Experimental Study on the Thermodynamic Damage Power of Ammunition Deflagration in a Closed Explosive Device

The high temperature and high pressure gas produced by propellant deburning has strong thermal effect,which will produce strong thermal damage effect on the target. In this study, an improved closed explosive device was used to simulate the thermal shock loading of 5/7 single base propellant with a charge mass of 17.4 g, and the change law of heat flow density of propellant in the process of deflagration in a closed environment was tested. The experimental results show that the temperature rises rapidly during the deflagration of the 5/7 single-base propellant, and the maximum heat flow density can reach 17.68 MW/ m2 . The curves obtained from the three tests have good consistency in the change trend, which proves the engineering practicability of the improved closed explosive device in the study

Introduction to Drone Detection Radar with Emphasis on Automatic Target Recognition (ATR) technology

This paper discusses the challenges of detecting and categorizing small drones with radar automatic target recognition (ATR) technology. The authors suggest integrating ATR capabilities into drone detection radar systems to improve performance and manage emerging threats. The study focuses primarily on drones in Group 1 and 2. The paper highlights the need to consider kinetic features and signal signatures, such as micro-Doppler, in ATR techniques to efficiently recognize small drones. The authors also present a comprehensive drone detection radar system design that balances detection and tracking requirements, incorporating parameter adjustment based on scattering region theory. They offer an example of a performance improvement achieved using feedback and situational awareness mechanisms with the integrated ATR capabilities. Furthermore, the paper examines challenges related to one-way attack drones and explores the potential of cognitive radar as a solution. The integration of ATR capabilities transforms a 3D radar system into a 4D radar system, resulting in improved drone detection performance. These advancements are useful in military, civilian, and commercial applications, and ongoing research and development efforts are essential to keep radar systems effective and ready to detect, track, and respond to emerging threats.Comment: 17 pages, 14 figures, submitted to a journal and being under revie

An introduction to radar Automatic Target Recognition (ATR) technology in ground-based radar systems

This paper presents a brief examination of Automatic Target Recognition (ATR) technology within ground-based radar systems. It offers a lucid comprehension of the ATR concept, delves into its historical milestones, and categorizes ATR methods according to different scattering regions. By incorporating ATR solutions into radar systems, this study demonstrates the expansion of radar detection ranges and the enhancement of tracking capabilities, leading to superior situational awareness. Drawing insights from the Russo-Ukrainian War, the paper highlights three pressing radar applications that urgently necessitate ATR technology: detecting stealth aircraft, countering small drones, and implementing anti-jamming measures. Anticipating the next wave of radar ATR research, the study predicts a surge in cognitive radar and machine learning (ML)-driven algorithms. These emerging methodologies aspire to confront challenges associated with system adaptation, real-time recognition, and environmental adaptability. Ultimately, ATR stands poised to revolutionize conventional radar systems, ushering in an era of 4D sensing capabilities

Analysis on propagation law of shallow underground chemical explosion seismic waves

Introduction: Seismic waves generated by shallow underground explosions propagate differently from those generated by surface explosions. Thus, an accurate understanding of the propagation laws of seismic waves generated by explosions at various burial depths and TNT equivalent amounts is significant in assessing the destructive power of munitions and establishing guidelines for their application.Methods: In this study, we conducted several ground vibration velocity tests of shallow underground chemical explosion seismic waves for various TNT equivalent amounts and burial depths in a shooting range and analyzed the propagation of the seismic waves. Using the explosion similarity theory and dimensional analysis, we derived an equation for the estimation of the particle vibration velocity of shallow underground chemical explosion seismic waves. This equation calculation results have a very high degree of agreement with the measured data, measured data verify that the accuracy of the calculation model is better than 90.2%.Results and discussion: This equation calculation results have a very high degree of agreement with the measured data, measured data verify that the accuracy of the calculation model is better than 90.2%, which greatly improves the calculation accuracy of the shallow underground chemical explosion seismic wave particle vibration velocity, and thus provide effective theoretical support for analyzing explosion seismic waves in engineering tests

Study on the ground impact vibration intensity model of high energy warhead explosion

Introduction: In the warhead explosion process, the ground impact vibration intensity will directly affect the target buildings and instruments safety, and it is also of great significance to accurately evaluate the ammunition explosion damage power.Methods: In this study, the finite element numerical simulation method was used to analyze the explosion shock wave pressure and ground shock vibration velocity of TNT explosive with a mass of 100 kg∼1000 kg, and the ground transmission medium of sandy soil, C35 and C140 concrete, and the shock wave pressure and ground shock vibration velocity propagation and distribution law was clarified. Based on the explosion similarity law and dimensional analysis method, a ground impact vibration velocity theoretical calculation model with clear physical significance is established by introducing the property ground propagation medium parameters, taking into account the factors affecting the ground impact vibration velocity.Results: The model calculation accuracy is verified by the measured data. The verification results show that the model calculation accuracy is higher than 91.8%, which improves the calculation accuracy of the explosion site ground impact vibration velocity.Discussion: This research provides more accurate and scientific theory and data support for the ammunition explosion damage power evaluation, and provides a reference for the shock and vibration resistance performance design of instruments, equipment and buildings. It has strong engineering application value

Influence of sensor installation tilt angle on explosion shock wave pressure test

The surface reflection pressure sensor installation flatness will directly lead to the change of the explosion shock wave pressure propagation and distribution law, affecting the test results accuracy, and the test data cannot accurately evaluate the ammunition explosion damage power. In this study, the numerical simulation model of the explosion shock wave pressure propagation and distribution law was established by using the explosive mechanics simulation software, and the pressure distribution law was studied when the sensors installation angles were 0°, 4°, 8°, 12°, −4°, −8°, and −12° respectively. Combined with analysis of the pressure peak value and the pressure evolution nephogram at different measuring points, it is clarified that the positive tilt angle of the sensor installation has an enhancing effect on the pressure peak, while the negative tilt angle has a attenuation effect on the pressure peak. Based on the calculation function formula of the surface reflected pressure peak value in the national defense engineering design code, the surface reflected pressure peak value correction function formula is established by introducing the sensor installation angle correction effect. This study results provide a theoretical basis for the design of ammunition explosion shock wave pressure engineering test scheme and the test data validity verification

Measurement and Analysis of Shock Wave Pressure in Moving Charge and Stationary Charge Explosions

Shock wave pressure is one of the most important parameters in an explosion. However, there have been few experimental and analytical investigations of moving charge explosions. In this article, we present an experimental method to measure the shock wave pressure from a moving charge explosion. Tests of stationary charges and moving charges with speeds of 580 m/s, 703 m/s and 717 m/s were carried out. The shock wave pressure curves and parameters at different measurement points were obtained and analyzed. The theoretical calculation of the shock wave overpressure was studied and compared with the experimental result. The differences between the stationary charge and moving charge explosions were investigated. The results showed that the shock wave pressure distribution of a moving charge had strong directionality. The shock wave pressure parameters (including overpressure, arrival time, duration and impulse) were influenced by the charge’s moving velocity, direction angle and distance from the blast point. The shock wave overpressure value was greater than that of a stationary charge explosion at angles between 0° and 90°. The correlation model based on the velocity vector superposition method could describe the relationship of overpressure between the stationary charge and moving charge explosions

Study on evaluation method for driving fragment ability of explosives

Abstract The present study proposes an evaluation method for the driving fragment ability of explosives, which aims to provide theoretical and technical support for the selection of explosives used in warheads. The evaluation method is proposed in the light of the dimensional method and the similarity principle, and it uses TNT equivalent as the evaluation indicator. To acquire the evaluation indicator, a test system for driving fragment ability of explosives is constructed, which includes a dynamite gun type driven device, a spherical fragment, and a multi-zone fragment velocity measurement system. TNT and thermobaric explosive were used to carry out the verification experiments of the evaluation method. On the basis of the evaluation method, the basic evaluation model for the driving fragment ability of explosives was established by the TNT mass and the corresponding fragment maximum velocity. Using the basic evaluation model, the TNT equivalent of the thermobaric explosive in driving fragment ability was calculated to be 1.29, which was 3.2% different from the ratio (1.25) of both explosives’ Gurney-specific energy. The relative error of 3.2% falls within the allowable range of engineering error, confirming the feasibility of the proposed evaluation method. The result shows that the proposed evaluation method is effective and accurate in evaluating the driving fragment ability of explosives

Study on Correlation Characteristics of Static and Dynamic Explosion Temperature Fields

The warheads such as missiles and artillery shells have a certain speed of motion during the explosion. Therefore, it is more practical to study the explosion damage of ammunition under motion. The different speeds of the projectiles have a certain influence on the temperature field generated by the explosion. In this paper, AUTODYN is used to simulate the process of projectile dynamic explosion. In the experiment, the TNT spherical bare charges with the TNT equivalent of 9.53kg and the projectile attack speed of 0,421,675,1020m/s were simulated in the infinite air domain. The temperature field temperature peaks and temperature decay laws at different charge rates and the multi-function regression fitting method were used to quantitatively study the functional relationship between the temperature and peak temperature correlation calculations of static and dynamic explosion temperature fields. The results show that the temperature distribution of the dynamic explosion temperature field is affected by the velocity of the charge, and the temperature distribution of the temperature field is different with the change of the charge velocity. Through the analysis and fitting of the simulation data, the temperature calculation formula of the static and dynamic explosion temperature field is obtained, which can better establish the relationship between the temperature peak of the static and dynamic explosion temperature field and various influencing factors, and use this function. Relational calculations can yield better results and meet the accuracy requirements of actual tests