破甲/杀伤多用途战斗部结构设计及试验研究

为使战斗部能够打击多种目标,在保持原单兵破甲战斗部的质量、外形结构和破甲威力基本不变的条件下,利用新型薄型波形控制器、半预制壳体和精密破甲战斗部技术,设计了破甲/杀伤多用途战斗部。采用射流垂直穿深试验、射流大间隔靶和破片杀伤试验,研究了改进后单兵破甲弹的射流穿深和破片杀伤威力。结果表明,设计的多用途战斗部在大炸高下使射流侵彻带前挂板加厚度80mm/50°均质靶后,还可穿透不低于3块厚度10mm的Q235靶板。周向杀伤破片能穿透距爆心5~10m处厚度1.5mm的Q235鉴证钢板,破片密度不小于2枚/m2,实现战斗部多功能的打击需求。     

六棱柱形战斗部预制破片驱动的数值模拟与试验

为研究六棱柱形战斗部预制破片的杀伤效果,建立了正六棱柱战斗部的三维模型,并以等高、等外径的普通圆柱形战斗部为对照组,利用LS-DYNA软件分别模拟了二者在端面中心起爆与偏心两线起爆时对破片的驱动过程,分析了破片的速度与密度增益,并设计了实弹试验对模拟结果进行了验证。模拟结果表明,偏心两线起爆时,六棱柱形战斗部和圆柱形战斗部破片速度的增益分别为9.2%和12.2%,与试验值的误差均在10%以内。试验结果表明,与端面中心起爆的圆柱形战斗部相比,六棱柱形战斗部在端面中心起爆和偏心两线起爆时分别可使破片密度提高53.6%和74.1%,且使破片在较远距离处仍有较优的聚集效果。     

动态线列式破片战斗部技术探索

依据现代战争对反导技术的迫切需求,提出了一种动态线列式破片战斗部技术,在弹目动态交汇条件下使目标形成线列式穿孔,同时使穿孔周边产生撕裂效应和应力集中效应,从而对高速飞行的导弹等目标实施线切割式高效结构毁伤.结合动态线列式破片战斗部设计原理,给出了该类战斗部系统设计方法和主要设计参数的工程计算公式,通过数值模拟和原理样机...     

炸药驱动预制破片轴向抛掷速度规律研究

为解决爆轰产物对轴向预制破片的作用压力从柱状装药中心沿径向逐渐降低,从而导致轴向预制破片抛掷速度沿径向逐渐变小的问题,研究了柱状装药长径比与装药壳体厚度等装药结构参数对轴向预制破片抛掷速度沿径向分布规律的影响,针对某种轴向前置预制破片战斗部,进行了破片轴向抛掷速度沿径向分布规律的试验.结果表明,装药长径比以及装药壳体等装药结构参数对轴向预制破片抛掷速度影响较大,通过装药尺寸、壳体厚度等参数匹配,可以调整轴向预制破片的抛掷速度.     

套筒材料与壁厚对跳弹威力的影响研究

为了克服普通榴弹杀伤效果差,容易形成死角的缺陷,本文根据跳炸杀伤战斗部的结构特点,采用非线性动力程序ANSYS/LS-DYNA软件对破片套筒进行仿真计算,以确定使战斗部威力达到最大时的套筒材料和最佳壁厚。仿真结果表明:当套筒壁厚为1.5mm时,预制破片初速为最大;当套筒材料为45#钢时,预制破片初速显著提高。     

周向液体层对战斗部破片加速过程的影响

为研究外部液体介质对杀伤战斗部破片加速过程的影响,设计了液体层厚度与装药直径之比为1∶1的模拟样机,开展了满腔、半满和空腔3种状态下的模拟样机静爆试验,得到周向液体层包覆下战斗部的破片速度,并利用LS-DYNA软件对3种状态下装药加速破片的过程进行了分析,与试验结果进行了对比。结果表明,外部液体介质影响了战斗部装药爆轰能量的分配,进而降低了装药加载破片的性能,在满腔状态下破片的速度仅能达到空腔状态下的55%~60%;半满状态时,水介质的径向惯性约束作用使得爆轰产物并未均等地向各个方向膨胀作功,而是向无水方向流动较快(类似于局部泄爆),其能量出现不均衡分配,进而有效提高了无水一侧破片的速度,达到空腔状态下的1.65倍。数值模拟的结果与实验结果相吻合,进一步验证了周向液体层对战斗部破片加速过程的影响。     

不同破片对模拟战斗部的毁伤实验研究

通过战斗部所产生的几种不同形状的破片对不同模拟战斗部的作用,研究了模拟战斗部在不同的打击动能和冲击波超压条件下的毁伤情况。实验结果表明,仅靠冲击波超压几乎不能毁伤如巡航导弹这样的战斗部,常规战斗部也很难引爆巡航导弹战斗部。反导导弹战斗部工程设计要从破片初速、密度和质量三方面综合考虑,才能有效击毁巡航导弹。     

爆轰波压力测量与战斗部设计的关系

一、概论战斗部主要分为核战斗部和常规化爆战斗部两种。本文只讲常规战斗部所涉及应用爆压问题。根据战斗部的作用大致可分为以金属为载能体的战斗部,如地对空或空对空战斗部是以方形破片或杆式破片杀伤飞机;又如以聚能罩形成金属超高速射流的反坦克导弹战斗部或自锻成型的翻转罩反坦克破甲弹或反舰艇战斗部,以及以爆破为目的的地对舰或地对地战斗     

爆轰波压力测量与战斗部设计的关系

一、概论战斗部主要分为核战斗部和常规化爆战斗部两种。本文只讲常规战斗部所涉及应用爆压问题。根据战斗部的作用大致可分为以金属为载能体的战斗部,如地对空或空对空战斗部是以方形破片或杆式破片杀伤飞机;又如以聚能罩形成金属超高速射流的反坦克导弹战斗部或自锻成型的翻转罩反坦克破甲弹或反舰艇战斗部,以及以爆破为目的的地对舰或地对地战斗     

定向战斗部破片能量增益的数值模拟

利用有限元分析计算方法分别对爆炸网络控制定向战斗部和中心起爆战斗部装药驱动破片过程进行了研究,得到该过程的动画演示过程和各种相关数据。通过对数值模拟数据的处理,得到爆炸网络控制定向战斗部破片速度和数目的分布规律以及爆炸网络控制定向战斗部相对于中心起爆战斗部在增益区内的破片速度增益、数目增益和能量增益结果。     

超声波对鳞片状石墨的粉碎作用及结构影响

本文采用频率为20kHz的探头式超声波反应器,研究了超声波对水中鳞片状石墨的粉碎作用.发现超声波粉碎是一种冲击作用机制,既有空化冲击波产生的表面破碎作用,也有微射流产生的体积破碎作用.XRD分析表明超声粉碎后石墨的晶体结构发生了变化,其(002)衍射峰位向高2θ角方向偏移,即相应晶面面间距变小.     

肉桂原花青素的片段化研究

采用食物来源的茶多酚为亲核试剂对肉桂中原花青素多聚体(PPC)进行片段化反应,采用大孔吸附树脂HP-20对片段化反应产物进行分级处理,使低聚体从片段化反应产物中分离出来。以反应后低聚体含量和低聚体中原花青素含量为考察指标,通过单因素试验、正交试验考察了片段化反应时间、反应温度、盐酸体积分数和多聚体与茶多酚物料比对反应的影响。结果表明,各因素对反应的影响次序为:盐酸体积分数 > 多聚体与茶多酚物料比 > 反应温度 > 反应时间,片段化反应最佳条件为:反应温度为50 ℃、反应时间为60 min、盐酸体积分数为1%、多聚体与茶多酚物料比为1:1,在此条件下,得到片段化反应后低聚体含量为65.26%,低聚体中原花青素含量为75.28%。     

Morphological influences in the gas phase polymerization of ethylene by silica supported chromium oxide catalysts

Dramatic changes occur during the initial stages of olefin polymerization over heterogenous catalysts. As polymer accumulates, the catalyst fragments and the void space within the growing particle becomes filled with polymer. The changing monomer transport rate to the active sites, dissipation of heat and stress with the particle, and eventually, dispersion of catalyst fragments within the growing particle can control the polymerization. We focus on the changes in, and influence of, polymer, catalyst and void morphology during the nascent polymerization for silica supported chromium oxide catalysts. We find that the course of the polymerization depends on the initial stages yet is seldom considered in polymerization models. We review several years of morphological characterization that identify the important physical phenomena which occur during nascent heterogeneous olefin polymerization.     

A population model of quartzite particles in a lab-scale fluidized bed due to the thermal fragmentation

A population model has been developed to simulate the size distribution of quartzite particles in a lab-scale fluidized bed. While quartzite particles as a kind of bed materials in the differential density circulating fluidized bed were loaded into the high temperature bed, the size distribution of quartzite particles would be changed due to the thermal fragmentation, which could significantly influence fluidization characteristics and heat transfer.With the purpose of comprehending the population of quartzite particles after thermal fragmentation, a fragmentation experiment of quartzite particles has been carried out in a lab-scale circulating fluidized bed. The results show that the fragmentation of particles mainly occurred on particles surface. Based on this experimental phenomenon, a mathematical population model was established to estimate the particle size distribution. The predicted value from the population model is close to the experimental value.     

Evolution of the metal microstructure and conditions of strain localization under high-strain-rate loading

Specific features of evolution of the microstructure of coarse-grained and fine-grained copper are examined on the basis of an available dependence of the critical parameters of strain localization on the grain size, which was derived in an explosive collapse of hollow thick-walled cylinders. Similarity of the properties and mechanisms of deformation of fine-grained and ultrafine-grained materials is established. Based on the analysis of the results obtained, a scenario of the change in deformation mechanisms of fine-grained copper in the course of the development of deformation structures under high-strain-rate loading is proposed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 3, pp. 121–131, May–June, 2006.     

Synthetic Applications and Methodological Developments of Donor−Acceptor Cyclopropanes and Related Compounds

Donor−acceptor cyclopropanes are convenient precursors to reactive and versatile 1,3-dipoles, and have found application in the synthesis of a variety of carbo- and heterocyclic scaffolds. This perspective review details our laboratory's use of donor−acceptor cyclopropanes as intermediates toward the total synthesis of various natural products. We also discuss our work in the development of novel cycloadditions and rearrangements of donor−acceptor cyclopropanes and aziridines, as well as an example of an aryne insertion proceeding via fragmentation of a transient donor−acceptor cyclobutane.     

Enzymatic Synthesis Assisted Discovery of Proline-Rich Macrocyclic Peptides in Marine Sponges

Proline-rich macrocyclic peptides (PRMPs) are natural products present in geographically and phylogenetically dispersed marine sponges. The large diversity and low abundance of PRMPs in sponge metabolomes precludes isolation and structure elucidation of each individual PRMP congener. Here, using standards developed via biomimetic enzymatic synthesis of PRMPs, a mass spectrometry-based workflow to sequence PRMPs was developed and validated to reveal that the diversity of PRMPs in marine sponges is much greater than that has been realized by natural product isolation-based strategies. Findings are placed in the context of diversity-oriented transamidative macrocyclization of peptide substrates in sponge holobionts.     

Quasi-static confined uniaxial compaction of granular alumina and boron carbide observing the particle size effects

The quasi-static confined uniaxial compaction of granular alumina and boron carbide was studied, and the effect of triaxial stress on the materials as a function of increasing particle size was observed. The average particle sizes studied for granular alumina were 170 ± 63, 230 ± 55, 330 ± 67, and 450 ± 83 µm. The average particle size studied for granular boron carbide were 170 ± 40, 190 ± 34, 320 ± 59, and 470 ± 90 µm. The material response at hydrostatic pressure as a function of porosity, the bulk modulus as a function of hydrostatic pressure, and the transmission ratio as a function of applied load was evaluated for increasing particle size. For alumina, the increase in particle size resulted in an increase in strength for a fixed porosity, the bulk modulus of this material did not show clear particle size-dependent trends, and the transmission ratio increased with increase in particle size. Conversely, for granular boron carbide, the hydrostatic pressure-porosity curve shifted to the right with increasing particle size, the change in bulk modulus increased with increasing particle size, and no clear particle size-dependent trends were observed when looking at the transmission ratio during the experiment. Post-experiment scanning electron microscopy revealed that alumina powder fragmented from elongated shapes to block-like structures, while boron carbide powder appeared more circular before the experiments and fragmented into smaller comminuted pieces. This paper discusses the implication of the work in the context of the limited experimental data in the field and the modeling of granular advanced ceramics behavior.