采用数值模拟方法研究了双箭头负泊松比多胞结构抗子弹侵彻性能,对比分析了顶边撞击、铰点撞击、侧边撞击三种弹靶作用条件下子弹的侵彻行为与双箭头负泊松比结构的破坏形式.研究结果表明:当子弹以较高速度撞击双箭头负泊松比结构时,该结构的负泊松比效应不显著;顶边撞击与铰点撞击时,子弹直接贯穿结构,胞元破坏较小,此时双箭头负泊松比多胞结构抗侵彻性能较差;侧边撞击时,子弹未贯穿多胞结构,胞元破坏较大,双箭头负泊松比结构依靠其双三角结构使子弹发生偏转,显著增大了其侵彻阻力.分析了顶边撞击时子弹的入射角度变化对于双箭头负泊松比结构抗侵彻性能的影响,发现存在30°入射角和60°入射角.当子弹处于这两种入射角附近时,双箭头负泊松比多胞结构具有一定的抗侵彻能力.

重载导弹发射车多使用4 轴连通式双气室油气悬架,为了研究其连通耦合效应,以便对发射车设计进行参考.在2 轴连通式油气悬架数学模型的基础上,基于AMESim软件分别建立2 轴/4 轴连通式双气室油气悬架系统的仿真模型,在几种不同信号频率与相位激励下分析了多轴连通式双气室油气悬架系统的连通耦合效应影响.结果表明:连通式油气悬架在低频激励作用下具有明显的阻尼特性.4 轴连通式悬架系统与2 轴连通式悬架系统相比,其外特性具备明显优势.连通式油气悬架系统受低频激励时外特性表现比较激烈,而在受高频激励时外特性表现良好,这说明系统在处于高频环境时更能衰减系统的不同步振动.

为简化制作工艺,将碳纤维增强环氧树脂复合材料(CFRP)六边形管采用环氧树脂胶粘接在一起形成碳纤维增强环氧树脂复合材料六边形管多胞结构(Multicellular structure of CFRP hexagonal tubes,MSCHT).通过对多胞结构进行准静态压缩试验,分析了其压缩破坏模式和耗能特性,并获取了各影响因素对压缩响应的贡献率.研究结果表明:多胞结构均呈现出渐进压缩破坏模式,沿着六边形管自由面形成带状纤维束;相邻碳管间的相互作用和粘接面的存在导致多胞结构的实际平均载荷高于其比测值,进而使得实际耗能量高于耗能量比测值;与单根六边形碳管相比,MSCHT的比吸能更高,并且存在最优壁厚使得结构比吸能最大,本次试验试件的最大比吸能达到114.4 kJ/kg;多胞结构的胞元数量和壁厚对平均压缩载荷、峰值载荷、耗能量的线性贡献率均为正且胞元数量贡献率高于壁厚,而壁厚对比吸能的线性贡献率为负,胞元数量对比吸能的贡献率为正.

无杆式高压气动弹射器因开口的固有结构决定其存在一定量的泄漏,为此设计并开展样机泄漏测试试验.基于由实验数据拟合的标准干空气热力学状态方程,分别按理想气体和真实气体对比计算泄漏率,并拟合泄漏率随压力、行程变化的经验公式.建立考虑动态泄漏、真实气体效应及真实开阀规律的精确内弹道模型,对考虑和不考虑泄漏两种工况的结果进行对比,并详细分析考虑泄漏的弹射过程中热力学参数与负载运动参数的变化规律,将其与弹射试验数据、流体仿真结果进行对比.研究结果表明:按理想气体计算的泄漏率比真实气体偏小约 4%;泄漏率不超过4%/s;考虑泄漏的精确内弹道模型计算结果与弹射试验数据、流体仿真结果均基本一致,具有较高的计算精度.

In this paper, a kind of electromagnetic blocking device of simulated projectile based on rodless cylinder ejection is designed. The characteristic of the device is that only permanent magnet is used as the magnetic field source, and eddy current is generated by the circular cutting magnetic field on the simulated projectile, so as to slow down the simulated projectile. According to Maxwell simulation calculation, when the thickness of permanent magnet is 200mm, axial magnetization and reverse arrangement are adopted, the simulated projectile with initial velocity of 20m/s and mass of 200kg can be slowed down to 0m/s in 275ms, and the displacement of simulated projectile at this time is 2457mm. In the actual situation, due to friction and other reasons, The simulated spring deceleration displacement is smaller than the simulated value.

Adding a basalt fiber layer (BF) to carbon-Fiber-reinforced plastic (CFRP) material can effectively improve its extensibility. In the work described in this study, a study of hybrid layup BF and CFRP (BCFRP) compressive performance and strain-rate effect was conducted. Through quasistatic loading experiment and split Hopkinson pressure bar experiments, the stress–strain relationship of BCFRP specimens at different strain rates was obtained, and the rate-dependent constitutive equation with only average strain-rate parameters. Depending on the form of failure, the range of average strain rates to which this constitutive equation applies can be determined. Results show that the failure strain of BCFRP under quasistatic conditions is 45% higher than that of CFRP; its failure mode is related to the strain rate. As the average strain rate increases, the main failure mode of the specimen changes from delamination and matrix fracture to fiber fracture failure. The strain rate-dependent constitutive equation has a high degree of fitting to the experimental results, and the single-parameter rate-dependent constitutive equation has good prediction accuracy for the experimental results, with the maximum error being 6.13%.

无杆式高压气动弹射器因开口的固有结构决定其存在一定量的泄漏，为此设计并开展了样机泄漏测试试验。基于由实验数据拟合的标准干空气热力学状态方程，分别按理想气体和真实气体对比计算泄漏率，并拟合泄漏率随压力、行程变化的经验公式。建立考虑动态泄漏、真实气体效应及真实开阀规律的精确内弹道模型，对考虑和不考虑泄露两种工况的结果进行对比，并详细分析考虑泄露的弹射过程中热力学参数与负载运动参数的变化规律，将其与弹射试验数据、流体仿真结果进行对比。研究结果表明:按理想气体计算的泄漏率比真实气体的偏小约4%；泄漏率不超过4%/s；考虑泄漏的精确内弹道模型计算结果与弹射试验数据、流体仿真结果均基本一致，具有较高的计算精度。

道路结构作为承载基础,与发射装备构成了动力耦合系统,冲击载荷作用下路面的响应特性将直接影响到导弹发射安全性.为研究多次弹射载荷下水泥混凝土道路结构的动态响应,以压缩空气为动力源搭建模拟弹射载荷生成装置,在三维试槽中铺筑水泥混凝土路面,面层中铺设应变传感器,土基中埋设土压力传感器,通过多次冲击加载试验获取模拟弹射载荷作用下土基压应力和面层应变变化规律,分析土基内压应力与深度及载荷作用面中心点距离间的关系,得到多次模拟弹射载荷下面层破坏形式及破坏机理.研究结果表明:冲击压力与土基峰值压应力呈线性关系;距离载荷中心点3300 mm处,不同模拟弹射载荷下各深度处的土基压应力峰值已经非常小,模拟弹射载荷的径向影响范围为3300 mm以内;模拟弹射载荷较小时面层为弹性变形,模拟弹射载荷增加到0.77 MPa时混凝土面层产生辐射状贯穿裂缝;弹射载荷作用下路面出现整体沉降.

行驶性能和通过性能是评估车辆越野性能的基本指标.为得到八轴连通式油气悬架车辆的越野性能,分别对行驶性能和通过性能开展了研究.简化了整车的物理模型,根据拉格朗日方程推导了车辆的振动方程,建立了白噪声路面输入方程;通过仿真结果与实验结果的对比,验证了柔性模型的合理性.基于柔性模型,以路面不平度系数为输入变量,得到了车辆在较好路面、一般路面、较差路面、恶劣路面的行驶性能;通过建立脉冲冲击、台阶冲击、震荡冲击的数学模型,得到了车辆的通过性能.结果表明:随着路面等级变差,八轴车辆的极限车速下降,B级路面极限速度为144 km/h,C级路面极限速度为64.8 km/h,D级路面极限速度为32.4 km/h,E级路面极限速度为7.2 km/h;路面冲击类型主要影响车头的加速度和车轮相对动载的极值,脉冲冲击时车轮发生腾空,且车头垂向加速度超过2.5倍重力加速度,而台阶冲击和震荡冲击均未出现轮胎腾空和车头2.5倍重力加速度的过载.

In view of the deficiency of the existing research on the energy absorption characteristics of composite multi-cell structures, a kind of multicellular filling structure (MFS) was proposed, which was filled by some single small-size CFRP tubes (SCT) into large-size CFRP tubes. The quasi-static compression tests of SCT and MFS were carried out, which included full stroke compression and multi-staged compression, then the failure mode and energy absorption characteristics were analyzed. The results show that the failure mode of the outermost CFRP tube of MFS is similar to SCTs, and there is no obvious difference between full stroke compression and multi-staged compression, but the radial deformation of the outermost tube is obvious due to the compression of the inner tube and debris. Compared with the full stroke compression process, the total energy absorption of SCT and MFS is more when they are multi-staged compressed. In this study, the maximum specific energy absorption (SEA) of SCT is 86.0 J/g and the minimum SEA is 59.3 J/g. While, due to the low SEA of the outermost tube of filled structures, the SEA of the MFS is between 69.8 J/g and 75.9 J/g, which is less than the maximum SEA of SCT. The SEA of the MFS is higher than that of SCT with appropriate external constraint and internal carbon tube number by further research.

为研究某型导弹冷发射装备的场坪适应性,找到影响发射装备场坪适应性的影响因素和评价指标,推导出场坪垂向刚度和风载荷两个重要影响因素的计算方法,确定影响因素取值范围.基于此,采用优化拉丁超立方试验设计方法生成试验样本点.利用有限元数值模型对发射装备的动力响应进行大子样仿真分析,获得样本点空间内导弹出筒时的角位移和角速度,并选择径向基神经网络法建立导弹出筒姿态近似模型,分析导弹出筒姿态敏感度.在敏感度分析的基础上,给出考虑多个因子共同作用下的场坪适应性综合判据,为发射装备的场坪适应性评估提供参考.通过分析可知,当风速不大于2.5 m/s,路面纵坡不大于1.2°时,该发射装备在4级沥青路面即可满足该型导弹发射要求,说明其具有良好的场坪适应性.

本文以军工类专业《兵器发射理论与技术》为例,结合当前军工专业人才培养方式与需求,探索军工专业实验平台建设与教学的手段、方案.对当前军工专业实验与教学过程中存在的实验规模小、平台集成度低、实验内容陈旧、教学方法单一、学生实践内容少、考核方式不科学等问题进行了总结,在实验平台建设、教学方法创新、实验教学内容等方面提出了完善和改进建议,教学效果跟踪表明,完善和改进建议具有较好成效.

As the lubrication performance of sealing structures in rodless open cylinders varies with sliding velocity, the concept of a critical velocity is proposed based on the aforementioned characteristics and the lubrication performance of sealing structure is analysed. A finite-element model of sealing structure is established and the oil film load under dynamic lubrication condition is obtained. A two-dimensional theoretical model of lubrication performance in sealing structure is established based on the proposed critical velocity. The influence on critical velocity of parameters including pre-compression, geometry size and microscopic morphology is analysed. Considering surface microscopic morphology, generation of heat by friction, heat flux distribution and other factors, a three-dimensional numerical model of lubrication performance of sealing structure is established to reveal the influence of texture mechanism on lubrication performance. As concluded, with the increase of pre-compression, the lip angle and the temperature of lubrication oil, the critical velocity increases. The three-dimensional microscopic morphology of seal ring is found to pose obvious influence on critical velocity, and the isotropic microscopic morphology tends to form total lubrication under the same conditions.

提出了一种描述导弹适配器新型基体材料PU2531在不同温度和不同应变率下的热-粘-超弹本构模型.利用准静态单轴压缩实验装置和分离式霍普金森压杆(SHPB)装置,获得不同温度不同应变率下的聚氨酯弹性体的压缩应力-应变响应规律;建立了聚氨酯弹性体材料含温度效应项的粘-超弹本构模型,根据实验结果拟合了本构模型中的相关参数;编写了用户子程序VUMAT,单轴压缩实验结果与数值解模型结果吻合度较高,验证了所建立的本构模型及用户子程序的有效性.

电液位置伺服系统存在高频干扰和传感器测量噪声,导致传统自适应控制参数收敛性差、性能一致性低等问题.针对这些问题,提出一种基于低频学习的鲁棒控制策略.设计低通滤波器修正电液位置伺服系统的自适应参数,将修正前后出现的残差反馈到鲁棒自适应控制中构造新型控制律,滤除自适应律中存在的高频成分,从而有效地降低参数的波动程度,达到稳定收敛的目的.通过Lyapunov稳定性理论验证了闭环系统的全局稳定性.对比实验结果表明,所提方法能够有效解决电液位置伺服系统在高频干扰和传感器测量噪声作用下的参数稳定收敛问题,同时获得了系统动态误差的渐进稳定性,实验取得了预期效果.

为了验证本文所采用的方法对射流啸叫单音特性的预测能力,针对不同马赫数下射流流场进行了数值模拟.采用SAS-SST模型模拟二维轴对称超声速欠膨胀射流的湍流流场,空间离散采用Roe格式,时间离散采用双时间步长法,远场边界采用无反射边界条件.模拟了激波单元结构形成过程,并对比了实验和计算所得的流场纹影图、不同位置上的压力和密度值;对于射流噪声,研究了啸叫单音的波长、频率和声压级,这些数据都与实验值吻合良好,并且可以准确的捕捉到啸叫单音的模态切换.此外,当考虑有来流条件下时,啸叫噪声幅值降低,有利于削弱了射流对附近机械机构的声疲劳破坏.结果 表明,该方法可用于啸叫单音预测和机理研究,为下一步高马赫数射流啸叫单音和减小啸叫单音的研究提供了重要参考.

Despite abundant finite element analysis (FEA) of low velocity impact (LVI) performance of composite laminates, the questions regarding the effects of different load reversal damage laws on predicted impact responses of composite laminates and which one is preferred for more physically-sound simulation of laminate LVI responses remain unresolved. In this paper, an elasto-plastic progressive damage model based on three load reversal damage laws including coupled tension-compression law, semi-stiffness recovery law and full-stiffness recovery law, were numerically implemented in predicting laminate LVI responses. By comparisons between simulations and available experimental data, the influences of different load reversal damage laws on predicted delamination threshold load, impact force, laminate central deformation, dissipated impact energy as well as damage status were analyzed. More accurately predicting laminates’ LVI responses, the semi-stiffness recovery law was concluded as the preferred intralaminar load reversal damage law.

The low-velocity impact response of the sandwich curved panels with functionally graded carbon-nanotube-reinforced composite (FG-CNTRC) surface and isotropic foam core is discussed in this paper.Five types of stacking arrangements including uniform distribution of FG-CNTRC considering thermal environment were analysed. Using the Hertz contact law and rule of mixture model as well as the Kármán-type equations, the nonlinear formulations were built and solved by the two-step perturbation method. The carbon nanotubes’ volume fraction, the structure size, the original impact velocity, temperature, relative thickness and the influence of gradient forms on the panels’ impact behaviours were analysed. The outcomes show that the stiffness of the non-contact surface has large influence on contact response and various types of FG-CNTRC can be used for different operating conditions providing stiffness or cushion performance.

A model reference robust adaptive control method is proposed for electro-hydraulic servo system with the consideration of model uncertainty and state constraints.The approximation model of electro-hydraulic servo system is first taken as the design object of model predictive controller (MPC).The constrained desired states,which are thought as the reference signals of the subsequent servo control design,will be generated in the design of MPC.In order to overcome various model uncertainties in the hydraulic system,a robust adaptive controller (RAC) is designed based on the backstepping method,and it achieves state constrained control of hydraulic systems with various model uncertainties.The asymptotic stability of closed-loop system is proved via the Lyapunov stability theory.The simulation results show that the proposed controller has strong robustness against various model uncertainties and achieves specific constraints of the specified states effectively,which verifies the effectiveness of the proposed control strategy.

针对多缸承载平台的高精度快速调平问题,综合考虑多个活塞缸驱动承载平台系统中的偏心矩、缸内摩擦、泄漏的不确定性及油液缓慢时变特性,提出将多级自适应控制与动态控制分配相结合,保证平台质心位置不变实现高精度快速调平.对活塞缸存在的输出力约束及调平过驱动问题,采用能量最小化且考虑输入约束的动态控制分配方法,并以有效集算法进行求解,实现各活塞缸受力的合理分配.车载快速调平仿真实例表明,所设计的控制器能有效实现车载平台的高精度快速调平.该控制策略为解决多活塞缸驱动承载平台的调平控制问题提供了理论依据及实践参考.