Simulation and ground verification method of guided projectile thermal battery needle-piercing overload activation mechanism

Abstract

The present application belongs to the technical field of guided shell overload activation thermal battery, and particularly relates to a simulation and ground verification method of a guided shell thermal battery needle-punching overload activation mechanism. The method comprises the following steps: first, establishing a needle-punching overload activation mechanism model; second, modeling and simulating the overload during the falling process of the thermal battery; and third, determining the verification indexes of the ground hammering verification test of the designed needle-punching ignition cap activation mechanism. The method can provide a basis for the design of the activation mechanism, reduce the repeated iteration and trial-and-error process, and reduce the development cycle and cost. Moreover, the ground hammering test can more accurately simulate the impact energy of real flight, provide a reliable test standard for the acceptance of the thermal battery, improve the reliability of the thermal battery activation, and greatly reduce the risk of non-activation of the thermal battery in flight.

Description

Technical Field

[0001] This invention belongs to the field of overload activation thermal battery technology for guided projectiles, specifically relating to a simulation and ground verification method for a needle-punch overload activation mechanism for a guided projectile thermal battery. Background Technology

[0002] Guided projectiles are powered after firing. Due to the high firing overload of guided projectiles (generally exceeding 2000g), the onboard thermal batteries typically use this firing overload as energy for activation. A schematic diagram of the needle-piercing percussion cap timing mechanism is attached. Figure 1 The activation mechanism is usually installed on the cylindrical end face of the thermal battery. When the projectile is launched, the entire activation mechanism accelerates forward under the action of launch overload. The firing pin compresses the spring under the action of inertial force, and the firing pin pierces the needle-punch cap at a certain speed. The needle-punch cap ignites, and the flame ignites the ignition component through the ignition hole, thereby activating the thermal battery.

[0003] The design of the activation mechanism needs to consider two main usage scenarios: reliable activation during launch and inability to activate during routine maintenance. Due to the long-term reliance on experimentation and experience in engineering practice, there is a lack of modeling, simulation, and verification indicators for the activation process. Consequently, inactivation failures frequently occur during flight tests, or accidental activations during ground maintenance. Therefore, there is an urgent need for theoretical simulation calculations of the activation process to guide the design. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by this invention is: how to provide a simulation and verification method for the design and verification of a needle-punch overload activation mechanism, and to improve the activation reliability and safety of guided projectiles.

[0006] (II) Technical Solution

[0007] To address the aforementioned technical problems, this invention provides a simulation and ground verification method for a guided projectile thermal battery needle-punch overload activation mechanism, the method comprising:

[0008] The first step is to establish a model of the acupuncture overload activation mechanism;

[0009] The second step is to model and simulate the overload during the thermal battery drop process.

[0010] The third step is to determine the verification indicators for the ground hammer impact verification test of the needle-punched fire cap activation mechanism.

[0011] The first step includes:

[0012] Step 11: Input the initial parameters of the needle stimulation mechanism; the needle stimulation mechanism consists of a spring, a needle cap, and a firing pin; the mass of the firing pin is m; the stiffness coefficient of the spring is k, the preload spring force is F0 when the initial position is x0, and the firing pin velocity is v0; the position of the firing pin when it strikes the needle cap is x1, at which time the spring force is F1 and the firing pin velocity is v1.

[0013] Step 12: Calculate the spring force F at different positions x. k =F0+kx;

[0014] Step 13: Input the launch overload 'a' and calculate the inertial force F of the firing pin. g =-ma;

[0015] Step 14: Neglecting friction, in the non-inertial frame of the system consisting of the firing pin and the spring, obtain the dynamic equation of the system according to Newton's second law:

[0016]

[0017] Step 15: Calculate the position x and velocity v of the firing pin under the action of launch overload; solve the differential equation of equation (1) by numerical method; initial condition: when x = x0, v0 = 0 m / s; final condition: x = x1; obtain the impact velocity v1 and kinetic energy at this time.

[0018] Step 16: Determine whether the velocity and kinetic energy of the firing pin during impact meet the lower energy limit Ekmin required for the firing cap to be ignited.

[0019] The second step includes:

[0020] Step 21: Determine the drop height and drop impact duration; during the drop impact, the characteristics of its overload curve depend on the drop height H and drop impact duration T of the projectile;

[0021] Step 22: Calculate the velocity v0 of the firing pin at the moment of impact; according to the free fall calculation formula,

[0022] Step 23: Calculate the velocity v1 and kinetic energy Ek1 of the firing pin when it strikes the firing pin and pierces the firing cap; In the system consisting of the firing pin and the spring, neglecting friction, the initial kinetic energy Ek0 of the firing pin when it falls is partially converted into the increase in elastic potential energy of the spring ΔEe1 when the firing pin strikes the firing pin and pierces the firing cap, and the remaining kinetic energy is the firing pin impact kinetic energy Ek1.

[0023] Ek0=Ek1+△Ee1

[0024] Step 24: Determine whether the design results meet the maximum drop height requirements based on the relationship between the firing pin impact kinetic energy Ek1 and the lower limit of the needle-punching cap excitation energy Ekmin.

[0025] In step 24, if the maximum drop height requirement is not met, the design parameters of the firing pin weight and spring stiffness coefficient are changed, and this process is iterated until the drop height requirement is met.

[0026] In step 22, g represents gravitational acceleration.

[0027] The third step includes:

[0028] Step 31: Model the impact overload signal of the ground hammer test; according to the measured curve, the impact signal is approximately a half-sine wave; the overload peak value is Gmax, and the pulse width is Ts, then the overload impact signal G of the hammer test is expressed as:

[0029]

[0030] Step 33: Based on the design parameters of the activation mechanism that meet the safety drop height index in the second step, input the initial values ​​of the overload peak value Gmax and the pulse width Ts to obtain the hammer impact signal G as the initial input of the simulation model of the activation mechanism. Simulate the model established in the first step to obtain the firing pin impact kinetic energy Ek1.

[0031] Repeat this process until the impact kinetic energy Ek1 approaches the lower limit of the energy induced by the needle-piercing cap Ekmin. At this point, the overload peak value Gmax and the pulse width Ts are the verification indicators of the ground hammer impact verification test.

[0032] (III) Beneficial Effects

[0033] Compared with existing technologies, this invention establishes a simulation and ground verification method for the needle-punch overload activation mechanism of the thermal battery in guided projectiles. This provides a basis for the design of the activation mechanism, reduces iterative trial and error processes, and lowers the development cycle and cost. Furthermore, ground hammer tests can accurately simulate the impact energy of real flight, providing a reliable test standard for thermal battery acceptance, improving the reliability of thermal battery activation, and greatly reducing the risk of thermal battery inactivation during flight. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the acupuncture overload activation mechanism.

[0035] Figures 2a to 2d These are simulation results of the needle overload activation mechanism.

[0036] Figures 3a to 3d This describes the iterative process and results of determining the peak impact overload G index in the ground hammer impact verification test. Detailed Implementation

[0037] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0038] To address the aforementioned technical problems, this invention provides a simulation and ground verification method for a guided projectile thermal battery needle-punch overload activation mechanism, the method comprising:

[0039] The first step is to establish a model of the acupuncture overload activation mechanism;

[0040] The second step is to model and simulate the overload during the thermal battery drop process.

[0041] The third step is to determine the verification indicators for the ground hammer impact verification test of the needle-punched fire cap activation mechanism.

[0042] The first step includes:

[0043] Step 11: Input the initial parameters of the needle stimulation mechanism; the needle stimulation mechanism consists of a spring, a needle cap, and a firing pin; the mass of the firing pin is m; the stiffness coefficient of the spring is k, the preload spring force is F0 when the initial position is x0, and the firing pin velocity is v0; the position of the firing pin when it strikes the needle cap is x1, at which time the spring force is F1 and the firing pin velocity is v1.

[0044] Step 12: Calculate the spring force F at different positions x. k =F0+kx;

[0045] Step 13: Input the launch overload 'a' and calculate the inertial force F of the firing pin. g =-ma;

[0046] Step 14: Neglecting friction, in the non-inertial frame of the system consisting of the firing pin and the spring, obtain the dynamic equation of the system according to Newton's second law:

[0047]

[0048] Step 15: Calculate the position x and velocity v of the firing pin under the action of launch overload; solve the differential equation of equation (1) by numerical method; initial condition: when x = x0, v0 = 0 m / s; final condition: x = x1; obtain the impact velocity v1 and kinetic energy at this time.

[0049] Step 16: Determine whether the velocity and kinetic energy of the firing pin upon impact meet the lower energy limit Ekmin required for the firing cap to be activated. (Appendix) Figures 2a to 2d The simulation results of the activation mechanism modeling are illustrated using a certain type of guided projectile as an example.

[0050] The second step includes:

[0051] Step 21: Determine the drop height and drop impact duration; during the drop impact, the characteristics of its overload curve depend on the drop height H and drop impact duration T of the projectile;

[0052] Step 22: Calculate the velocity v0 of the firing pin at the moment of impact; according to the free fall calculation formula,

[0053] Step 23: Calculate the velocity v1 and kinetic energy Ek1 of the firing pin when it strikes the firing pin and pierces the firing cap; In the system consisting of the firing pin and the spring, neglecting friction, the initial kinetic energy Ek0 of the firing pin when it falls is partially converted into the increase in elastic potential energy of the spring ΔEe1 when the firing pin strikes the firing pin and pierces the firing cap, and the remaining kinetic energy is the firing pin impact kinetic energy Ek1.

[0054] Ek0=Ek1+△Ee1

[0055] Step 24: Determine whether the design results meet the maximum drop height requirements based on the relationship between the firing pin impact kinetic energy Ek1 and the lower limit of the needle-punching cap excitation energy Ekmin.

[0056] In step 24, if the maximum drop height requirement is not met, the design parameters of the firing pin weight and spring stiffness coefficient are changed, and this process is iterated until the drop height requirement is met.

[0057] In step 22, g represents gravitational acceleration.

[0058] The third step includes:

[0059] Step 31: Model the impact overload signal of the ground hammer test; according to the measured curve, the impact signal is approximately a half-sine wave; the overload peak value is Gmax, and the pulse width is Ts, then the overload impact signal G of the hammer test is expressed as:

[0060]

[0061] Step 33: Based on the design parameters of the activation mechanism that meet the safety drop height index in the second step, input the initial values ​​of the overload peak value Gmax and the pulse width Ts to obtain the hammer impact signal G as the initial input of the simulation model of the activation mechanism. Simulate the model established in the first step to obtain the firing pin impact kinetic energy Ek1.

[0062] This process is repeated until the impact kinetic energy Ek1 approaches the lower limit of the needle-piercing cap excitation energy Ekmin. The overload peak value Gmax and pulse width Ts at this point are the verification indicators for the ground hammer impact verification test. (Appendix) Figures 3a to 3dTaking the lower limit of the firing pin excitation energy Ekmin = 5 mJ as an example, this paper illustrates how to determine the peak value of the ground hammer impact overload Gmax through several iterative simulation calculations. Initially, the peak value of the hammer impact overload Gmax is set to 1000g (with a pulse width of 1.3ms). According to the simulation results, the kinetic energy Ek1 of the firing pin impact at this time is only about 1.5 mJ, which does not meet the minimum activation energy requirement of 5 mJ. Gradually increasing Gmax (incrementing by 50g in the figure, which can be modified), after 4 iterations, when Gmax = 1200g, the kinetic energy Ek1 of the firing pin impact is 5.2 mJ, meeting the minimum activation energy requirement. Therefore, the ground hammer impact test can determine the reliable activation index as follows: when the peak value of the hammer impact overload is about 1200g and the pulse width is about 1.3ms, the thermal battery should be reliably activated.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A simulation and ground verification method for a needle-punch overload activation mechanism for a guided projectile thermal battery, characterized in that, The method includes: The first step is to establish a model of the acupuncture overload activation mechanism; The second step is to model and simulate the overload during the thermal battery drop process. The third step is to determine the verification indicators for the ground hammer impact verification test of the needle-punched fire cap activation mechanism. The first step includes: Step 11: Input the initial parameters of the needle stimulation mechanism; the needle stimulation mechanism consists of a spring, a needle cap, and a firing pin; the firing pin mass is... m The stiffness coefficient of the spring is k The initial position is x At time 0, the preload spring force is F0, and the firing pin speed is... v 0; The position where the firing pin strikes the needle cap is x 1. At this time, the spring force is F 1. The firing pin speed is v 1; Step 12: Calculate the spring at different positions x Spring force: ; Step 13: Input transmit overload a Calculate the inertial force of the firing pin. ; Step 14: Neglecting friction, in the non-inertial frame of the system consisting of the firing pin and the spring, obtain the dynamic equation of the system according to Newton's second law: （1） Step 15: Calculate the firing pin position under launch overload. x and speed v Solve the differential equation (1) using numerical methods; initial conditions are: x = x At 0 o'clock, v 0 = 0 m / s; Final value condition: x = x 1; Calculate the impact velocity at this moment. v 1 and kinetic energy; Step 16: Determine whether the velocity and kinetic energy of the firing pin during impact meet the lower energy limit Ekmin required for the firing cap to be ignited. The second step includes: Step 21: Determine the drop height and drop impact duration; during the drop impact, the characteristics of its overload curve depend on the drop height H and drop impact duration t of the projectile; Step 22: Calculate the firing pin velocity at the moment of impact. v 0; According to the free fall calculation formula, ; Step 23: Calculate the velocity of the firing pin when it strikes the firing pin and pierces the cap. v 1 and kinetic energy Ek1; In the system consisting of the firing pin and the spring, neglecting friction, the initial kinetic energy Ek0 of the firing pin when it falls is partially converted into the increase in elastic potential energy of the spring ΔEe1 when the firing pin hits the firing pin cap, and the remaining kinetic energy is the firing pin impact kinetic energy Ek1. Ek0 = Ek1 + △Ee1 Step 24: Determine whether the design results meet the maximum drop height index requirements based on the relationship between the firing pin impact kinetic energy Ek1 and the lower limit of the needle punching cap excitation energy Ekmin; In step 22, g is the acceleration due to gravity; The third step includes: Step 31: Model the impact overload signal from the ground hammer test; based on the measured curve, the impact signal is approximately a half-sine wave; the overload peak value is Gmax, and the pulse width is T. s The overload impact signal G from the hammer strike is represented as: Step 33: Based on the activation mechanism design parameters that meet the safe drop height index in Step 2, input the overload peak value Gmax and pulse width T. s The initial value is obtained, and the hammer impact signal G is used as the initial input of the simulation model of the activation mechanism. The impact kinetic energy Ek1 of the firing pin is obtained by simulation based on the model established in the first step. Repeat this process until the impact kinetic energy Ek1 approaches the lower limit of the needle-piercing cap excitation energy Ekmin. At this point, the overload peak Gmax and the pulse width T are equal. s This refers to the verification indicators for the ground hammer impact verification test.

2. The simulation and ground verification method for the needle-punch overload activation mechanism of the guided projectile thermal battery as described in claim 1, characterized in that, In step 24, if the maximum drop height requirement is not met, the design parameters of the firing pin weight and spring stiffness coefficient are changed, and this process is iterated until the drop height requirement is met.

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