钨锆合金破片毁伤过程研究

采用12.7mm弹道枪发射破片进行模拟穿靶试验,对钨锆合金、93钨合金和易碎钨合金3种材料破片在毁伤油箱过程中的瞬态压力、压力恢复时间和油箱内烃气浓度进行研究。研究结果表明,钨锆合金破片优于93钨合金和易碎钨合金破片,钨锆合金破片使油箱爆燃的主要影响原因是其碎片分散角大和多火点引燃,因此钨锆合金具有更高的引燃油箱能力。将其应用于多功能战斗部中可以使武器具有更高的综合毁伤威力。     

破片对模拟聚能战斗部装药冲击起爆研究

研究了破片对模拟聚能战斗部装药的冲击起爆问题.针对破片对聚能战斗部作用的工程问题进行等效模型简化,设计了模拟战斗部靶标及破片撞击试验方案,进行了1000～1500m/s速度范围内的冲击起爆试验,获得了装药被引发反应特性.与数值模拟进行对比,给出了破片对模拟聚能战斗部装药撞击起爆速度阈值.研究结果对反聚能装药战斗部破片杀伤元素设计具有指导意义.     

偏心起爆定向战斗部威力研究

为研究偏心起爆定向战斗部毁伤威力,推导了偏心起爆点对侧延长线附近有限角度内应用的偏心起爆破片初速公式,并设计钨柱和钨球两种预制破片偏心起爆定向战斗部进行了试验验证。结果表明,所推导公式可用于偏心起爆定向战斗部计算。设计的偏心起爆战斗部的速度增益,钨柱破片为10.9%,钨球破片为19.8%。钨球破片初速、破片球面分布密度、毁伤概率均高于钨柱破片。     

钨合金穿甲弹对超音速导弹战斗部冲击起爆研究

为研究高速钨合金穿甲弹对超音速导弹战斗部的冲击起爆特性,应用Lee-Tarver点火增长模型进行了数值模拟,获得了钨合金穿甲弹冲击起爆超音速导弹战斗部的机制以及弹目交汇角对冲击起爆的影响规律。结果表明:钨合金穿甲弹对超音速导弹战斗部的冲击起爆,发生在穿甲弹绝热剪切装药的阶段;偏轴距离相同,冲击起爆超音速导弹战斗部的能力,先与入射角大小成正比,后成反比;入射角相同,偏轴距离越小,冲击起爆超音速导弹战斗部的能力越强。     

双钨球破片同时冲击柱壳装药起爆响应规律

针对双钨球破片冲击起爆柱壳装药问题,采用LS-DYNA数值模拟软件和Lee-Tarver点火与增长模型,建立双钨球破片冲击起爆柱壳装药数值计算模型,分析炸药不同点火与增长模型参数对破片冲击起爆装药计算结果的影响.研究双破片同时撞击产生的冲击波相互作用过程及其对破片临界起爆速度的影响机制,获得不同破片间距下的临界起爆速度.结果表明:同种炸药、不同Lee-Tarver模型参数计算得到的临界破片速度相差较大,模型参数的选取严重影响计算结果的准确性;与单破片相比,双破片同时冲击装药产生的冲击波叠加效应使破片临界起爆速度更低,装药更容易被起爆,这是叠加冲击波压力峰值及其持续时间共同作用的结果.     

钨合金圆筒爆破试验破片分布的统计分析

采用圆筒爆破试验方法研究了易碎型钨合金的破片分布特征,并与93W合金的结果进行了对比.对破片的数量和质量分布特征进行了统计分析,发现易碎型钨合金的破片率明显高于93W合金,而且破片的均匀性也明显好于93W合金,但易碎钨合金的破片回收率低于93W合金,而且受装药量的影响较大.     

破片对不同壳体炸药冲击起爆研究

为研究不同壳体材料对破片撞击带壳Comp B装药的影响,利用AUTODYN-2D软件建立破片撞击带壳炸药模型,对破片撞击、起爆不同壳体炸药的过程进行数值仿真。采用"升—降"法确定破片撞击带壳炸药的临界起爆速度,并定量分析了临界起爆速度随壳体密度、强度的变化规律,仿真计算结果能够较好地符合Jacobs-Roslund经验准则。壳体材料采用钨合金时,临界起爆速度较高强工具钢提高了22.5%,较中强钢提高了24.4%,较铝提高了38.8%。仿真结果表明破片撞击起爆带有高密度、高强度材料壳体的炸药时,临界速度更高。为传统弹药的改进及不敏感战斗部的设计提供了壳体材料选择的依据。     

结构参数对复合装药战斗部破片特性的影响

为了研究结构参数对复合装药战斗部破片特性的影响,采用AUTODYN-3D有限元计算软件,比较分析了复合装药战斗部在中心单点和内外同时两种起爆方式下爆轰波传播与壳体破碎过程,获得了壳体壁厚与中心装药直径对复合装药战斗部破片平均质量、破片速度等参数的影响规律。计算结果表明,随着壳体壁厚的增加或者中心装药直径的减小,单点起爆下破片平均质量相对于内外同时起爆下提高的倍数越来越大,战斗部在不同起爆方式下威力输出差异越来越明显;静爆试验结果表明,内外同时起爆下的破片平均速度、冲击波超压和验证靶冲孔数较单点起爆下分别提高了27.1%、31.4%和39.3%,试验结果与仿真计算结果吻合较好。     

活性破片引燃航空煤油实验研究

进行弹道炮发射实验,研究活性破片和钨合金破片作用模拟油箱和引燃航空煤油问题。实验结果表明：在1 080 m/s着速下,活性破片击穿10 mm厚LY12铝靶后能可靠引燃航空煤油,而同质量钨合金破片以1 643 m/s的速度命中油箱,只造成油箱穿孔及漏油,未能引燃燃油;常温状态下,活性破片较钨合金破片具有更强的引燃航空煤油能力,活性破片的内爆作用和化学能释放是造成油箱结构严重破坏和燃油燃烧的主要原因。进行弹道炮发射实验,研究活性破片和钨合金破片作用模拟油箱和引燃航空煤油问题。实验结果表明：在1 080 m/s着速下,活性破片击穿10 mm厚LY12铝靶后能可靠引燃航空煤油,而同质量钨合金破片以1 643 m/s的速度命中油箱,只造成油箱穿孔及漏油,未能引燃燃油;常温状态下,活性破片较钨合金破片具有更强的引燃航空煤油能力,活性破片的内爆作用和化学能释放是造成油箱结构严重破坏和燃油燃烧的主要原因。     

预制破片对战斗部冲击起爆数值模拟

分析了高速条件下预制破片冲击起爆巡航导弹战斗部的作用杌理,采用 Lee-TaEver 点火增长模型和AUTO-DYN程序对高速预制破片冲击起爆战斗部进行了数值模拟,着重分析了破片材料、直径、形状和被起爆战斗部装药及壳体对冲击起爆的影响.结果表明,对于相同质量的破片,大密度和不规则的破片更容易冲击起爆战斗部;通过采用重金属材料,增大破片直径,采用柱形或其它不规则破片,可以提高破片速度来提高破片冲击起爆战斗部的能力.     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Design and Analysis of Test Schemes of Static Postponing Time on Shrapnels Used to Riot Control

The test scheme of static postponing time given in our actual national military test standard on shrapnels used to control riot is a nine-point test scheme on the combined action of three kinds of temperatures and three kinds of pressures,the consumed ammunitions are more excessive. Statistic analysis and tentative checkout about a lot of test data are done,feasibility gists are put forward for optimizing of the test design scheme. The optimizing design and data analysis of test scheme of the item are done by managing uniformity design theory, two scientific and reasonable six-point test schemes are confirmed. The feasibility and reliability of the optimizing design schemes put forward above are proved ulteriorly by test validating. The gained schemes not only have good design uniformity and little ammunition wastage and meet the test demand, but also have better forecast ability for the result data of other points using the mathematic models from the actual test points.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Design of Non-fragile Satisfactory Estimator for Linear Continuous Perturbed Stochastic Systems

The design problem of non-fragile estimator is addressed for a class of perturbed linear continuous systems. The perturbations occur on the plant and estimator parameters. The estimator designed should force the error system to achieve the desired decay rate and force the steady error variance less than the specified upper bound irrdevancy of the admissible plant perturbations and estimator perturbations. Consistency problem of the decay rate with the variance upper bound is first considered via linear matrix inequality （LMI） approach. The solution of the estimator parameter under specifications to be consistent is then discussed. The consistency condition of specifications and estimator parameter solution are transformed to feasible or minimum problems subject to a set of LMI respectively. The method is illustrated by a numerical example.     

An Improved Scene-based Nonuniformity Correction Algorithm for Infrared Focal Plane Arrays Using Neural Networks

The improved scene-based adaptive nonuniformity correction （NUC） algorithms using a neural network （NNT） approach for infrared image sequences are presented and analyzed. The retlna-like neural networks using steepest descent model was the first proposed infrared focal plane arrays （IRFPA） nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term, regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper, the local median filtering result of Xij （ n ） is proposed as an alternative value of desired network output of neuron Xij （ n ）, denoted as Tij （ n ）, which is the local spatial average of Xij （ n ） in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence. Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach, especially for the short-time image sequences （several hundred frames） subjected to the dense impulse noises with a number of dead or saturated pixels.     

Piecewise Filter of Infrared Image Based on Moment Theory

The disadvantages of IR images mostly include high noise, blurry edge and so on. The characteristics make the existent smoothing methods ineffective in preserving edge, To solve this problem, a piecewise moment filter （PMF） is put forward. By using moment and piecewise linear theory, the filter can preserve edge. Based on the statistical model of random noise, a related-coefficient method is presented to estimate the variance of noise. The edge region and model are then detected by the estimated variance. The expectation of first-order derivatives is used in getting the reliable offset of edge. At last, a fast moment filter of double-stair edge model is used to gain the piecewise smoothing results and reduce the calculation. The experimental result shows that the new method has a better capability than other methods in suppressing noise and preserving edge.     

Bistatic Sonar Localization Based on Best Linear Unbiased Estimation

A best linear unbiased estimation （BLUE） algorithm for bistatic sonar localization is proposed. The Cramer-Rao bound for bistatic Sonar and the geometrical dilution of precision （GDOP） in different conditions are given. The simulation results show that the location accuracy of BLUE algorithm is higher than the weighted least square method.     

Research on Gear-broken Fault Diagnosis in a Tank Gearbox

A fault diagnosis method of working position gear in a tank gearbox is put forward based on simulating the fault of working position gear in an actual tank, extracting the envelope of vibration signal by Hilbert transformation amplitude demodulation method, and zooming the low-frequency band to envelope signal.