In recent years, Wang Liwei and other M people have carried out numerical simulation and principle verification experiments on the principle of tandem warheads of annular shaped charge. Through the optimization design of the front-end ring cutter, Song Zhiyong, Wang Weili, Li Yongsheng and others have basically eliminated the damage of the annular cutter to the front stage under the premise of ensuring the damage effect of the annular jet on the front stage. influences.
In the case of explosion-proof between the two stages of the tandem warhead, which does not consider the annular shaped charge, the pre-charge explosion will have an important impact on the subsequent stage of the warhead: the air shock wave formed after the explosion of the pre-charge The effects of pressure, detonation products and fragments on the rear part of the warhead may damage or detonate the rear stage into the warhead; on the other hand, the speed of the rear stage may be reduced or the attitude changed, so that It cannot be smoothly penetrated into the hole created by the front-level warhead to explode on the target. Therefore, it is necessary to study the flameproof structure between the front and rear stages of the tandem warhead of the annular shaped charge. 4-. The numerical simulation is carried out by using ANSYS/LS~DYNA to study the flameproof characteristics of different material structures. The best material for the explosion-proof effect.
1 series warhead structure model and material model 1.1 series warhead structure model model consists of the annular cutter's charge, the shape cover, the shell, the air, the rear stage with the warhead and the flameproof body. To simplify the calculation, a 1/4 model is used, and the structure is as follows.
Numerical simulations were carried out with air, rigid polyurethane, aluminum foam, phenolic resin and steel plate + foam aluminum and steel plate + polyurethane as flameproof bodies. A gap is reserved between the flameproof material and the explosive to maintain a pressure relief effect.
The charge of the ring cutter, the hood, the air and the explosion-proof body are divided by the Euler grid unit. In the calculation, the unit uses the multi-substance ALE algorithm; the latter stage uses the La-grange network with the warhead and the ring cutter housing. Cell division. In order to ensure the accuracy and reliability of the calculation, the transmission boundary is set around the air domain to avoid the error caused by the shock wave reflection at the air boundary. For the whole model, apply the basic material parameters of Table 3 on the symmetry plane. GPa rigid polyurethane 3202 5401.5701.0701 Table 4 Basic material parameters of foam aluminum Parameter material p/E/ GPa foam aluminum 12001.20.3101.0701 Table 5 Basics of phenolic resin The material parameter parameter GruneisenEos material pG/resin 1 plus symmetry constraint, the ring cutter charge detonation method is the top ring detonation.
1.2 Material model and main parameters Explosive B explosives were described by High-Explosive~Bum model and WL equation of state; the material of the coating was copper, using Steinberg material model and Gruneisen equation of state; the shell and the rear stage were followed by the warhead. Steel, using hnson~cook material model and Grnnei-sen equation of state; air meter with Null material model and LinearPolynomial equation of state. The main parameters are shown in Table 1, Table 2M. The equation of state is simulated using the Gruneisen equation of state. The material parameters of rigid polyurethane are shown in Table 3. 1 Metal material parameters Material yield strength / MPa Young's modulus / GPa copper steel Table 2 Charge parameters Material explosion pressure / GPa B explosive foam aluminum foam model, its main material parameters See Table 4. The constitutive relationship of aluminum foam requires the engineering stress-strain curve of the input material. The stress-strain curve is shown in the fluid elastoplastic model of the furfural resin, and the equation of state is simulated by the Gruneisen equation of state. Material parameters of furfural resin 2 Numerical simulation results and analysis 2.1 Air explosion proof gives the numerical simulation results of the explosion process.
The position units with different warhead surfaces are selected, see, for example, the time history curve of the warhead.
It can be seen that the shock wave acts on the surface of the projectile around 44 mesh, and the stress at the top of the warhead reaches a maximum at around 100. The stress at the key points of A, B and C is the largest, reaching 1.26 GPa, and both are close to the top of the warhead. It shows that after the explosion of explosives, the detonation products will generate high-pressure shock waves backwards after the center gathers, which will cause certain damage to the warheads of the warheads. The warhead has signs of erosion, see. It shows that the shock wave and the detonation wave have certain influence on the rear stage warhead. 2.2 Single-layer flameproof polyurethane, aluminum foam and furfural resin are selected as flameproof materials.
The numerical simulation results of the explosion process are given.
The cells at different positions on the surface of the warhead are selected, see the time-stress history curve.
It can be seen that the shock wave propagates to the surface of the warhead at around 56 degrees. The maximum stress value of the surface of the projectile is close to 1 GPa. It shows that the shock wave after the explosion of the blasting agent is attenuated by the polyurethane and is relatively uniform on the surface of the warhead. The maximum stress is 1. 03 GPa, which appears on the top of the warhead. It shows that the shock wave is obviously attenuated after passing through polyurethane. The warhead has not deformed. See 0. It shows that the polyurethane plays a good role in protecting the rear stage with the warhead.
Similarly, the results of the foam aluminum explosion-proof are as follows: the left and right are propagated to the surface of the projectile, and the stress value is small. However, the maximum stress of 200 mesh still exceeds 1.2GPa. It indicates that aluminum foam has good resistance and attenuation effect on shock wave propagation. However, since aluminum foam hardens under high strain, it is followed by the warhead. It has a certain destructive effect. The warhead is slightly deformed. See 1. The foam aluminum has a certain protective effect on the rear stage with the warhead, but the effect is not obvious.
Similarly, the flameproof result of the furfural resin is as follows: it propagates to the surface of the warhead from left to right. The maximum stress value on the surface of the bullet head is 1.18 GPa, which appears on the top of the warhead. It shows that the shock wave after the explosive explosion has attenuated the strength after passing through the furfural resin. There is a slight deformation at the top of the warhead. See 2. Demonstrating the furfural resin to protect the rear stage from the warhead.
2 final stage warhead final deformation (phenolic resin flameproof) 2.3 double-layer flameproof selection steel plate + polyurethane and steel plate + foam aluminum as flameproof material.
3 gives the numerical simulation results of the explosion process.
It can be seen from 5 that the shock wave propagates to the surface of the warhead around 60 mesh. The maximum stress value appears on the surface of the bullet head, and the maximum stress value is 1.05 GPa. The shock wave is attenuated after passing through the steel plate + polyurethane. There is no deformation of the warhead. See 6. The steel plate + polyurethane plays a very good role in protecting the rear stage with the warhead.
6 final stage warhead final deformation (steel plate + polyurethane flameproof) The same reason to get the steel plate + foam aluminum flameproof results as follows: left and right spread to the warhead surface. The maximum stress value on the surface of the bullet head is close to 1.1 GPa, with a maximum stress of 1.14 GPa appearing at the top of the warhead. It shows that the shock wave after the explosive explosion has attenuated after passing through the steel plate + foam aluminum. There is no deformation of the warhead. See 7. It shows that the steel plate + foam aluminum plays a very good role in protecting the rear stage with the warhead. The units with different positions on the surface of the warhead are selected, see 4, and the time-stress history curve is as shown in 5. 2.4 Numerical simulation results. Through the above six sets of numerical simulation studies, the arrival time of the shock wave and the subsequent stage of the different flameproof materials are obtained. Parameters such as maximum stress on the surface of the warhead, acceleration along the warhead, and velocity curve (see Table 6).
The t in the table indicates the time when the shock wave reaches the head of the rear warhead; the maximum stress value on the head surface of the rear warhead; the maximum acceleration of the rear warhead; and the maximum speed of the rear warhead.
Table 6 simulation results data statistical comparison table explosion-proof material post-warhead deformation deformation air head depression about 2.0cm polyurethane undeformed foam aluminum head depression about 0.6cm phenolic resin head depression about 1.5cm steel plate + foam aluminum undeformed steel plate + Polyurethane is not deformed 3 Conclusions Overall, composite flameproof materials are superior to single flameproof materials.
The foam aluminum in the single flameproof material has better effect on the shock wave retardation, and the polyurethane has a more obvious effect on the shock wave attenuation. The steel plate + polyurethane flameproof effect of the multi-layer composite flameproof material is the best.
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