In order to explore the influence of impact crushing phenomenon of propellant grains during the Cased Telescoped Ammunition(CTA)firing process, the difference and inconsistency of gunpowder grain is ignored, and a new theoretical approach related to the shape of gunpowder is proposed. According to the impact and crushing mechanism of energetic gunpowder, the grain impact crushing process is simulated by using the changes in gunpowder shape parameters. This grain fragmentation model is applied in the simulation of the one-dimensional and two-phase flow simulation of the CTA. The effect of grain fracture on the ballistic performance of the CTA during the ignition process can be predicted, which will improve the unique charge structure and ignition theoretical basis of the CTA and also enhance the launching safety. By comparing the simulation results of simulated gunpowder particles without fragmentation and breakage, it is found that under the abnormal ignition of the CTA, partial crushing grains in the chamber during firing will cause the surge of crushing stress, and the maximum value increases from 25.7MPa to 35.1MPa, with an increase of 36.6%. The proportion of gunpowder combustion surface increases significantly, the degree of fragmentation reaches as high as 5.8. Meanwhile, the breech pressure increases sharply, and the maximum chamber bottom pressure and the maximum bullet bottom pressure is 1.069 times and 1.047 times respectively compared with the normal structure. The high-amplitude and choppy pressure waves are easily generated,and the maximum negative peak of the pressure wave decreases from -2.6MPa to -11.0MPa. The gas-solid two-phase movement in the bore is more complex and changeable, and the muzzle velocity increases from 1146m/s to 1163m/s.

In order to solve the problem of high chamber pressure of oblate spherical propellant containing high-energy solids at low-temperature, and to avoid the reduction of propellant energy, spherical double-base propellants with nitrate glycerol ether cellulose(NGEC)were prepared. The effects of NGEC on the shape, combustion performance, interior ballistic performance and sensitivity of oblate spherical propellant were investigated. The results showed that the uniformity of shape and size of spherical propellant granules were good after adding NGEC. The combustion of propellants presented progressive burning, and the impact sensitivity decreased by 30%. The interior ballistic performance was improved. At +15, +50 and -40℃, the average maximum bore pressure decreased by 10%, 8% and 15%. The low-temperature(-40℃)mechanical properties were improved, when the fragmentation rate was kept at 50%, and the high impact and impact resistance strength increased by 10.52% and 17.32%. NGEC is expected to be applied to spherical double-base spherical propellants.

To estimate the interior ballistic performance of gun propellant charge, a calculation method was established using static burning parameters obtained by the closed-bomb tests. The calculation of interior ballistic performance of charge was performed using 5/7 single-base camphor gun propellants from different batches, and the 30mm gun tests were carried out to evaluate the calculation accuracy. The results show that the calculated maximum chamber pressure by this method is 376.0MPa. Compared with mean value of tested maximum chamber pressure of 388.7MPa, the calculated error of the maximum chamber pressure is 3.27%. The calculated muzzle velocity is 1143.5m/s, with the calculation error of 1.11% compared with the tested velocity result of 1156.3m/s. The calculation method with high precision is effective on estimating the interior ballistic performance of propellants from different batches. It also provides a new method for assessment of propellant storage and service life. At last, it can serve as an economical and effective evaluation method in the delivery inspection.

The domestic and overseas technical advance about reducing ballistic temperature coefficient of gun propellant charge, including surface compensation technic such as mechanical flattening technology, coating technology, surface coated double base (SCDB) technology, extruded impregnated (EI) technology, extruded composite low sensitivity (ECL) technology and so on, were reviewed. The burning rate of low temperature coefficient (LTC) gun propellant can be kept basically consistent at different temperatures by optimizing its configuration, resulting in decreased ballistic temperature coefficient of gun propellant charge. Electrothermal-chemical launch technology can reduce ballistic temperature coefficient of gun propellant charge significantly by adjusting input energy to compensate the decrement of burning rate of gun propellant. Combined with the basic principle of reducing ballistic temperature coefficient of gun propellant charge, the regulatory mechanism of reducing ballistic temperature coefficient of gun propellant charge by using different technological approaches is summarized. Based on the above discussion, the researches on ECL gun propellant and SCDB gun propellant should be carried out in the future. And the research on the interaction mechanism of plasma and gun propellant and the study on the miniaturization of power supply should be further strengthened with 62 references.

Aiming at the deflection problem of oblique penetration of the projectile, the calculation model of warhead penetration into multil-layer concrete trajectory was established. The penetration ballistic trajectory and ballistic parameters in the range of attack angle of -4°-4° and impact angle of 0°-30° were calculated. The influence factors of the penetration trajectory of concrete trajectory were studied. The influence law of attack angle and impact angle on ballistic deflection is discussed. Through penetration experiment of multil-layer traget, the correctness of calculation model was verified. The results show that the attack angle and impact angle make ballistic occur deflection, when the ballistic deflection caused by attack angle is opposite to the deflection direction caused by the impact angle, the deflection of the penetration trajectory will be suppressed.When the two cause the same deflection in the direction, the deflection of ballistic will be intensified. When the attack angle is opposite to the direction of the impact angle, if the magnitude of impact angle and attack angle meets the relationship of 5-10 times, it can make the displacement of ballistic trajectory reach the minimum under the impact angle condition.

The desire for increased performance from guns is driving the charge designer towards charges that present challenges to numerical modelling. There is a pressing need for accurate, validated ignition and combustion models that can be used to predict the performance of advanced charges and ensure pressure waves are not developed or, if they are, then they can be managed. This paper describes efforts to model complex charge designs using a two-dimensional axi-symmetric multi-phase flow internal ballistics model.

The change rule of burning rate and pressure exponent of the propellant in the range of 6-20MPa was studied taking a kind of middle or high burning rate CMDB propellant as basic formula and adding Al₂O₃ with different particle size and different kinds of internal ballistics stabilizer.The combustion mechanism was analyzed. The results show that the burning rate decreases when Al₂O₃ is added. The reduction range of burning rate reduces with the pressure rising. The range of enhancement or reduction of different kinds of internal ballistics stabilizer to burning rate and pressure exponent is different. TiO₂ increases the burning rate in high pressure stage and MgO does not affect the burning rate of propellant while Al₂O₃and ZrO₂ both decrease the burning rate of propellant. The catalyst content (or concentration) on the combustion surface decreases when different particle size of Al₂O₃is added. The catalytic efficiency of catalyst is changed, which leads to 0.5mm/s and 1.25mm/s reduction on burning rate of propellant added aromatic lead A andAl₂O₃ with the particle size of 10μm and 2.5μm, respectively. The influence of internal ballistics stabilizer on catalyst content, dispersal uniformity and catalyst activity is different. The activity of TiO₂ and MgO is higher than that added Al₂O₃and ZrO₂, which reflects that the burning rate of propellant added TiO2 or MgO is higher than that added Al₂O₃and ZrO_2.

To overcome the weak robustness,hypersensitive to initial values and dependence on theory ballistics equation of existing ballistics fusion algorithms,it was proved that the global maximum point of Gaussian kernel density estimation(KDE)function constructed on limited samples is an unbiased estimator of expected value(EV)of Gaussian distribution which above samples obeys,and a method based on tracking the global maximum point of KDE function was proposed by researching the probability distribution of measurement error. The Gaussian KDE function was built on all measurement data,and thus the essence of ballistics fusion was turned into calculating the global maximum point of Gaussian KDE function. To avoid the time-consuming process in classic iterative method,a tracking algorithm was proposed,which samples many neighbors of the global maximum point through shifting previous result,employs Taylor estimation method to obtain many potential results and selects the result corresponding to the global maxima of Gaussian KDE function. The theoretical analysis and calculation indicate that the tracking algorithm is effective and can be implemented with lower time-consuming by comparing with classic iterative method. The method was compared with optimization method,spline restraint and unscented Kalman filter by experiment.The experimental results show that this method performs higher accuracy,stronger robustness,easier extensibility and higher smoothness in noise-tolerate capability test,sensitivity test for initial values,flexibility test and stability test,and it can be implemented in real-time application.

To solve the problem of optimal ascent trajectory design in case of small thrust-weight ratio of launch vehicle’s last stage,and send payloads into orbit with much less velocity loss and propellant consuming,a new trajectory design method based on more accurate line-gravity field was proposed by simplifying yaw program angle and co-states,which transfered the optimal thrust direction in vacuum flight into a two-point boundary value problem containing five constraints,and got the optimal trajectory by integrating motion equations. Furthermore,the initial values of iteration were analyzed according to launch vehicle’s flight features,and an estimation method of initial values of co-states and flight time was deduced,and a means and process of launch vehicle trajectory design in whole ascent flight based on linear-gravity field was put forward. The simulations show that this method generates the same results with the conventional method in situation of normal thrust-weight ratio,and pitch program angle varies nearly linearly. In situation of small thrust-weight ratio,this method generates much less velocity loss,saving 2.9% and 2.1% propellant compared with the conventional method and iterative guidance respectively,and pitch program angle varies non-linearly. This method is of good convergence and optimization effect,and can be well applied in trajectory design of small thrust-weight ratio and launch vehicle’s whole ascent flight. This method can also supply a new means of online trajectory planning,etc.

The design of trajectory in boost phase of the lift vehicle is facing the difficult problem of carrying capacity optimization under the coupling condition of multiple constraints in the complex atmospheric flight environment. It is necessary to design the program angle of the boost phase to maximize speed of entering orbit under the constraints of stages separation height,angle of attack limit,height of the orbit entry point,etc. In order to find an engineering design method to quickly solve this problem,taking the three-stage solid launch vehicle as the research object,the multi-constraint trajectory design method in boost phase of the lift vehicle was put forward. The design variables were formulated by designing the flight trajectory mode of the boost phase,and the constraint conditions of the boost phase were determined. The optimization model aiming at the maximum orbital speed under multi constraints was built. By analyzing the coupling relationship between design variables and constraints,an efficient optimization process was formulated. The optimization initial value was determined by Newton iterative method,and the optimization simulation was carried out by sequential quadratic programming method. The optimal solution satisfies the multi-constraint conditions,and the orbit entry speed increases by 3.1%,which verifies the correctness of the trajectory design method and the effectiveness of the optimization process. The multi-constraint trajectory optimization design method in boost phase of lift vehicle has strong engineering practicability. The modeling method and optimization process can offer reference for other optimization problems.

The traditional L1 penalty sequential convex programming algorithm(LPSCP)has a large linear approximation error in trajectory programming of guided projectiles,which leads to the trembling of the objective function curve,and it is difficult to converge to the optimal solution. Aiming at this problem,an improved L1 penalty sequential convex programming algorithm(ILPSCP)was proposed. The ILPSCP algorithm introduces the relative trust region width of exponential attenuation and the penalty coefficient with upper bound to eliminate the tremor of the objective function. Taking the generalized control energy optimal trajectory programming model as the research object,the Radau pseudo-spectral method was used to discretize the continuous variables and linearly convex the nonlinear dynamic equation to establish the standard convex optimization model. Taking the gliding trajectory model of the guided projectile in the longitudinal plane as an example,the traditional LPSCP algorithm,the proposed ILPSCP algorithm and the general nonlinear optimization toolbox GPOPS2 were used to simulate and compare. The simulation results show that the ILPSCP algorithm successfully solves the problems of chatter and instability of the traditional LPSCP algorithm. At the same time,the simulation results of the ILPSCP algorithm are highly consistent with those of the GPOPS2,which proves the effectiveness of the proposed algorithm in solving complex trajectory programming problems.

In order to optimize the shape design of the projectile head,reduce the impact of head erosion on ballistic deflection during penetration,and then improve the ballistic stability of the projectile oblique penetration into multi-layer targets,a composite penetrator was designed. The ballistic deflection of the composite penetrator penetrating three-layer spaced steel target at the velocity of 500-800 m/s was calculated by ANSYS/LS-DYNA. The ballistic offset of the composite penetrator and the integral penetrator was compared,and the influence mechanism of the cap material on the trajectory of the composite penetrator was discussed. Experimental verification was carried out. The results show that in the velocity range of 500-800 m/s,the penetration of each layer and the final ballistic offset of the composite penetrator are significantly smaller than those of the integral penetrator. With the penetration velocity increasing from 500 m/s to 800 m/s,the ballistic stability increases by 54%,50%,60% and 32% respectively. At the penetration speed of 500 m/s,the total ballistic offset of 35CrMnSiA cap composite penetrator is slightly less than that of 93WNiFe cap composite penetrator. When the speed increases to 800 m/s,the final ballistic offset of 93WNiFe cap composite penetrator is less than that of 35CrMnSiA cap composite penetrator.

In order to satisfy the development needs of multistage piston cylinder launching equipment(MPCLE),multiple air-bottle power producer,time-sequence of multiple solenoid valve,the interior ballistics model of MPCLE was established,and the testing program used for the model verification was designed. The simulation and experiment study on the interior ballistics was carried out. A structure design scheme of MPCLE was described. Referencing the classical zero-dimension interior ballistics model for guns,an interior ballistics model was established according to the working principle of the launching equipment. The launching testing program for the 3 000 kg bob-weight was designed. In order to verify the correctness of the interior ballistics model,the launching equipment of MPCLE and the parameters of the interior ballistics were measured in the experiment. The peculiarity of the interior ballistics was discussed,and matters needing attention of the pipeline system and the valve were provided. The calculated curve was compared with the measured curve. The result shows that the calculated result agrees closely with the experimental result,and the interior ballistics model can satisfy the development needs of MPCLE. The interior ballistics model can be used to determine the air-bottle initial pressure and the time sequence of multiple solenoid valve for the specific launching assignment,and the model can be used to the development of MPCLE.

In order to solve the practical problems of unknown and time-varying measurement noise statistics in real-time trajectory filtering,the algorithm of improved Sage-Husa adaptive Kalman filter(ISHAKF)was proposed based on the improvements of Sage-Husa Kalman filter algorithm. By converting the covariance estimation matrix of measurement noise into sum of a positive semi-definite matrix and a positive definite matrix,the algorithm ensures the positive definiteness of the measurement noise covariance estimation matrix. Thus,the defect of abnormal filtering caused by non-positive definite covariance estimation matrix of measurement noise can be eliminated. An adaptive forgetting factor was designed,which improved the filter convergence speed and overcomed the problem of the slow convergence speed of Sage-Husa algorithm when measurement noise statistics were abrupt. The robustness of Kalman gain matrix was improved to increase the robust performance of the algorithm and weaken the influence of outliers on the filtering effect. Then,comparative simulation experiments were carried out on the improvements of positive definiteness,forgetting factor and robustness separately. The comparison results verify the correctness and effectiveness of improved Sage-Husa algorithm. Through the example application of ISHAKF algorithm,it is proved that the real-time performance,adaptability and robustness of ISHAKF algorithm are better in real-time trajectory filtering. Also,the filtering effect of the algorithm is obviously promoted.

Aiming at the poor impact point accuracy and low strike accuracy of traditional mortar shell,the trajectory correction algorithm of mortar shell was designed. The trajectory was corrected by perturbation impact point deviation prediction method,adaptive proportional guidance method and adaptive proportional differential guidance method. The six degree of freedom trajectory model and control model were established,and the perturbation impact point deviation prediction method and proportional guidance method were proposed. In view of the fact that the constant proportional coefficient of proportional guidance law does not conform to the actual trajectory change,the adaptive proportional guidance law was designed in the longitudinal plane,and the adaptive proportional differential guidance law was designed in the transverse plane. Monte-Carlo simulation was used to verify the correction ability of guidance law in longitudinal plane,transverse plane and compound guidance. The simulation results show that the adaptive proportional navigation law was the best in the longitudinal plane,and the adaptive proportional differential navigation law was the best in the transverse plane. The composite guidance effect of three guidance methods was simulated and analyzed. The simulation results show that the composite guidance and correction ability of perturbed impact-point deviation prediction guidance method in the longitudinal plane of ascending arc,adaptive proportional guidance law in the longitudinal plane of descending arc and adaptive proportional differential guidance law in the transverse plane,were effectively improved,and the circular probable error of impact points of mortar was reduced from 126.317 m to 0.965 5 m. Under the conditions of large shooting angle and small range,the circular probable error is 1.864 3 m.

The research on the aerodynamic characteristics of the two-dimensional trajectory correction projectile is the foundation of solving the trajectory of the two-dimensional trajectory correction projectile and analyzing the flight stability of the two-dimensional trajectory correction projectile,and it is the theoretical support to achieve precise control and reduce dispersion. The mechanical characteristics of two-dimensional trajectory correction projectile were analyzed,and the engineering calculation method of the aerodynamic characteristics of the wing assembly was adopted. The aerodynamic calculation model of two-dimensional trajectory correction projectile was established,and the lift force and drag force of two-dimensional trajectory correction projectile were calculated. Comparing the calculated results with the CFD simulation results,the error is less than 10%,and the model has good reliability. Combined with aerodynamic calculation model of two-dimensional trajectory correction projectile,the influence of rudder deflection angle and roll angle on the lift-drag ratio of two-dimensional trajectory correction projectile was analyzed by using genetic algorithm. The results show that the smaller the rudder deflection angle,the greater the optimal lift-to-drag ratio of the whole projectile,the greater the optimal angle of attack,and the better the aerodynamic capability. When the angle of attack is greater than 10° and the roll angle is 180°,the full projectile has better aerodynamic capabilities.

In order to obtain the dispersion law of impact points and the evaluation method of firing accuracy for a certain type of trajectory correction projectile,lots of impact-point data of trajectory correction projectile was obtained through the Monte-Carlo target practice. The distribution law of impact points was analyzed by using classical numerical statistics,histogram,probability paper,skewness kurtosis testing and SPSS software. It was determined that the dispersion of impact points obeys the two-dimensional normal distribution,and the probability density function was also obtained. The firing accuracy of the trajectory correction projectile was compared with that of uncontrolled projectile. The result shows that the index and calculation method of uncontrolled projectile are suitable for evaluating the firing accuracy of trajectory correction projectile. It provides theoretical and technical support for the acceptance of firing accuracy of trajectory correction projectile,and it’s also helpful for the application of the ammunition in future war.

In order to improve the intelligent level of robot,further study on robot navigation was carried out. The ballistic curve was applied to robot navigation control. The Beidou navigation of humanoid robot ballistic-curve channel was researched,and the ballistic curve channel model and the humanoid robot ballistic-curve channel Beidou navigation model were established. The navigation algorithm of Beidou navigation model of the humanoid robot ballistic-curve channel was put forward,and Beidou navigation system of the humanoid robot ballistic-curve navigation channel was studied. Beidou navigation control principle of the humanoid robot ballistic-curve channel was described. It was verified by simulation and experiment. The results show that the proposed ballistic-curve channel model,Beidou navigation model of the humanoid robot ballistic curve channel are reasonable. The system can realize humanoid robot ballistic-curve channel Beidou navigation and further improve the intelligent level of humanoid robots.

In order to study the properties of launching interior ballistics of missile launching system,a simulation model of thermal-fluid coupling flow field for imbedded launching power system was established by Fluent software. The dynamic mesh method was used to simulate the motion process of missile in the launching cylinder. The energy utilization coefficient of missile launching process was obtained by thermal-fluid coupled calculation between flow field and solid walls of launching system. The simulation results of interior ballistics are in good agreement with the experimental results,and the heat dissipation caused by launching power system is about 1/4 of that caused by launching cylinder. The simulation model can offer reference for subsequent simulation,and the energy coefficients computed can provide basis for the prediction calculation of launching interior ballistics.

To solve the deficiency of accumulated errors of trajectory data measured by inertial navigation neasurement system,inertial-navigation-measurement trajectory correction model based on optimal fuzzy system was constructed. The input-output data pairs constructed by trajectory telemetry data and high-precision GNSS data were applied to design fuzzy system. Taking high-precision GNSS trajectory data and inertial navigation measurement data of missile flight test as learning objectives and sample trains models,the fuzzy rule base of inertial navigation measurement data correction was established by nearest neighbor clustering method. Taking inertial altitude correction as example,the effectiveness of the method was verified,and the external trajectory processing data of the missing paragraphs of optical measurement and GNSS measurement were completed,and the accumulated error of inertial navigation measurement trajectory data with time was corrected.

In order to study the penetration performance of 93W tungsten alloy fragments into 616 armor steel,the ballistic limit velocity of cubic fragments(with square bottom)and cylindrical fragments were tested by ballistic gun tests,and the theoretical formula was modified by the test results. The modified formula can be used to predict the ballistic limit velocity of fragments. The simulation results were compared with the test results to verify the reliability of the materials. The regression equation was established according to the initial velocity and residual velocity of the fragments. The ballistic limit velocity of the fragments was obtained by extrapolating the regression equation obtained. The influence of the dimensionless projectile length(DPL)and the dimensionless target thickness(DTT)on the ballistic limit velocity was further studied. The results show that when the materials of fragments and target plates are determined,the ballistic limit velocity is only related to DPL and DPL. When DPL and DTT are determined,the influence of fragment shape on the ballistic limit velocity is obvious,and cubic fragments are easier to penetrate the target plates. When the DTT is 1.6,the ballistic limit velocity increases with the increase of DPL of the fragment when vertically penetrating the target plate with thickness of 12 mm. The ballistic limit velocity of the fragment increases about 45 m/s for every 0.1 increase of DPL value. When the DPL is 1.0,and the ballistic limit velocity increases with the increase of the DTT when vertically penetrating targets with different thickness. The ballistic limit velocity of the fragments increases about 50 m/s for every 0.1 increase of the DTT.

In order to maintain a better aerodynamic shape of the guided projectile in different flight states,improve the flight efficiency and increase the range,a morphing guided projectile was designed. The aerodynamic parameters calculation,aerodynamic characteristics analysis,ballistic simulation were carried out. Firstly,the aerodynamic layout of the morphing guided projectile was determined according to the design parameters,and the specific shape parameters of the wing,canard and tail fin of projectile were determined through iterative optimization,the control modes and ballistic characteristics of the morphing guided projectile were described. Then the aerodynamic data of the morphing guided projectile was calculated by using engineering algorithms,the relationship between lift coefficient,drag coefficient,static stability and the change of the projectile wing shape was analyzed. Finally,a morphing scheme was developed for the designed morphing guided projectile based on the results of aerodynamic characteristics analysis. Hp-adaptive pseudo-spectrum method was used to optimize the ballistics of the morphing guided projectile and the fixed-profile guided projectile with the goal of maximum range. The results show that the designed morphing guided projectile meets the design parameters and has good aerodynamic characteristics and maneuverability,and the ballistic calculation results show that the range can be increased by 10% to 22.5% by introducing the morphing flight technology.

A reciprocating gliding extended range trajectory scheme was proposed to extend the effective range of subsonic cruise missile. The models of horizontal cruise trajectory and reciprocating glide cruise trajectory were established based on the existing aerodynamic parameters. The effective range and characteristics of the two trajectory schemes were compared and analyzed. The principle of extended range of reciprocating glide trajectory was studied from the conservation of energy. The influence of initial flight Mach number,initial trajectory inclination angle and initial flight altitude on the range extension characteristics of reciprocating glide trajectory was further studied. The results show that the reciprocating glide trajectory can effectively extend the range,and the efficiency of extending range of the reciprocating glide trajectory reaches 100.42% compared with the maximum flight distance of the conventional horizontal direct-flight trajectory. On the premise of the realization of the reciprocating gliding trajectory,the greater the initial flight Mach number,the smaller the initial trajectory inclination angle and the lower the initial flight altitude,the more obvious the extending range efficiency of the reciprocating glide trajectory.

To overcome the inaccuracy,instability,lack of robustness and reference standards faults of artificial external-ballistics selection performed in real-time rocket launching,and improve the accuracy and efficiency of decision-making in control center,the coordinate transform theory and classical dynamics theory were applied,and the association models between the telemetry angle and the velocity,the apparent acceleration and the external acceleration in which the relationship between telemetry information and exterior ballistic information was established,were constructed respectively. A selection method of external ballistics based on telemetry information was proposed. Taking the theoretical trajectory and theoretical telemetry data of a rocket as data input,the correlation models between telemetry angle and external velocity,telemetry apparent acceleration and external acceleration were simulated and verified. The simulation results show that the error of the correlation model is very small,which verifies the correctness of the correlation model. Finally,taking the actual measured exterior ballistic data and telemetry parameter information of the rocket as the input,an optimal trajectory was obtained by using the trajectory optimization method. And then these trajectories including the optimal trajectory result were compared with the high-precision post-processing trajectory. The comparison results show that the comprehensive error of the optimal trajectory is the smallest,which verifies the effectiveness and correctness of the optimal method. By the external ballistics optimization method based on telemetry information,the correlation model between telemetry information and exterior ballistics information can be correctly established,and the exterior ballistics with high accuracy can be selected. Thus,the method provides more auxiliary decision-making means for trajectory optimization in control center,and has strong theoretical application value.

When shooters have an unconscious habit of shooting sideways or require to operate the gun face sideways for shooting due to the constraints of the terrain environment at the time of the mission,the aiming line will remain unchanged,and the muzzle will deflect around the aiming line. It will lead to the change of the spatial position of the muzzle to take the aiming line as the reference and thereby lead to the deflection of the impact point due to the change of the vertical and horizontal surfaces of the ballistics. In order to determine the mounting method of the scope while the gun face tilting sideways,a 7.62 mm high-precision sniper rifle were taken as the research object,and the spatial modeling function of the 3D design software was used,and the firing data coordinate system was established. The geometric method was used to analyze the influence of the muzzle tilt on the external ballistics and the distribution law of the point-of-impact deviation,and the formula for calculating the point-of-impact deviation was deduced while the gun face tilting sideways. Besides,the ballistic correction method was studied,and the set of equations for calculating the ballistic correction amount was proposed,and the precautions and training points for the shooter were pointed out. A test of point-of-impact deviation and ballistic correction was designed and conducted when the gun face tilted sideways at a 100 m shooting distance,and the results were analyzed. The study provides a ballistic calibration reference for a type of 7.62 mm high-precision sniper rifle to be used in combat shooting while the gun face tilting sideways,and it also provides a new test method for measuring projectile deflection flow.

To obtain the ballistic characteristics of supercavitation projectiles during underwater parallel launching,the underwater processes of synchronous and asynchronous parallel projectiles were simulated based on overset mesh,RANS equation,k-ε turbulence model and Schnerr-Sauer cavitation model. By setting different projectile spacing and launching time interval,the flow field characteristics and ballistic characteristics of underwater parallel supercavitation projectiles were compared and analyzed. The result shows that for underwater synchronous launching,the development of cavitation inside the projectile is inhibited,and the projectile deflects outwards under asymmetric hydrodynamic action. When the projectile spacing increases to be greater than 4D,there is almost no interference between the two projectiles. For asynchronous launch projectile,the offset of projectile increases first and then decreases with the increase of launch time interval. For the projectile launched after asynchronous launching,with the increase of launch time interval,the inhibitory effect of lateral cavitation expansion is gradually relieved,and there is a tendency of excessive expansion. The longer the time interval is,the slower the velocity attenuation is.

In order to study the complex interaction of the final trajectory parameters and the lethal area to optimize the final trajectory parameters,the fragment dispersion process was analyzed,and the fragment dispersion model was established to calculate the effective fragments on the ground. The lethal area of the warhead under different final trajectory parameters was solved by counting the number of effective fragments on the ground. The lethal area under 1 225 final trajectory combinations was obtained. On this basis,the extreme learning machine(ELM)was used to optimize the calculation of 1 903 993 final trajectory combinations. The results show that the determination coefficient can reach more than 0.9,and the solution time is much less than 1 s,and the lethal area increases from 438.1 m² to 541.2 m² when the number of hidden nodes is more than 200 and the sigmoid function is used to the extreme learning machine.

In order to accurately characterize the fragment trajectory,the movement equation of the fragment was established based on the mass-point trajectory equation and the resistance formula of classic fragment. The external ballistic characteristics of the steel fragment and the tungsten fragment under typical working conditions were calculated and analyzed. The results show that the shooting angle corresponding to the maximum range of fragments is about 21°. With the increase of the initial shooting angle of fragments,the kinetic energy of fragments on the ground decreases sharply first,and then showly increases after about 10°. By applying the two calculation forms of parabola and ray,the landing kinetic energy and maximum fire range of typical fragments under the conditions of different initial shooting angles were analyzed. The proposed method has a certain reference value for the maximum kill-radius and damage effectiveness evaluation of fragments,the rationality of layout position in the dynamic and static detonation test range of explosive warhead,and the judgment of storage safety-distance of ammunition.

In order to improve the lightweight of cased telescoped ammunition(CTA)and the energy utilization rate in the launch process,the combustible cartridge materials were applied to the structure of cased telescoped ammunition(CTA). Based on the secondary ignition and propellant combustion technology,the combustible cartridge was simplified into a variable burning-rate flake charge,and regarded as one of the mixed charges,and the zero-dimensional interior ballistic model of CTA with semi-combustible cartridge was established. Numerical simulation of 105 mm CTA grenade shooting experiment was carried out,and the correctness of the proposed model was verified. On this basis,the interior ballistic performance of 105 mm CTA armor-piercing projectile with semi-combustible cartridge was predicted and analyzed. The maximum chamber pressure is 537.5 MPa,and the muzzle velocity is 1 667 m/s.

Aiming at the internal ballistic optimization of solid rocket motor,the range of uncontrolled rocket projectile was taken as optimization objective,and the mathematical models of single-push and double-push internal ballistics were established respectively under the conditions of constant total impulse. An improved hybrid particle swarm optimization(HPSO)algorithm was proposed to optimize the internal ballistics,and the global optimal solution was obtained. Simulation results show that the proposed HPSO algorithm has strong searching ability and robustness,and the algorithm is an effective method to deal with the internal ballistic optimization of solid rocket motor. The proposed optimization strategy increases the range of the 122 mm uncontrolled rocket projectile by 3.75%-4.45%. The methods and conclusions are available for the design of uncontrolled rocket.

The spike installed on the blunt-nosed body pushes the strong bow shock away from the body surface in supersonic speed,which forms recirculation flow with low pressure ahead of the body surface,and then decreases the drag,and the landing velocity of the rocket can be increased. Aiming at this problem,the effect of the spikes shape parameters on the drag induction and its flow mechanism were simulated. Based on the aerodynamic-ballistic coupling method,the spikes shape parameters were optimized to increase the landing velocity. The results show that the additional drag of the spikes is larger,and there is no drag reduction in subsonic speed and transonic speed. The drag reduction of the spikes is remakable in supersonic speed,and the optimal shape lengths increases,and the radius decreases with the increase of the Mach number. Based on the coupling method considering the effect of the drag aerodynamic of the spikes on the ballistics,the landing velocity and the range after optimization can be increased by 10.0% compared with the initial shape. In the calculation range,the effect of the spikes is little on the lift characteristic and the static stability.

The trajectory correction method based on the perturbation theory of impact-point prediction has the advantages of high accuracy and small amount of calculation. A series of problems related to the application of the perturbation theory to the impact-point prediction in the two-dimensional trajectory correction were studied. Based on the Taylor series expansion theory of multivariate functions,a complete theoretical model for impact-point prediction was derived. Based on the perturbation deviation theory,a modified step-size adaptive method was proposed to solve the shooting angle data quickly. Generally,the firing angle data can be obtained by solving the ballistic model in a cycle no more than 3 times,whose fall-point error is no more than 1 m. Based on the average trajectory error of different trajectory positions,the setting method of trajectory deviation in partial derivative solution was given. The proposed method of dynamic trajectory deviation correction threshold can reduce 29.1% of trajectory correction times without increasing CEP.

To further study the influence of secondary combustion on the interior ballistics,the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations and renormalization group turbulent model were applied to numerically study the gas-ejection process. The tailor motion was simulated by dynamic mesh method. The simulation results were compared with the experimental results. The result shows that the parameters of secondary combustion interior ballistics are more similar with the experimental values. The numerical simulation results show that the contact surface between gas and air is smooth in multicomponent case,however,the contact surface is plicate in secondary combustion case. The oxygen mass fraction in the initial chamber plots indicates that the secondary combustion phenomenon occurs within 0.2 s after the gas generation working. Influenced by the secondary combustion,the acceleration of secondary combustion case is higher than multicomponent case at the start time,but lower at the following time. The secondary-combustion phenomenon advances the out-tube-time of aircraft and decreases the out-tube-velocity of aircraft.

To study the angle of yaw,and velocity deflection angle characteristics of high-rotation two-dimension trajectory correction projectile after canards control,an angular motion equation was established by applying the control assembly to provide the control force and torque on the basis of angle motion of uncontrolled projectile. The acting laws of the action of initial disturbance,instantaneous control force and long-time control force onthe angle of yaw and velocity deflection angle were analyzed. Numerical calculations show that when the high-rotation two-dimension trajectory correction projectile is subjected to the instantaneous control force,the directions of the resulting balance angle of yaw and the average velocity deflection angle motion are substantially opposite to the direction of the instantaneous control force. Under the action of the fixed canards,the directions of the balance angle of yaw and the average velocity deflection angle are approximately 180° to the direction of the control force,which is a small angle difference. The motion of angle of yaw is synthesized by the instantaneous canards control force generating the opposite direction angle of yaw and the gravity generating the rightward power balance angle,and the motion law of angle of yaw will affect the centroid motion of the trajectory. The research results provide theoretical basis and reference for the control strategy and control scheme design of the high-rotation two-dimension trajectory correction projectile.

In order to improve the firing accuracy of ammunition,impulse jets and drag brakes were used to correct the trajectory. Aiming at different correct methods,the 6-degrees of freedom trajectory equations corresponding to impulse jects and drag brakes were constructed. The control method was proposed based on impact point prediction. After analyzing impulse jets and drag brakes separately,a combined correction strategy was put forward. In view of a typical rocket projectile,Monte-Carlo simulations were performed to analyze the trajectory correction precision of different correction methods. Results show that the correction effect of impulse jet on lateral deviation is obvious,and the capacity of impulse jets correcting the longitudinal deviation is inadequate. The drag brake can reduce the longitudinal deviation significantly,and it can’t eliminate the lateral deviation. The combined method is the best choice to decrease both lateral and longitudinal deviation,and the circular probable error can be improved to 28 meters. The above conclusions were validated by flight tests. The result shows that the combined trajectory correction method is effective.

To overcome the defects of long simulation period,low code reuse rate and lack ability of solving complex computation domain in the interior ballistic two-phase flow programs by the individual independent coding,a three-dimensional interior ballistic two-phase flow solver was developed in the open source finite volume software(OpenFOAM)framework. The correctness of interior ballistic solver was verified in three aspects,namely,pressure wave capture verification,global conservation verification,interior ballistic experimental results verification. The simulation analysis of ignition and flame-spreading process of the central tube dispersing system was carried out. The simulation result was compared with experiment result. The result shows that the 3D interior ballistic solver developed in this paper provides an efficient simulation tool for numerical analysis of interior ballistic problems with the ability to solve complex computational domains.

The current method of measuring terminal trajectory of torpedo is affected by sea conditions,and the construction and maintenance are difficult. Aiming at the problem,a torpedo location measurement method based on least square fitting was proposed by taking the torpedo electromagnetic field emitter as positioning signal. The position of torpedo was located by placing a magnetic sensor array on the two sides of target ship. Three kinds of motion posture of torpedo penertrating through target were simulated,such as vertical penetration,traverse penetration and oblique penetration. The coordinate points were fitted to form torpedo near-field trajectory(terminal trajectory)by using least square method. The result shows that the method can meet the positioning-accuracy requirements of torpedo under typical penetrating-target condition,and it has practical application value in torpedo research,army training and shooting-range construction.

To study the influence of gun ablative wear on interior ballistic performance,the classical interior ballistic model and gun ablative model were built based on the theory of ablative wear. The numerical simulation on gun was carried out,and the starting pressure variation law under different wear conditions agreed with the experimental results. On this basis,the influence of multi-parameter variation on artillery interior ballistic performance was numerically analyzed. The results show that barrel erosion wear will lead to the decreasement of projectile velocity and the gun pressure. With the increase of charge,the relative muzzle velocity reduction decreases as the barrel wear increases.After increasing the gunpowder power,the relative muzzle velocity reduction increases as the wear increases. Under the condition of full charge,when the number of projectile reaches about 420 rounds,the muzzle velocity drops by 7.53% compared to the new gun,reaching the barrel scrap standard,at which time the barrel is scrapped.

It is an important self-defense method for combat aircraft in future air combat to launch anti-air-to-air missile to intercept incoming missile. In order to study the interception characteristics and interception area of anti-air-to-air missile,the mathematical models of enemy aircraft,incoming air-to-air missile,self-defense aircraft and anti-air-to-air missile were derived. The air combat simulation platform was established,and the trajectory of the incoming missile attacking the self-defense aircraft and the trajectory of the anti-air-to-air missile intercepting the incoming missile were simulated in the platform,and the interception area of the anti-air-to-air missile was calculated. The simulation results show that under typical air combat conditions,there is an effective interception area for the incoming medium range air-to-air missile,and the size and shape of anti-air-to-air missile interception area is closely related to the performance of anti-air-to-air missile,launching leading angle,evasion maneuver of self-defense aircraft and launching distance of incoming missile. It can greatly improve the battlefield survival ability of the self-defense aircraft to launch anti-air-to-air missile in the interception area.

In order to develop a kind of controllable spin-stabilized projectile with stronger correction ability,a kind of spin-stabilized projectile with micro spoiler control mechanism was studied. The control principle of this kind of controlled projectile was analyzed. Aiming at its dynamic modeling problem,the mathematical model of the control force and the control torque of the spin-stabilized projectile with spoiler was established by considering the aerodynamic asymmetry. According to the six degree of freedom trajectory model,the effects of the spoiler height,projectile angle,initial velocity and start-up and control time on the stability and correction ability of the projectile were analyzed. The results show that the higher the spoiler height is,the stronger the correction ability is,but the more obvious the speed drop. The larger the oscillation amplitude and stability value of the attack angle are,the earlier the start-up and control time is. When the velocity changes from subsonic to supersonic,the correction ability first decreases and then increases.