the deployable mechanism on the aerodynamic characteristics of the projectile was analyzed.The results show that the effect of the wing turning over on the lift force is great,and the effect on drag force can be neglected.The non synchronization of missile wing has little influence on the aerodynamic characteristics of the whole missile.Based on the operational mission of the small unmanned aerial vehicle,the use of the high-aspect-ratio axial-symmetrical aerodynamic configuration on the UAV ammunition was proposed.

Euler angle method is often used to describe the scanning of single fin terminal sensing ammunition. There are too many trigonometric calculations which bring about singular points and transmission errors. Aiming at this problem, quaternion method was used to represent the Euler kinematics equation, and modify the system’s differential equations. Compared with the traditional Euler angle method in describing the scanning of single fin terminal sensing ammunition, the computer simulation results show that the quaternion method is more conducive to the calculation, and also suitable for all kinds of posturing scanning motion, and therefore is more objective and accurate to reveal its scanning laws.

Aiming at the rotating speed measurement of rotating projectile, the radar cross section(RCS) and rotating speed of projectile with slot at the bottom were analyzed, and the formula for finding rotating speed was proposed. The modern spectral estimation of the state space direct data approximation(DDA)was adopted to estimate the spectrum of echo signals instead of general fast Fourier transform(FFT)arithmetic. The simulation and test were carried out to evaluate the spectral estimation of this new proposed arithmetic under different signal to noise ratio. The relation graph of measurement errors and signal to noise ratio was given. Compared with FFT arithmetic, the method evidently improves the precision of speed measurement.

To evaluate the kill probability of terminal guided projectile(TGP), the target equivalent model was established, and the kill criterions of the fragment and the shock wave against target were obtained according to the structural characters of position radar. Single shot kill probability of TGP was set up by using Monte Carlo method. The influences of terminal ballistic parameters on kill probability were analyzed. The results show that the kill probability of single shot TGP can improve effectively by increasing falling angle, and the influence of explosion height on kill probability is concerned with falling angle. The study result is helpful to TGP design.

In order to analyze the influence of SEFAE device structure on damage power, center dispersed and center with circumjacent dispersed SEFAE devices were designed based on explosion characteristics. The static explosion experiments were carried out, and the SEFAE damage power parameters were measured by high speed photograph and wall pressure transducers. The experiment results show that: the apt inner shell with the optimized SEFAE device structure can increase the utilization rate of SEFAE total energy and the far field overpressure, so as to improve the damage power; the center and circumjacent dispersed SEFAE with steel inner shell is the best device with 30 m fireball diameter, and its average TNT equivalent and the maximum TNT equivalent at 14 m were 2.19 and 3.17 respectively.

To analyze the feasibility of muzzle brake applied to mortar, the calculation method of noise elimination was derived based on micro pore muffler theory, and then the structure of a muzzle brake of mortar was presented by using the noise elimination theory of expansion micro pore muffler. The analysis indicates that the noise at distance 1 m from the mortar muzzle in the direction perpendicular to the airflow is reduced by 21.7 dB with the muzzle brake on the mortar. By sloving the differential equation of projectile motion in aftereffect period, the muzzle disturbance in gas ejection period was acquired for the mortar with and without the muzzle brake, and the result shows that the muzzle brake is beneficial to improving shoot precision of the mortar.

The composite laminated barrel has a bad heat dissipating performance, and its firing rate is limited. To solve the problem, the segment enwound technology was applied to composite barrel. Based on a special firing criterion, numerical simulation and experimental study on temperature field of segment enwound composite gun barrel were carried out, and the results were compared with the composite laminated barrel. The calculated peak value of composite material temperature is 313.4 ℃, which is lower than the work temperature of composite material. The segment enwound technology can effectively solve the limitation of composite laminated barrel, so it has a good prospect for engineering application.

To evaluate blasting damage effect of fiber reinforced warhead, the blast effects of three charges, i.e.naked charge, charge with composite material shell, and charge with steel shell, were studied by means of experiments. Experimental results show that peak overpressure caused by detonation of explosive charge with carbon fiber composite shell is higher than that of charge with steel shell, but lower than that of naked charge with the same quantity of charge. No fragments that are of danger to distant targets are generated in charge with carbon fiber composite shell. Charge with steel shell has results of striking contrast. According to the blast effect on the concrete target, charging with composite material shell is superior to that with steel shell in matched impedance as well as detonation propagation. Under the same explosive charge conditions, the effective energy produced by the detonation of explosive with composite material shell is stronger than the one with steel shell.

In order to study the properties of plasma jet ignition,two-dimensional-axisymmetric unsteady compressible mathematical model for plasma jet propagation in air was developed,and the software Fluent was used to simulate this process.The variation law of the interface between plasma jet and air was obtained as well as the distributions of static pressure,temperature and velocity of the plasma jet flow-filed.The analysis results indicate that:there occurs strong turbulent mixing between plasma jet and air;the mixing intensity increases along the downward flow-field gradually.There is a standing shock wave at 9.2 mm in front of the nozzle,and the parameters of plasma jet behind the shock wave vary nonmonotonically with time.The pressure,temperature and velocity have the trend of attenuation along the axial direction and radial direction as a whole.The distributions of temperature,pressure,etc,fluctuate spatially.The displacement of plasma jet obtained by simulation agrees with that obtained by experiment well.