计及布尔登效应的身管振动特性研究

弹丸发射过程中身管的振动对射击精度有很大影响,为了掌握身管振动的规律,将身管简化为悬臂梁模型,在此基础上建立了身管横向振动方程,运用模态分析法求解系统动力响应。针对某火炮不同装药量身管振动进行了数值仿真,对不考虑膛内气体对身管作用和考虑膛内气体对身管作用两种情况进行了比较。求解过程中弹丸的位移、速度和加速度均为实际数据。结果表明,静扰度对身管的振动特性有很大影响,静扰度为0时,弹丸初速越高,弹丸出炮口阶段炮口振动幅度越小,膛内气体对身管的作用力能有效减小发射期间身管的振动幅度。     

某新型多身管火炮的膛口流场形成分析

现代高技术条件下的局部战争要求自动炮具有高射速,这为速射火炮发射弹幕带来了新的问题：膛口流场叠加后对后继发射弹丸的扰动效应将严重影响弹丸的运动状态,改变预定的弹幕分布形式,甚至造成火炮射击精度不足,降低作战效能。以某新型火炮为研究对象,应用计算流体力学方法,通过数值仿真,分析其在不同射击条件下的膛口流场特点以及对弹丸运动状态的影响;分别讨论了射速、身管间距、发射时序对膛口流场的形成与发展过程以及对弹丸的受力和运动状态的影响。得出可以通过控制射速和改变身管间距来降低膛口流场对弹丸运动状态的影响。     

基于数值仿真的某型火炮身管设计压力曲线系统分析

火炮身管设计压力曲线给出火炮发射过程中身管各截面承受的最大压力,是设计身管壁厚的依据。高低温压力法只考虑了装药温度变化对膛压的影响,从系统的角度考虑,装药质量、药室增长量、弹丸质量变化也会对膛压造成影响。通过对某型火炮内弹道模型进行数值仿真,分析上述因素变化对膛压和身管设计压力曲线的影响,并给出了各因素综合作用下的身管设计压力曲线。研究表明,装药质量、装药温度和药室增长量变化均对膛压有较大影响;装药质量和装药温度直接影响身管设计压力曲线的组成。     

基于数值仿真的某型火炮身管轴向力系统分析

为精细分析某型火炮身管强度,在身管受力分析基础上,采用数值仿真方法,系统研究了弹丸膛内运动时期身管和弹丸的运动规律,炮膛合力、反后坐装置作用力、膛底作用力、药室锥面作用力、摇架摩擦力、弹丸作用力的变化规律,得到了不同时刻的身管轴向力曲线。研究标明,反后坐装置作用力、弹丸作用力、摇架摩擦力对身管轴向力影响较小,膛底作用力和药室锥面作用力对身管轴向力影响较大,身管凸台面处轴向力最大。     

考虑身管初始挠度的弹炮耦合振动特性分析

为研究火炮发射过程中运动弹丸激励下的身管振动特性,以某型火炮为例,基于Euler-Bernoulli梁理论,建立考虑身管初始挠度的移动弹丸-弹性身管耦合振动方程,利用模态叠加法对方程进行求解。基于有限元软件Abaqus以及动力学分析软件Adams建立相应考虑初始挠度的刚柔耦合动力学模型,并对数值计算的结果进行验证。在模型的基础上,对弹丸速度和弹丸质量影响炮口振动特性的规律进行分析。结果表明对于在运动弹丸激励下身管振动问题,身管初始挠度对振动分析结果的影响很大,不可忽略。在考虑身管初始挠度的情况下,弹丸速度越大,对弯曲身管的校直作用越明显,炮口振动幅值越大;弹丸速度一定时,弹丸质量越大,炮口振动幅值越大。     

弹性身管的弹炮耦合问题研究

建立精确的线膛炮身管与弹丸模型,基于Adams中的柔性体接触理论,在考虑身管弹性的基础上,建立弹带和弹丸前定心部与身管内膛的接触模型,在该软件平台上分别对弹丸与刚性体线膛炮身管、弹丸与弹性化处理的线膛炮身管的弹炮耦合过程进行动力学仿真,得到两组弹炮耦合时的炮口振动及对应的弹丸运动响应数据。将所得数据进行对比,结合以往事实,说明在研究弹炮耦合时考虑身管弹性的重要性。结果表明该动力学模型在一定程度上表征弹丸与身管之间的作用机理,可以为通过减小身管振动的方法来提高射击精度提供理论参考。     

火炮身管胀膛原因浅论

身管胀膛是小概率事故,但在国内外的火炮试制过程中仍时有发生,针对能够引起胀膛的原因进行分析研究,供火炮研制生产借鉴。     

考虑润滑条件的弹带挤进过程有限元分析

以某大口径火炮为研究对象,针对身管内膛有油和无油两种工况,考虑弹带与内膛表面摩擦系数随弹丸速度变化的因素,利用非线性有限元软件ABAQUS,作出简化假设处理,建立弹带挤进膛线过程的计算模型并进行数值模拟。结果表明,挤进过程中弹带受坡膛挤压,凸台材料向后侧环形凹槽流动,同时弹带材料向阴线部流动形成弹带刻槽。在前后弹带开始接触坡膛和最大塑性变形时刻出现弹带与坡膛的接触力极值点。有润滑条件下的挤进过程对应挤进压力小,相应射程也较小,火炮内膛有油条件下易造成首发近弹,在射击准备过程中应进行除油。     

弹药精确装填可靠性分析及测试

为了保证在复杂环境下连续工作的火炮自动装填机构装填参数的一致性,研究了火炮自动装填机构工作的可靠性及其测试方法。首先,分析了装填参数变化对内弹道参数的影响和导致参数变化的原因。然后,设计了多传感器装填参数测试系统,利用该系统对输弹过程和输弹效果进行了综合测试。测试结果表明:在装填开始60ms左右装填机构尾部出现的峰峰值为14mm的振动是影响弹丸入膛姿态并与身管尾端面碰撞的主要原因;当弹丸的挤入压力为3 300～14 000N时,卡膛行程在2mm内变化;根据密集度分布将卡膛行程分为三个区域,其中第二区域1.321～1.557mm为可靠卡膛区。测试表明,所采用测试方法和精度能够满足装填机构的检测要求,可为装填机构的结构优化和性能评估提供数据支撑。     

基于80C196单片机的装甲火炮身管膛温测量系统

装甲火炮在射击过程中高温火药燃气及弹带摩擦的热作用对火炮身管造成了较严重的热影响,如身管内膛烧蚀磨损、身管热应力、身管热弯曲等,热作用的存在不仅影响炮弹的初速、射程、精度等丧失,而且还严重阻止了火炮性能的发挥,因此必须准确地测量炮膛内的温度,从而采取有效的降温措施.基于此文章从传热学的角度对炮膛内的温度分布进行了研究,并应用当今成熟的薄膜热电偶传感器技术、单片机技术,数据采集处理等技术对火炮发射时身管某层面内的瞬态温度进行测量,并由基于外推法编制的软件推算出膛内的温度.实验数据表明该温度是作为降低膛温的有利依据.     

Some scaling laws governing gun erosion

Gun barrel erosion is one of the major problems limiting the velocity, range and accuracy of the projectile. The various interacting mechanisms causing erosion are discussed. The importance of developing scaling laws governing gun tube erosion is emphasized. The approach adopted in this paper for the development of scaling laws is inspired by similar attempts in cavitation and liquid impact erosion. The concepts of threshold erosion, erosion intensity, erosion strength and erosion parameter are extended, modified and applied to gun tube erosion. As a result, the outlook for developing scaling laws governing gun barrel erosion seems very promising. The nondimensional number called the erosion parameter is given by the ratio between the output intensity of erosion representing the energy absorbed by the material and the input intensity of erosion contributed by the erosive forces. The output intensity of erosion is given by the product of the rate of depth of erosion and erosion resistance of the material, whereas the input intensity includes the Poisson's ratio of the projectile, the maximum acceleration, the maximum velocity and the bore diameter. With the aid of a few justifiable assumptions, it has been shown that the rate of depth of erosion is directly proportional to the square of the bore diameter. Available experimental data support these results for velocity scale and size scale. Further experiments are required to test these predictions fully. The erosion state is highly dependent on the number of rounds fired; it has four stages including incubation, acceleration, deceleration and steady state periods very similar to other erosion phenomena. Previously developed erosion theory correlates well with the available gun tube erosion rates as a function of the number of rounds fired; this lends further support to the erosion model proposed in this paper. However, the interacting influences of thermal and chemical mechanisms must be carefully considered in any further developments.     

火炮身管精密加工与在线检测技术研究

火炮身管是火炮的关键零部件,由于其长径比大、要求精度高,它的加工属于深孔精密加工范畴,而国内对此加工的生产水平落后,加工效率低、质量差。火炮身管药室高效精密数控镗床的设计制造满足药室加工多锥段、高精度要求,加工效率较传统工艺提高数倍。该设备能够实现多品种、小批量、高精度加工生产的需求。火炮身管缠度检测原理样机由炮膛爬行器、缠度测头和计算机控制与数据处理系统3部分构成,经检测可实现较低的测量误差。     

转管机枪外弹道特性分析与射表计算软件研究

对某转管武器外弹道特性以及身管旋转对弹道的影响进行了理论分析,并对影响因素加以修正.以弹丸外弹道微分方程为基础建立了转管武器修正的数学模型,对弹丸出膛时的运动速度进行了分析,考虑枪管坐标和地面坐标间的变换,提出了不同转速下身管旋转修正量计算的方法,为转管武器射表编制提供了技术依据.利用MATLAB软件对弹道修正的数学模型进行计算,并编译成为可执行文件,能够直接输出编制射袁所需数据.     

Transverse Motion of a Projectile in the Barrel of a Light-Gas Gun

Means of reducing the transverse load on a projectile accelerating in the barrel of a light-gas gun are considered.     

小口径防空火炮内膛往复振动式气动擦拭机器人设计

针对小口径防空火炮的内膛特殊擦拭要求，进行了往复振动式气动擦拭机器人的机构优化设计与关键技术研究，设计一种往复振动式气动擦拭机器人主机，构建“通用气源+滑块式气动振动器+型号毛刷”的配置架构，在通用空压机供气下，通过更换不同直径毛刷可满足对30mm、35mm和37mm系列小口径来复线炮膛的擦试保养；运用仿真软件进行了关重件的运动仿真和有限元分析，并进行了样机擦拭实验。结果表明，小口径防空火炮内膛往复振动式气动擦拭机器人设计与应用，可提升小口径防空火炮内膛平时和战时擦拭保养能力。     

浅谈火炮身管加工工艺

身管是火炮武器的重要部件,身管制造材料和加工工艺直接影响身管的质量。身管质量严重影响身管寿命,低质身管会导致火炮内弹道性能降低,射击精度下降,制约着武器效能的发挥。深入研究身管问题,分析了身管使用材料发展历程,归纳总结出身管的典型加工工艺,为身管的设计和使用提供参考。     

火炮身管寿命研究

身管是火炮自动武器的重要部件,身管损伤严重影响身管寿命,导致火炮内弹道性能降低,射击精度下降,制约着武器效能的发挥。深入研究身管寿命问题,分析了影响身管寿命的各种因素,归纳总结出身管延寿的主要措施,为身管的设计和使用提供参考。     

考虑身管壁压的迫击炮炮身强度分析

考虑迫击炮在发射过程中膛底和身管内壁压力不断变化的特点,对迫击炮身管和炮尾进行有限元分析。由于身管和炮尾是轴对称结构,故将其简化成二维轴对称平面模型;并根据迫击炮弹在膛内运动的不同时刻,在膛底施加变化的膛压,同时把身管内表面分成22段,分别施加膛压。由此来分析身管和炮尾的强度并给出相应的解决办法。     

Numerical analysis of interior ballistics through eulerian-lagrangian approach

A numerical code for interior ballistics using the Eulerian-Lagrangian approach was developed to analyze polydisperse systems. The internal flows in a gun barrel and the compressibility effects were calculated using the semi-implicit method for pressure-linked equations algorithm. Ghost cell extrapolation was used for the moving boundary with projectile movement. The numerical scheme and moving boundary method were verified through the free piston motion problem. The developed code, including the combustion of the propellant, was compared with simulations of 40 mm gun firings. The results of numerical analysis agree with the simulation results, confirming the reliability of the developed code. Comparative studies were conducted with the results of the interior Ballistics of high-velocity guns code (version 2) according to porosity and propellant size. The numerical analysis of the combustion and movement of individual propellants provides deeper insight into the mechanism of gun firing and the significant factors that influence muzzle velocity.     

Instantaneous Frequency Estimation for Motion Echo Signal of Projectile in Bore Based on Polynomial Chirplet Transform

Microwave interferometer is one of the devices for measuring the movement travel–varying or time-varying velocity of projectile in bore. Microwave interferometer first obtains the Doppler echo signal including the motion information of the projectile in bore, then the velocity is measured based on instantaneous frequency estimation (IFE) of the processed and transformed signal. The parametric time-frequency analysis method can make spectral energy of nonlinear frequency modulation (FM) signal concentrate at some range in the new transform domain. As the motion echo signal of projectile in bore (MSPB) is a nonlinear FM signal, it could be described by polynomial chirplet, one of polynomial FM signal modes, which is used to construct transform kernel for the signal. In this paper, Polynomial chirplet transform (PCT) method is proposed to analyze the simulation and experiment echo signals of projectile in bore. The estimation error and Renyi entropy are used to measure quantify of the time-frequency distribution. Compared with short-time Fourier transform (STFT) method and Wigner-Ville distribution (WVD) method, our results show that the PCT method has most powerful anti-interference performance and highest accuracy of instantaneous frequency estimation for the simulation signal, and lowest Renyi entropy of the instantaneous frequency estimation for the experiment signal. In general, the PCT method has powerful anti-interference performance and high time-frequency concentration and accuracy of instantaneous frequency estimation for the motion echo signal of projectile in bore.