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.

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。

结合宁高新通道二期工程石臼湖大桥工程栈桥施工经验,根据确定的长大应急通道总体方案,提出采用起重机架设法架设该通道时的总体施工方案和施工流程.首先阐述架设作业准备工作,然后分别给出上部结构和下部结构施工方案,并针对水上施工点的设置进行简要说明,最后分析通道架设和长期使用过程中,可能存在的影响桩稳定性及桩承受重大荷载后产生沉降而影响通道结构正常使用的问题,通过设置伸缩缝、制动墩或双排桩,加设型钢等垫块或辅助支撑桩,分别予以解决.

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.