The impact loading tests of shell charge with different guard plate thickness were carried out using the 25 mm smoothbore cannon, the failure modes change and charge reaction state of fragment and guard plate under impacting the charge with shell by 18.6 g standard fragment at 1 820-1 830 m/s velocity were obtained, the charge response degree were observed by high speed photography, and a protective structure that can reduce the reaction grade of the charge with shell was proposed. The results show that when the thickness of front guard plate is 10 mm, the failure mode of the front guard plate is same diameter perforation with a diameter of 28 mm, and the fragments penetrating the front guard plate form several large quality fragments. When the thickness of front guard plate increases to 16 mm, the spalling layer with a diameter of 37 mm is formed on the back of front guard plate and the fragments become dense small quality fragment groups. Compared with the charge combustion reaction caused by several large quality fragments, the dense small quality fragment groups are more easily to form multiple hot spots in the charge interior, which will lead to more intense deflagration reaction of the charge. The composite protection structure can effectively reduce the energy of fragment groups and play a good role in protecting the charge.

Aramid is widely used in the field of ballistic protection due to its light weight and high strength. In order to improve the trauma resistance of single-layer aramid fabrics, the surface modification methods of thermoplastic resin polyethylene (PE) and graphene nanoparticles (GR) are used innovatively to improve the ballistic performance of aramid fabrics. The trauma resistance and energy absorption of modified aramid fabrics with different mass ratios are studied based on the backface significance (BFS). The results show that both graphene and polyethylene modification methods can improve the blunt trauma resistance. The surface density of the modified fabric is increased slightly by polyethylene modification, but the resistance to blunt injury is significantly improved. Compared with pure aramid fabric, the bullet-proof ability and specific energy absorption value of 10% PE are increased by 18.0% and 30.8%, respectively. The increased rigidity of graphene-modified fabric increases its resistance to blunt injury at low speed, but the excessive inter-yarn friction weakens its resistance to blunt injury at high speed. 2% GR is the best ratio for graphene-modified fabric. In addition, the combined design of body armor with 2 layers of 10% PE and 13 layers of six layers of orthogonal UHMWPE unidrectional fabric is obtained through optimization and verification.

The active protection system (APS), usually installed on the turret of armored vehicles, can significantly improve the vehicles’ survivability on the battlefield by launching countermeasure munitions to actively intercept incoming threats. However, uncertainty over the launch angle of the countermeasure is increased due to angular disturbances when the off-road armored vehicle is moving over rough terrain. Therefore, accurate and comprehensive angular disturbance prediction is essential to the real-time monitoring of the countermeasure launch angle. In this paper, a deep ensemble learning (DEL)-based approach is proposed to predict the angular disturbances of the countermeasure launcher in the APS based on previous time-series information. In view of the intricate temporal attribute of angular disturbance prediction, the sampling information of historical time series measured by an inertial navigation device is adopted as the input of the developed DEL model. Then, the recursive multi-step (RMS) prediction strategy and multi-output (MO) prediction strategy are combined with the DEL model to perform the final angular disturbance prediction for the countermeasure launcher in the APS of a moving armored vehicle. The proposed DEL model is validated by using the different datasets from real experiments. The results reveal that this approach can be used to accurately predict angular disturbances, with the maximum absolute error of each DOF less than 0.1°. © 2022 China Ordnance Society

Stab-proof clothing can effectively protect life safety in terrorist attacks, medical problems, breaking the law and committing crimes and other incidents, but the mechanical creases of tab-proof clothing are easily produced in production and wearing. Based on the demand for rapid detection of crease defects of protective materials, a small sample-driven feature segmented neural network structure is proposed innovatively in the image recognition method, and the rapid and accurate detection of crease defects is realized. By introducing the attention mechanism and the depth-separable convolution module and giving the loss function and the optimizer two typical parameters, the detection accuracy and efficiency of the feature segmented neural network are improved comprehensively. A geometric information annotation algorithm is proposed and a visual detection platform is built for defect detection of protective materials, realizing the automatic and accurate location of mechanical creases and the output of geometric information. The results show that the accuracy of the model can reach 96.19%, and the annotation error of geometric information is less than 2%. The excellent visual detection function can be extended to the field of large-scale engineering automatic detection. The research work lays a foundation for constructing a protective performance prediction model of the stab-proof equipment with crease defects.

Well-developed bulletproof standards can not only correctly classify the protection grade of the bulletproof materials, but also offer efficient and practical guidance for commanders to choose different protective equipment when facing danger. Each country or an international organization establish their bulletproof standards according to their own particular circumstances, and therefore the protection levels vary from country to country. Several common bulletproof standards are summarized from four aspects: body armors, bulletproof helmets, armored vehicles and ballistic transparent materials. A side-by-side comparison of the projectile penetration energy for each protection level in different ballistic protection standards was conducted, and the bullet core and morphological structure of several of the commonly tested projectiles were compared and analyzed. Through the comparison and analysis of the commonly used bulletproof standards, the similarities and differences between domestic and foreign standards in terms of protection levels and the power of the tested projectiles were summarized. The results are expected to inspire and help researchers engaged in related industries to choose or improve their ballistic resistance standards.

To deal with the problem of blast shock wave causing traumatic brain injury, the protective performance of helmets based on blast shock waves was investigated. Combined with the pressure sensor and the head surrogate as the simulation target, the test method of protection against blast shock waves for different helmet structures and different positions in the helmet was developed. The pressure-time curves of the forehead, calvaria and back of head were obtained and the propagation principle of the blast shock wave on the surface of head with or without protection in the experiment were analyzed. The results showed that the helmets can effectively attenuated the peak overpressure of shock waves. The peak overpressure on the forehead could be attenuated from 352.57 kPa without helmet to 151.31 kPa with QGF-03 helmet and to 11.36 kPa with the full-face helmet. At the same time, the shock waves were prone to diffraction and superposition/convergence during the propagation in the head surrogate with helmet. The peak overpressure of the back of head with QGF-03 helmet and FAST helmet respectively increased by 50%-100% and 9% compared to the situation without helmet, and the duration of overpressure on head with helmet was significantly increased. The mask could significantly reduce the effect of the blast shock wave on the head and the peak overpressure of the shock wave on the forehead and face could be attenuated by 75%. The full-face helmet had the best protection effects and the peak overpressure on forehead, calvaria and back of head were respectively reduced by 90%, 87% and 80%. Moreover, the airtightness has a positive effect on protection against shock waves.

To explore the dynamic physical response of cranial brain under shock wave in warfare conditions, a physical model of protected/unprotected head surrogate impacted by shock wave from a soldier's rocket muzzle and intracranial pressure is developed. The pressure and evolution of different intracranial parts are analyzed. The intracranial pressure evolution for protected/unprotected head surrogates are compared. Under muzzle shock wave, the time-overpressure curve of unprotected intracranial pressure exhibits atypical shock wave characteristics. Unlike typical shock waves, the overpressure rises more slowly and lasts longer. The overpressure curve exhibits alternating oscillations of positive and negative pressure. The oscillation period is about 1 ms. The peak overpressure varies significantly in different intracranial parts. The counter shock side of the intracranial exhibits a significant negative pressure. The peak positive pressure on the counter shock side is nearly twice of that on the shock side, but the pressure impulses at different intracranial points are close to one another. Overpressure attenuation rates of different protected intracranial parts vary significantly. Compared with other intracranial parts, the overpressure attenuation rate of the counter shock side is highest. Moreover, the negative pressure effect on the counter shock side is weakened when covered with armor. The attenuation rate of the overpressure on the shock side is not obvious. The peak overpressure even increases in some parts with amor covered.

Boron carbide ceramics are characterized by high strength, high wear resistance, high hardness, and low density, thus being the most ideal material for ceramic armor. This study reviews the application progress of ballistic-resistant boron carbide ceramics that meet the need for high-performance and lightweight human protective equipment. Factors affecting the ballistic performance of boron carbide ballistic ceramics are analyzed, the advantages and disadvantages of different sintering processes compared, and the sintering aid system and ceramic toughening technology approaches summarized. Lastly, the challenges and development needs facing the application of boron carbide ballistic ceramics are analyzed.

To evaluate the severity of damage to the human body caused by the blunt bullet or its penetrating through the body armor when the human target wears body armor, a digital model of human body wearing an armor is developed based on real human anatomy data. Then, the process of the bullet penetrating the protected gelatin target is captured by high-speed photography. The evolution data of the instantaneous space cavity inside the gelatin target is obtained. A simplified model of the instantaneous space cavity is established. The Abbreviated Injury Scale (AIS) method is used to evaluate tissue and organ damage. Damage scores of the corresponding parts of the human body under blunt hit and penetrating hit are obtained based on MAIS and NISS damage assessment algorithms, respectively. Besides, mortality rate is predicted. Human susceptibility assessment software is developed to obtain a severity score of damage caused to the human body when a small-caliber bullet bluntly hits and penetrates the body wearing an body armor at different speeds. When a small-caliber bullet hits the human chest with a body armor at 638 m/s, it causes blunt damage; the human injury score is MAIS=3, NISS=27, and the mortality prediction result is 12.88%. When a small-caliber bullet hits at 714 m/s, it penetrates the body armor and directly invades human tissue; the human injury score is MAIS=5, NISS=75, and the mortality prediction result is 97%.

High-level explosive noise (HLEN) is a non-lethal damage accompanying explosions, which can directly damage one's auditory system. Using the mechanism analysis of the HLEN's awareness and propagation, explosive noise tests with different TNT mass are conducted to study the sound pressure (p_sp), sound pressure level (p_spl), propagation laws of free air burst (FAB), flexible explosive proof (FEP), and steel explosive proof (SEP). The HLEN protection performances of FEP and SEP are compared with that of FAB. The results show that the HLEN has typical characteristics of low frequency and high p_sp & p_spl. At 20 m to 40 m from the explosion center, the peak p_sp attenuations are about 50%, 52%, 48%, and the peak p_spl attenuations are about 5.7%, 4.7%, and 4.9% for FAB, FEP and SEP, respectively. The peak p_sp/p_spl travel time is equal, i.e., Δt_FAB=Δt_SEP=Δt_FEP=0.057 s. FEP can weaken the peak p_sp by 52% to 93.5% and reduce the peak p_spl by 4.8% to 9.1%. SEP can decrease the peak p_sp by 24.6% to 93% and reduce the peak p_spl by 1.4% to 6.9%. Human ear injuries are graded on a scale of Ⅰ to Ⅳ. With FAB, the injury is mainly grade Ⅳ and Ⅲ. With FEP, the injury is mainly grade Ⅲ and grade Ⅲ-Ⅱ. With SEP, the injury is mostly grade Ⅳ-Ⅲ and grade Ⅲ.

To address the problems of low efficiency and poor reliability in the crack detection of traditional aircraft protective grill, a crack detection device is designed based on machine vision technology. Combined with image processing technology and deep learning principles, a crack detection and calculation method for aircraft protective grill is proposed. Firstly, a detection system is designed, and the image recognition algorithm of protective grill is studied, and then, the crack images of aircraft protective grill are collected and sorted, and the crack detection data set is studied and made. Secondly, the ZF-Net, VGG-16 and ResNet-101 convolutional neural networks are used as the feature extraction networks of Faster-RCNN to detect surface cracks and defect cracks of the aircraft protective grill. The experimental results show that: the three models can achieve good detection accuracy, which are 92.79%,95.12% and 97.54% respectively; the Resnet-101 network has the best detection effect; compared with the existing machine vision detection method for protective grill cracks, the missed detection rate and false alarm rate are reduced by 22.54% and 89.28% respectively, and the detection rate is improved by 22.54%. Further research shows that the ResNet-101 network still has high detection accuracy under different lighting conditions, which shows the effectiveness of the detection device and detection algorithm. This research provides a new method for crack detection of the aircraft protective grill.

Blast-induced traumatic brain injury (BTBI) is the main form of injury for individual soldiers in the new war mode. Especially in the frequent terrorist attacks and explosion safety accidents in recent years, more and more civilians are suffering from such kind of trauma. So far, the domestic and foreign scholars have studied the brain injury caused by blast waves, but the injury mechanism, damage threshold, protection technology and injury assessment technology have not been clarified yet. Based on the extensive investigation on the latest research frontiers at home and abroad, the generation of blast waves, the types of brain injuries and its pathological characteristics, the research methods, the injury mechanism, the damage threshold and the protection methods are reviewed, focusing on analyzing the current research status and hot spots, the existing main problems and the future research direction.

With increasing ballistic threat levels, there is ever more demand on developing ceramic armor designs with improved performance. This paper presents finite element simulations that investigate the performance of silicon carbide ceramic with steel 4340 backing material and titanium alloy, graphite as buffer layers when subjected to normal and oblique impacts by a tungsten alloy long rod projectile (LRP). Depth of penetration from experimental measurements is compared with simulations to confirm the validity of constitutive, failure model parameters. Titanium alloy cover plate and graphite interface weak layer laterally spread the impact shock away from the SiC tile and reduces the amplification of the stress accumulation at the front surface of the SiC tile. The dwelling time increases before it penetrates into ceramic armor. Further, using AUTODYN® numerical simulations detailed parametric study is carried out to identify the minimum areal density armor for a given ballistic limit velocity. The equivalent protection factor for the bi-layer armor is a simple function of the cosine of the angle of impact. © 2021 The Authors

For severe damage to the lower limbs of vehicle occupant caused by the explosion shock below vehicle，a vehicle occupant lower limb protection device was designed by combining the flexible floor and the explosion-proof foot pad. The protective performance of the lower limb protection device and the influence of design parameters on the protective performance are studied based on vehicle explosive simulation，and a preferable design is determined. Static stiffness analysis of the preferable design is made to determine if it can provide sufficient support in daily use. Multi-objective optimization is performed for the structure of lower limb protection device to obtain the optimal design. The vehicle explosion simulation and test were carried out to verify this design. The results show that the occupant lower limb protection device can effectively reduce the impact to the lower limbs and significantly improve the protection ability of the lower limbs.

A sandwich structural coating with both fire resistance and thermal insulation properties is developed to improve the heat insulation/fire resistance performances of fuze and its packaging box. The use of coatings help to avoid the potential safety hazards caused by thermal stimulation. The slow and fast cook-off tests were made to analyze the thermal insulation performances of different coating structures. The results show that the fireproof coating used alone could not serve as a thermal insulation in the slow cook-off test. After applying an insulation outer coating layer, a strong protective layer could be formed under thermal stimulation. The temperature on the back side of steel plate is reduced by 32 ℃ in the slow cook-off test and 157 ℃ in fast cook-off test. The sandwich structural coating is applied to fuze shells and their packaging boxes. And it plays an important role in heat insulation/fire resistance performance. Compared with the unprotected specimen, the sandwich structural coatings could reduce the temperatures on the back side of steel plate by 21 ℃ and 33 ℃ in the slow cook-off test, and 117 ℃ and 105 ℃ in the fast cook-off test.

The mechanical properties of 30 kg/m³, 45 kg/m³ and 60 kg/m³ foamed polypropylene foams with different densities were obtained through material compression experiments, and the cranial response of a dummy under the protection of a functional gradient foam lining subjected to high velocity impact of gunshot was tested and simulated to analyze the cranial biomechanical response under the combination of homogeneous foam, positive and negative gradients, and concave and convex gradients. Based on this, a new type of bulletproof helmet capable of resisting rifle bullets was developed, and the protective effect of functionally graded foam lining in bulletproof helmet was studied. The local and overall energy absorption of the foam was analyzed. The results show that the energy absorption of the layered foam is mainly concentrated in the support layer near the head, accounting for 62.33% of the total energy absorption of the foam; the gradient structure has more significant protection effect than the homogeneous structure when the average density is the same, and the negative gradient is better than the positive gradient in protection; the convex gradient structure increases the energy absorption by at least 19.57% compared with other gradient structures while reducing the overall weight.

Whipple shield, a dual-wall system, as well as its improved structures, is widely applied to defend the hypervelocity impact of space debris (projectile). This paper reviews the studies about the mechanism and process of protection against hypervelocity impacts using Whipple shield. Ground-based experiment and numerical simulation for hypervelocity impact and protection are introduced briefly. Three steps of the Whipple shield protection are discussed in order, including the interaction between the projectile and bumper, the movement and diffusion of the debris cloud, and the interaction between the debris cloud and rear plate. Potential improvements of the protection performance focusing on these three steps are presented. Representative works in the last decade are mentioned specifically. Some prospects and suggestions for future studies are put forward. © 2020 The Authors

The porous foam aluminum alloy plate not only overcomes the shortcomings of the traditional protective structure such as heavy weight and inconvenient transportation, but also has the advantages of fatigue resistance and high specific strength. The lightweight and efficient anti-explosion protection materials are of great significance. The finite element analysis software LS-DYNA is used to numerically simulate the failure mode and protection performance of the sandwich composite plate under the combined action of shock wave and fragment, and analyze the effect of the foam aluminum sandwich structure on the deformation of the backboard under different arrangements. The results show that, at a detonation distance of 40 cm, the fragments will act on the target plate before the shock wave, and the fragment load strength is far greater than the shock wave load strength. When the arrangement of foam aluminum and fiber is “1 mm-thick aluminum alloy panel +10 mm-thick foam aluminum +10 mm-thick foam aluminum +10 mm-thick fiber +1 mm-thick aluminum alloy backplane”, the deformation displacement of the backboard is the smallest, and the total internal energy of the structure is the highest, which are 13.9 mm and 52.7 kJ, respectively. The overall deformation degree of the structure can be more effectively reduced and the energy generated by the panel deformation is absorbed under the working condition.

The explosive reaction degree and protection from explosions are concerns in the military field. In this work, the reaction degree of the composition B explosive was investigated experimentally. Multi-layered compound structures were used as barriers to weaken the blast loads. A comprehensive experiment using a high-speed camera and image processing techniques, side witness plates, and bottom witness plates was presented. Using the experimental fragment velocities, fragment piercing patterns, and damage characteristics, the reaction degree of the explosive impeded by different multi-layered compound structures could be precisely differentiated. Reaction parameters of the explosive obstructed by compound structures were obtained by theoretical analysis and numerical simulations. Unlike the common method in which the explosive reaction degree is only distinguished based on the initial pressure amplitude transmitted into the explosive, a following shock wave reflected from the side steel casing was also considered. Different detonation growth paths in the explosive formed. Therefore, all these shock wave propagation characteristics must be considered to analyze the explosive response impeded by compound structures. © 2020 The Authors

The article presents problems related to mechanical protection of vehicles with different add-on armours against chemical, biological and radiological contamination. This applies to vehicles with additional passive, reactive and hybrid protection in the form of cassettes against piercing with anti-tank projectiles, piercing with their kinetic energy of impact, and as a result of chemical energy of shaped charges as well as explosively formed projectiles. It has been shown how increased ballistic protection of these vehicles at the same time reduces their decontaminability in various places of the vehicle due to the increased additional surface of the vehicle with cassettes. Prevention of contamination of these cassettes has been presented as a way of reducing hard to reach surface for decontamination and a method of insulating construction elements (stands), fixing these cassettes to the vehicle, from the environment to prevent contact with contaminated liquids and dusts. The selection of appropriate materials is shown, which may affect the improvement of the decontamination efficiency of the vehicle with such cassettes. This applies to the use of materials with low absorption of chemical warfare agents, which prevent the accumulation of large amounts of these agents on contaminated surfaces and improve the effectiveness of decontamination. It also shows how to ensure better access of the disinfectant to as much of the vehicle surface as possible, covered with cassettes that have been contaminated. It shows how a vehicle, in particular with such cassettes, can provide protection against radar detection when Radar Absorbent Material is used on vehicle cassettes. © 2020 The Authors

In order to investigate the penetrating mechanism of a rifle bullet against the gelatin target with soft/hard composite armor in detail, a numerical model is established by using finite element analysis software ANSYS/LS-DYNA. The blunt impact phenomena during penetrating process and the transient response of gelatin and simulated using the proposed model, and are validated by experiment. The investigation results show that the kinetic energy of rifle bullet is mostly dissipated during the process of penetrating a ceramic plate. The temporary cavity in the gelatin presents in the basic form of ellipsoid, and the maximum depth and expansion velocity of cavity are 25.6 mm and 35.7 m/s, respectively. The pressure wave propagates in gelatin in the form of spherical wave with the largest peak pressure at the impact location, and the pressure amplitude decreases with the increase in travelling distance. The velocity of riflebullet decreases firstly while the absolute value of acceleration increases, and then they both gradually attenuate to 0. The failure of ceramic plate is mainly caused by the interaction of the compressive and tensile stresses. The numerical results are coincided with the experimental results. Key

In order to effectively combat the laser guided weapons and improve the survivability of vehicle-mounted weapon systems on the battlefield, we proposed a laser induced bias interference countermeasures technology for vehicle-mounted active defense systems. According to the incoming threat information and characteristics of semi-active guided weapon systems, we discussed the feasibility of laser induced interference technique.Moreover we recorded the trajectory of the tracking system from tracking and identifying the target to starting the interference system by experimental device with synchronous forward interference mode. It is verified that the system can implement interference antagonism within 7 s and reach active protection ability.

The liquid cabin with multi-layer protective structure plays an important role in defending the loadings of combined high-speed fragments and blast wave, which are usually due to the close-in explosion of a cast charge, and cause severe damage to the structure of liquid cabin. A new composite structure of liquid cabin is designed based on the dynamic response characteristics and failure mode of liquid cabin under the synergistic effect of high-speed fragments and blast wave. In order to investigate the anti-blast performance of composite liquid cabin, the traditional liquid cabin and newly designed composite liquid cabin are experimentally test under the blast load of cased charge. The fragment velocity, bulkhead deformation, perforation size, strain and shock wave pressure are obtained. The experimental data are analyzed and compared.It is found that, in the composite liquid cabin, the maximum deformations of front and rear bulkheads are decreased by 22.78% and 8.47%, respectively, the plastic strain is decreased by 30%, and the shock wave peak is decreased by 18.62%. Key

The fast rise time electromagnetic pulse (FREMP) is an important cause of damage to electronic equipment, and the PIN diode can effectively suppress electromagnetic pulse. In order to investigate the transient response of PIN diodes to FREMP, a time-domain equivalent circuit model based on PIN diodes is adopted. And the transient voltage characteristic of PIN diode circuit under the effect of FREMP is analyzed. Considering the parasitic components of PIN diodes and the bonding wire inductance, the whole physical structure of FREMP protection module is set up based on Butterworth low pass filter model. A FREMP protection module is realized. The measured insertion loss of protection module is lower than 0.38 dB in 1-250 MHz.At large signal condition with input square wave pulse of 4 000 V, the response time is less than 2 ns and the output level is lower than 30 V, which meets the protection requirement of FREMP. Key

This paper presents a view of some of the challenges that are presented in investigating protection methodologies against explosive blast effects. In particular, the paper is concerned with experimental efforts that can aid in the understanding of complex blast effects in typical real world scenarios. Current progress in the implementation of blast mitigation methodologies in the landward defence environment is reviewed. © 2018

In order to ensure the safety of plant protection unmanned aerial vehicles (UAVs), it was required to have the ability of the automatic obstacle avoidance. So a new obstacle detection method based on structured light vision was proposed. In order to improve the real-time performance of obstacle detection, based on the analysis of the latest general processor unit (GPU), the obstacle detection system of plant protection UAVs based on embedded platform was studied mainly. By mapping the obstacle image processing algorithm to GPU hardware resources to complete the parallel computation, the efficiency of the algorithm was greatly improved. Experiments show that the obstacle detection system based on embedded CPU-GPU achieves a speedup rate of about 46.15 by comparing the processing algorithms of CPU and CPU-GPU on the premise of ensuring the complete outline of the obstacle, and time-consuming of the acquisition and processing is about 48.985 ms. The system has the advantages of obvious effect of processing and good real-time performance, which lays the foundation for real-time obstacle detection and further obstacle avoidance of plant protection UAVs.

The dynamic responses of projectile-borne electronic devices which are protected by encapsulating materialunder impact loading are studied through numerical simulation. A LS-DYNA user defined material subroutine is established according to the ZWT nonlinear viscoelastic model which is used for simulating the dynamic response of the encapsulating material in the projectile. The simulations of projectile penetration were performed by adjusting the controllable parameters of ZWT model, such as nonlinear elasticity modulus, low strain rate Maxwell elastic constant, high strain rate Maxwell elastic constant, high strain rate Maxwell relaxation time and material density. Thus the dynamic responses of projectile-borne electronic devices could be obtained from the numerical results. The research results show that the shock absorption and protection effects of the encapsulating materials are better when the values of nonlinear elasticity modulus, low strain rate Maxwell elastic constant, high strain rate Maxwell relaxation time and material density are decreased. Key

The core task of tank overall design is to get the best overall performance, minimum size and minimum weight without increasing the technical difficulty of parts. Relationship among the three main performances and the general dimensions of main battle tank (MBT) is analyzed by decomposing the specifications of firepower, mobility and protection. An optimization model is established for MBT's firepower, mobility and protection performance based on physical dimension. Restraining the height of tank is the key to coordinate the firepower, mobility and protection performance of tank. Approaches to restrain the height, width and length of tank are proposed.Key

The destruction forms of soft body armor penetrated by pistol cartridge are analyzed according to the penetration characteristics of pistol cartridge. A motion model of pistol cartridge penetrating into the gelatin target with soft body armor is established by introducing the fiber constitutive model and gelatin elastic model based on the material constitutive model of ultrahigh molecular weight polyethylene. The motion model is calculated by taking two pistol cartridges with the diameters of 9 mm and 5.8 mm as killer elements. At the same time, the numerical calculation and experimental verification are carried out, respectively. The calculated results are compared with the corresponding experimental results. The compa-rativeresult shows that the motion model can describe the motion of pistol cartridge penetrating into the gelatin target with soft body armor accurately.Key

In order to explore the protecting effect of venting structure with light and fragile material on gas explosion in building,the dynamic characteristics of venting structure under gas deflagration condition are analyzed according to the characteristics of internal gas deflagration overpressure and the protective theory of venting structure with light and fragile material. The vented explosion tests are performed by the gas explosion loading experimental equipment. The principles of using the venting structure with light and fragile material are proposed according to the current national design code of venting deflagration, which can be used in engineering protection of indoor gas explosion. The experimental verification methods of venting performance are also presented. The research results show that,for a venting structure with calcium silicate board, the opening dynamic pressure decreases with the increase in the duration time of gas deflagration pressure. Such venting structure should be used in the case of internal gas deflagration pressure with long duration time, and the opening dynamic pressure is regarded as its venting index and the venting performance test should be made. Key

In military applications, pulse forming network (PFN) needs to generate a flat-top current waveform by sequentially firing pulse forming units (PFUs)for the uniform acceleration of armature. However, when PFN works under this condition, a fly-wheel diode in PFN withstands a high reverse recovery voltage which may cause the failure of the fly-wheel diode. An approach in which the damage of semiconductor device can be eliminated by preventing from the reverse voltage is proposed through the theoretical analysis of reverse recovery process of diode. The mathematical expression of the proposed approach is derived from the equations of PFN circuit. This expression is used to calculate the parameters of a 600 kJ pulse power supply (PPS) constituted of 8 individual 75 kJ PFN modules. The PPS successfully generates an approximate flat-top current waveform without device damage. The test results show that the reverse recovery voltage can be eliminated by selecting proper circuit parameter. Key

The metastable energetic materials were prepared for the space debris shield. Hypervelocity impact tests of PTFE/Al energetic material shield under the conditions of different areal densities, projectile diameters, and impact velocities were conducted by using two-stage light gas gun, and the high speed photographs and the signals from optical pyrometer during impacting were obtained. The analysis results show that the shock initiation of PTFE/Al energetic material shield occurs in the instant of hypervelocity impact, and the perforation process can be divided into three stages: shock detonation, fracture and deflagration, and zero reaction and crushing. A dimensionless empirical expression for perforation diameter of PTFE/Al shield is established based on the experimental results of hypervelocity impact. The effect of ambient temperature on the perforation characteristics of energetic material shield is investigated. Key

To solve the issues of armored vehicle's protective area reduction, relatively complex installation process and so on, which are led by those conventional installation ways like bolting or rack supporting, a novel protective armor installation technology, called bonding technology, is presented. The kind and preparation technology of bonding agent are determined by the characteristics of installing structures. An optimal glued structure design for protective armor is proposed by studying the effects of different glued joint thickness and bonding areas on bonding strength. The bonding technology for installation is proved to be feasible and reliable through the simulated car broadband vibration test and the environmental extreme temperatures suitability assessment test. For the tests mentioned above, the bonding thickness is 2~3 mm; multi-point small area is glued ; the bearing capability is more than 3 MPa shear stress per square centimeter of bonding area; the bonding strength at extreme temperature from -50 ℃ to 70 ℃ is not less than 70% of corresponding strength at normal temperature. The results show that the two-component polyurethane adhesive is able to satisfy the dynamic broadband vibration requirement. Key

Bottom protection，which is of great significance for improving the survivability of military vehicles and providing effective protection for crew，has become one of the research hotspots of the military vehicles. The research on bottom protection technique of military vehicles, the analysis of protection capability and optimization of structure based on numerical simulation, the evaluation of bottom protection capability, the bottom protection strategies and their applications, the technical measures and protection capability of typical vehicles are reviewed. The technical measures which include V-shape bottom hull, tabulate bottom floor made of new type material, interior structure of vehicle and crew restraintsystems are expatiated. The application and researchstatus of numerical simulation technology which is used to analyze the protection capability of military vehicle and optimize the bottom structure of vehicle are discussed. The research status of the effects of explosion shock on vehicle and its crew and the test evaluation of the bottom protection abilities of vehicle are analyzed. Simple local protection, locally added protection kits, special protection body with protection kits, and integrated protection solution are summed up. The bottom protection measures and capability of typical vehicles are analyzed. In addition，the future research direction andpriorities of bottom protection , and how to develop the protection capability of military vehicles are suggested.

The electromagnetic driving technology can be used to simulate the high overload environment in the process of fuze launching, but it may stimulate magnetic field, which has negative effects on the test fuze. Thus, it is necessary to take the electromagnetic shielding measures for test fuze. The structure and working principle of the overload experiment device for fuze based on electromagnetic driving is introduced, and then the electromagnetic shielding cover for test fuze is designed. A simulation model is established for fuze overload experiment device based on electromagnetic driving, and then the intensity of magnetic field in fuze is analyzed at three occasions: without shielding cover, shielding cover made by aluminum, shielding cover made by aluminum and steel. The results show that the maximum magnetic field in fuze is 1.54 T, 0.17 T and 4.2×10^-5 T at the occasions mentioned above, respectively, which means that the shielding cover made by aluminum and steel has better shielding performance.

During this research, experimental rolled homogeneous armour steel was cast, annealed and laser cut to form an appliqué plate. This Martensitic–Bainitic microstructure steel grade was used to test a novel means of engineering lightweight armour. It was determined that a laser cutting speed of 1200 mm/min produced optimum hole formations with limited distortion. The array of holes acts as a double-edged solution, in that they provide weight saving of 45%, providing a protective advantage and increasing the surface area. Data collected were used to generate laser cut-edge hole projections in order to identify the optimum cutting speed, edge condition, cost and deformation performance. These parameters resulted in the generation of a surface, with less stress raising features. This can result in a distribution of stress across the wider surface. Provided that appropriate process parameters are used to generate laser cut edges, then the hardness properties of the surface can be controlled. This is due to compressive residual stresses produced in the near edge region as a result of metallurgical transformations. This way the traverse cutting speed parameter can be adjusted to alter critical surface characteristics and microstructural properties in close proximity to the cut-edge. A relationship was identified between the width of the laser HAZ and the hardness of the cut edge. It is the thickness of the HAZ that is affected by the laser process parameters which can be manipulated with adjusting the traverse cutting speed. © 2016 The Author

It is inevitable to evaluate the aerodynamic heat and the ablation of thermal protection material for designing a hypersonic aircraft. A coupling method is presented for the calculation of aerodynamic heat, material ablation and transient temperature distribution. The method and program are validated by experimental data. The results indicate that the method has higher precision and efficiency. For a given trajectory, the aerodynamic heat, ablation performance of thermal protection layer and temperature filed are predicted by the coupling method. The proposed method can be used to calculate the ablation and temperature distribution in given operation conditions in design phase which is referable for the design of multi-layer thermal protection material for hypersonic aircrafts.

The multi-objective optimization of vehicle bottom structure under landmine explosion is a mass computation, strong-nonlinearity and high dimension multi-objective optimization problem. The protective vehicle structure response is simulated based on combination of LAE and FSI methods. The thickness and geometry parameters of vehicle bottom structure are screened with sensitivity analysis. A response surface is built by employing the experimental design and regression analysis. Eventually, the Pareto optimality, normal boundary intersection and multi-objective optimization genetic algorithms are applied to get the Pareto optimal front and an ideal solution which could give a comprehensive consideration of the contradiction between lightweight and protection capability.

A hierarchy conceptual model of the armor protection of engineer equipment was constructed and the method of analyzing and calculating its cost and effectiveness was proposed. Taking wheeled engineer equipment as an example, the cost-effectiveness analysis model was solved by the dynamic programming method. The sensitivity analysis of the calculated results indicates that it is necessary to enhance the multilayer protection construction to improve the survival probability of battlefield multi?layer protection of engineer equipment.

The multi-waveband infrared antireflection and protection film, on the ZnS dome which di- amter is 150 mm, the thicKness is 6 mm and the radius of curvature is larger, was plated by the method oi electronic beam vaccum deposition and ion-beam assisted deposition. The film average trans?missivity is above 90% in 3?5 μm and 92% in 8?10 μm, ana it can pass the mal-condition tests.