Damage of multi-layer spaced metallic target plates impacted by radial layered PELE

Three different kinds of PELE(the penetrator with lateral efficiency) were launched by ballistic artillery to impact the multi-layer spaced metal target plates.The lmpact velocities of the projectiles were measured by the velocity measuring system.The damage degree and process of each laye r of target plate impacted by the three kinds of projectiles were analyzed.The experimental results show that all the three kinds of projectiles have the effect of expanding holes on the multi-layer spaced metal target plates.For the normal structure PELE(without layered) with tungsten alloy jacket and the radial layered PELE with tungsten alloy jacket,the diameters of holes on the seco nd layer of plates are 3.36 times and 3.76 times of the diameter of the projectile,re spectively.For radial layered PELE with W/Zr-based amorphous composite jacket,due to the large number of tungsten wires dispersed after the impact,the diameter of the holes on the four-layer spaced plates can reach 2.4 times,3.04 times,5.36 times and 2.68 times of the diameter of the projectile.Besides,the normal structure PELE with tungsten alloy jacket and the radial layered PELE whit tungsten alloy jacket formed a large number of fragments impact marks on the third target plate.Although the number of fragments penetrating the third target plate is not as large as that of the normal structure PELE,the area of dispersion of fragments impact craters on the third target plate is larger by the radial layered PELE.The radial layered PELE with W/Zr-based amorphous composite jacket released a lot of heat energy due to the impact of the matrix material,and formed a large area of ablation marks on the last three target plates.

弯曲受力状态下钢箱梁钢板极限承载性能仿真

装配式钢箱梁节点承载性能受到多种内力和外力的影响,如节点自重、荷载、支座反力等,导致其极限承载性能仿真难度大。因此,提出一种基于粒子群优化(Particle Swarm Optimization,PSO)算法的装配式钢箱梁节点承载性能仿真。根据当钢箱梁节点存在外力时钢板会出现弯曲受力状态的特点,以钢箱梁钢板厚度、构件横截面以及弯曲刚度为对象,计算节点处于弯曲受力状态时三种参数的数值变化,采用滞回循环分析方法求解受力状态下钢板能耗变化。通过PSO改进粒子群优化算法建立全局目标搜索空间,将钢箱梁节点看作是粒子,设定影响节点承载性能参数点,建立钢箱梁节点受力模型,代入影响结果实现钢箱梁节点极限承载性能仿真。实验结果表明,所提方法可有效分析钢箱梁节点极限承载性能变化和受力状态,仿真精度高、效果好。

撞击姿态对构型弹体非正侵彻多层间隔钢靶弹道特性的影响规律

为深入认识构型弹体非正侵彻多层间隔靶板的弹道偏转规律,结合数值模拟和理论分析,研究了构型弹体在不同撞击姿态下侵彻多层间隔钢靶的弹道特性,其中引入弹体侧向接触力和侧向偏转力矩等参量,着重分析撞击着角和攻角对弹道特性的影响规律。结果表明:构型弹体非正侵彻过程中,在纵向发生阶梯式速度衰减,但变化较小;同时,由于穿靶过程中受到侧向接触力及其偏转力矩的作用,在侧向产生显著弹道偏转。撞击着角决定弹体所受外载荷的非对称程度,着角越大,弹体偏转越严重;撞击攻角则主要影响弹肩穿靶时的径向速度和弹尾穿靶时的触靶位置,二者共同影响弹道轨迹,因而存在使弹体偏转程度发生转折的临界攻角。相比于侵彻单层靶,构型弹体非正侵彻多层间隔靶板的显著特点为弹道偏转存在累积效应,且侵彻前一靶板的弹道偏转情况显著影响到侵彻后一靶板时的弹靶作用特征,进而导致弹道偏转与弹靶接触力互相耦合。相关研究对预测构型弹体侵彻多层间隔靶板性能、优化弹体构型和撞击姿态等具有较好的指导价值。

弹体斜侵彻多层间隔钢靶的弹道特性

为分析弹体斜侵彻多层间隔靶的弹道特性,开展典型卵形弹体不同入射角侵彻多层间隔钢靶试验和数值模拟研究。利用有限元软件LS-DYNA建立弹体斜侵彻多层间隔钢靶数值仿真模型,分析弹体斜侵彻多层间隔钢靶作用过程,得出弹体入射角、弹体速度、靶体厚度及弹体变形对多层钢靶侵彻弹道特性的影响规律并进行了试验验证。结果表明:弹体入射角越大,侵彻弹道偏转越大;初始速度越大,弹体斜侵彻多层间隔钢靶偏转角度越小,且速度对偏转角的影响幅度随速度增大呈减小趋势;随着靶体厚度增加,弹体斜侵彻多层间隔钢靶弹道由整体向下偏转转变为整体向上偏转;靶体厚度对偏转角的影响幅度随靶体厚度增大呈增大趋势;刚性弹体斜侵彻多层间隔钢靶弹道偏转角度比变形弹小。

深圳人才园多功能厅钢管空间桁架设计

建筑结构设计是一个综合考虑功能、建筑艺术、强度、制作工艺等各方面要求的交互工作过程,在一个高质量的设计中,所有这些方面必须得到平衡和恰当的考虑。近年来,在中型跨度的展厅、大厅、厂房等公共建筑的屋盖体系设计中,钢管空间桁架以其较优越的结构性能和较美观的建筑外型得到了越来越多的应用。本文以深圳人才园多功能大厅屋盖钢管空间桁架体系为例,从结构布置、内力及变形计算、节点设计及制造安装等诸多方面阐述钢管空间桁架的设计。