转管机枪开闭锁系统的总体分析设计

目的　探讨转管机枪机心组开闭锁系统的分析设计 ,并保证其布置合理 ,结构简单 ,动作可靠 .方法　在优化机心匣凸轮曲线的基础上 ,通过合理分析机心在开闭锁运动时的回转角 ,确定开锁臂和闭锁臂位置及长度来设计开闭锁系统 .结果　设计出了能满足要求的机心组开闭锁系统 .结论　该方法可用来指导转管武器的机心组开闭锁系统设计     

转管机枪凸轮曲线设计

目的　通过对凸轮曲线过渡段的设计, 减小转管武器机心在曲线过渡段的加速度． 方法　采用由两条正弦曲线和一条二次抛物线组合构成过渡曲线的方法． 结果　确定了过渡曲线的各种参数． 结论　所得过渡曲线可以有效地减小机心在过渡段的加速度     

转管机枪凸轮曲线设计

通过对凸轮曲线过液段的设计,减小转管武器机心在曲线度段的加速度,方法采用由两条正弦曲线和一条二次抛物一组合构成过渡曲线的方法,结果确定了过渡曲线的各种参数。结论所得过渡曲线可以有效地减小机心在过渡段的加速度。     

高速织机中消极式开口凸轮的动力学设计

建立了高速织机中凸轮机构的动力学模型,并简化为单自由度弹性动力学模型;以凸轮轮廓曲线光滑无冲击为目标,构建凸轮开口机构动力学设计模型,进而推导出凸轮轮廓线设计方程.利用该方程对一个实例进行仿真设计,得出了凸轮轮廓设计曲线.得到的高次多项式曲线光滑而无冲击,满足凸轮高速运转时的动力学特性要求,验证了凸轮开口机构动力学设计模型的有效性和正确性.     

新型舰炮供弹凸轮轮廓线设计的研究

采用圆柱滚子直动凸轮机构作为扬弹主动力输出机构,以保证新型舰炮下扬弹机构具有加速性能好、输出动力大、运转机构冲击小等优点。对比常用供弹机构设计曲线,及应用多体动力学软件-ADAMS进行的性能实验表明：样条插值方法设计的凸轮轮廓线具有理想的理论加速度S^..、理论速度S^.、理论跃度J值;增加插值点数目,可以提高曲线的计算精度;有效地解决了在高速、重载条件下凸轮机构刚性冲击和柔性冲击大的突出问题,因而,插值法适合应用于获得不同条件下的预期运动规律曲线的设计。     

摆杆齿条变程器中摆杆凸轮轮廓线综合

介绍了一种活齿传动的演变体摆杆齿条变程器的原理及其运动连续性条件.研究了摆杆凸轮左右两部分理论轮廓曲线方程和实际轮廓曲线方程,并把两组极坐标系中的方程统一于一组极坐标系中.讨论了两轮廓曲线平滑过渡所需条件,为摆杆凸轮轮廓曲线的设计、加工及该机构的进一步研究提供了理论基础.     

基于ADAMS的平底从动件凸轮轮廓曲线设计

使用ADAMS软件反转法设计平底从动件凸轮的轮廓曲线时,由于推杆与凸轮的接触点位置不固定,生成的凸轮轮廓线实际为推杆轮廓的包络线,误差较大。为提高设计精度,将推杆轮廓离散化,利用离散后的多个接触点生成多条曲线并取交集运算,得到了较理想的凸轮轮廓曲线,为ADAMS设计平底从动件凸轮提供新的方法。将生成的凸轮机构进行仿真模拟,与设计目标作比较,探讨离散点个数与设计的精度关系。结果表明:使用离散化方法所设计的凸轮,从动件位移最大误差约为0.207 mm,从动件的推程为20 mm,最大误差比例为1%;误差大部分在0.1 mm范围内,整体误差比例为0.5%;增加离散点个数可以提高凸轮设计的精度。     

基于Adams的凸轮轮廓设计及运动仿真分析

目的基于Adams的凸轮轮廓设计和运动仿真,为凸轮轮廓的设计提供了先进直观的方法,相对于传统的图解法和解析法具有极大的优越性。本文作者通过Adams虚拟样机设计,生成虚拟轨迹曲线并拉伸成凸轮轮廓,同时完成运动参数分析。根据参数分析结果,改变推程运动规律,避免运动中出现刚性冲击。该分析设计方法有助于更加精准的设计出合理的凸轮轮廓。     

用五次PH曲线设计圆盘凸轮轮廓线的研究

针对凸轮轮廓线目前在设计和应用中存在的不足,提出用五次Bézier形式的PH曲线设计对心直动滚子圆盘凸轮理论廓线,使凸轮从动件的运动速度和加速度光滑连续,且在推程、回程的起点、终点处的速度和加速度皆为零,从而极大地改善了从动件的运动特性和动力特性,并且由所得的理论廓线可精确、方便地获得凸轮的实际廓线和数控加工系统中刀具运动轨迹曲线.     

舰炮供弹系统设计研究

针对目前我国大中口径舰炮供弹系统急待改进的现状,在借鉴国内外供弹系统现有技术的基础上,提出了一套新型大中口径舰炮敏捷供弹系统.说明了这种大中口径舰炮供弹系统的设计方案;转运间布置圆柱凸轮分度机构驱动的间歇式转动的弹鼓,直动盘形凸轮机构实现弹从弹鼓到升降机弹位转换;伸缩液压缸为动力,齿轮齿条机构增速的升降机;摆动液压缸实现的分弹器配合直动液压缸把升降机输送来的弹推送到装弹摆臂;装弹摆臂摆动到与身管平行并输弹到压弹机.给出了装填第一发弹所需的相应时间,以及连续供弹的频率.设计方案从根本上解决了大中口径舰炮供弹系统自动化和更换弹种问题.     

A new energy-absorbing bolt used for large deformation control of tunnel surrounding rock

In order to control the large deformation of tunnel surrounding rock, a new energy-absorbing bolt is developed. This bolt can be transformed into a rigid support when the deformation of the surrounding rock reaches the length of the sleeve tube, thus preventing the surrounding rock from continuing to deform. Moreover, this bolt has a simple structure and is easy to manufacture and assemble. Then the static tensile test is conducted on the bolt specimen to test its working performance. The test results show that when the cone angle of the cone block is small, the load–displacement curve of the bolt contains three stages; when the cone angle is large, the load–displacement curve contains only two stages. Meanwhile, both the average constant resistance and the maximum absorbed energy increase linearly with the increase of cone angle. On this basis, ignoring the influence of shear stress, and it is supposed that the thickness of the sleeve tube is constant, then the theoretical calculation formula of constant resistance for the new bolt is derived, and the rationality of the formula is verified using the static tensile test results. It is found that the error of the calculated result is less than 15% when the cone angle does not exceed 15°. At last, the numerical simulation method is used to analyze the performance of the new bolt. The simulation results indicate that the generation of shear stress and the change of tube thickness during the movement of the cone block are two important factors that cause theoretical errors.     

T形钢管混凝土组合柱-钢筋混凝土梁外伸端板连接节点抗震性能试验研究

为了研究T形钢管混凝土组合柱-钢筋混凝土梁外伸端板连接节点的抗震性能,按1:2的比例设计并制作了9个试件进行低周往复荷载试验。观察了试件的受力过程和破坏形态,得到了试件的滞回曲线和骨架曲线,分析了节点的荷载特征值、延性、耗能性能和刚度退化。试验结果表明：此类节点滞回曲线饱满,延性系数均大于3.48,粘滞阻尼系数均大于1.5,具有良好的抗震性能。加长牛腿长度能提高节点的初始刚度和极限荷载;增加端板厚度和设置加劲肋,节点的极限荷载和耗能性能提高,且加劲肋对薄端板的影响比厚端板显著;增大螺栓直径能提高初始刚度,但对节点承载力影响有限。     

基于有限元法的机械连接静力分析的研究

在复合材料结构设计中,连接问题比较复杂,连接强度与铺叠方式、载荷方向等因素密切相关,对于多排钉孔传力时的钉载荷分配更难以预测。笔者利用MSC．NASTRAN有限元分析软件,选取几种典型连接范例,计算了这几种连接形式下的钉载分配并给出了这几种连接下的钉载分配曲线,结果与工程算法结果相吻合。将此种连接仿真方式应用于空间遥感器连接部件的有限元模型计算中,分析结果与实验分析结果在规定误差内。     

Strength and deformation behaviors of bedded rock mass under bolt reinforcement

The mechanism of bolt support is an important topic in mining engineering and slope treatment. The artificial material and loading system were self-developed to study the influence of bedding cohesion and bolt number on the anchoring behavior of bedded rock mass. The results show that, both peak strength and elasticity modulus increase gradually with the increase of bedding cohesion and bolt number. The axial stress–strain curve of bedded rock mass under the reinforcement of bolts presents the features of strain-softening and secondary strengthening. Finally, anchoring behavior of bedded rock mass with different bolt numbers was simulated by using FLAC3 D numerical program and the results were compared with the experimental results. This study can provide certain bases to the stability control and support design of bedded rock mass in roadway.     

全长锚杆的无损检测研究

锚杆是地下工程及边坡工程施工中的一种重要手段,是一种隐蔽性的重要工程,因而对其进行质量检测是非常必要的.目前锚杆检测主要采用动测法.全长锚杆是目前应用较多的一种锚杆,对于全长锚固锚杆中锚固质量为优的锚杆来说,由于看不到底端反射,因而只能根据经验或依据能量衰减与锚固段长度呈指数关系,用测定能量衰减变化量来预测全长锚固锚杆的长度.全长锚固锚杆底反射变得很弱或消失,这是很有意义的信息,应进一步深入研究.目前锚杆的注浆饱和度测试仅处于定性或半定量的状态,不能精确定量地给出注浆饱和度值,但它对锚杆质量判断仍具有很高的实用性.更精确的定量判断还有待进一步的试验研究.     

Experimental and theoretical investigation on mechanisms performance of the rock-coal-bolt (RCB) composite system

For coal mines, rock, coal, and rock bolt are the critical constituent materials for surrounding rock in the underground engineering. The stability of the “rock-coal-bolt” (RCB) composite system is affected by the structure and fracture of the coal-rock mass. More rock bolts installed on the rock, more complex condition of the engineering stress environment will be (tensile-shear composite stress is principal). In this paper, experimental analysis and theoretical verification were performed on the RCB composite system with different angles. The results revealed that the failure of the rock-coal (RC) composite specimen was caused by tensile and shear cracks. After anchoring, the reinforcement body formed inside the composite system limits the area where the crack could occur in the specimen. Specifically, shearing damage occurred only around the bolt, and the stress-strain curve presented a better post-peak mechanical property. The mechanical mechanism of the bolt under the combined action of tension and shear stress was analyzed. Additionally, a rock-coal-bolt tensile-shear mechanical (RCBTSM) model was established. The relationship (similar to the exponential function) between the bolt tensile-shear stress and the angle was obtained. Moreover, the influences of the dilatancy angle and bolt diameter of the RCB composite system were also considered and analyzed. Most of the bolts are subjected to the tensile-shearing action in the post-peak stage. The implications of these results for engineering practice indicated that the bolts of the RCB composite system should be prevented from entering the limit shearing state early.     

[研究生论坛]预制装配式混凝土墙板螺栓连接抗剪性能试验研究

为研究预制装配式混凝土墙板螺栓连接的抗剪性能,通过对4个采用装配式螺栓连接的预制墙板结构试件进行单向反复加载试验,获得了试件的滞回曲线、骨架曲线、特征荷载与位移,在此基础上对装配式螺栓连接的刚度退化情况以及延性指标进行了计算和分析。研究结果表明：装配式螺栓连接具有良好的承载力、刚度及耗能能力,是一种可靠的干连接方式;通过对薄弱部位进行箍筋加密和增加螺栓的个数,能显著提高装配式螺栓连接的抗剪性能。     

异形内R型螺栓头部支承面压力有限元分析

提出了一种新的异形内Ｒ型螺栓构形,并采用间隙无磨擦接触问题的分析以及有限元计算方法,对其支承面上的压力分布进行了分析,进而得出了一种提高支承面压陷的极限压力以及对螺栓头部支承面进行构形优化的新途径。