民用飞机超细干粉灭火系统喷射试验研究

NaHCO3超细干粉灭火剂具有环保高效的优点,有可能替代现有民用飞机上常见的哈龙1301 灭火剂,应用于未来民用飞机固定式灭火系统上。以某型民用飞机发动机灭火系统为基础,搭建了NaHCO3 超细干粉灭火系统试验台,开展了该灭火系统的喷射性能试验研究。试验结果表明灭火系统平均流量较大,性能较好,但仍需要修改管网设计调整灭火剂在风扇舱和核心舱的分配比例。初步的灭火剂浓度分析也表明目前的管网设计可以达到舱内的灭火剂浓度要求。     

具有非线性摩擦阻尼随机失谐的叶盘系统响应特性

针对目前含非线性摩擦阻尼失谐叶盘系统振动局部化机理研究存在的诸多困难,尤其是其非线性力学模型的建立和求解等难题.建立了具有滞迟干摩擦阻尼随机失谐的叶盘系统力学模型,并利用增量谐波平衡法分析了叶盘系统干摩擦力失谐度、耦合强度、黏性阻尼比和摩擦力强度等系统参数对叶盘系统受迫响应的影响规律.研究表明:含非线性摩擦阻尼的谐调叶...     

Linear Shaped Charge Cutting Property and Charge Cutting Mechanism of Mg-Gd-Y-Zn Alloy

The linear shaped charge cutting technology is an effective technology for aircraft separation. It can separate invalid components from aircrafts timely to achieve light-weight. Magnesium alloy is the lightest metal material, and can be used to cast effective light-weight components of an aircraft construction. However, the application study of the linear shaped charge cutting technology on magnesium alloy components is basically blank. In response to the demand for the linear separation of magnesium alloys, the Mg-12Gd-0.5Y-0.4Zn alloy is selected to carry out the target shaped charge cutting test. The effects of the shaped charge line density, cutting thickness, and mechanical properties on the cutting performance of the alloy are studied. The shaped charge cutting mechanism is analyzed through the notch structure. The results show that the linear shaped charge cutting performance is significantly affected by the penetration and the collapse. The higher the linear density is, the stronger the ability of the linear shaped charge cutter is, and the greater the penetration depth is, which is advantageous. However, the target structure will be damaged when it is too large (e.g., 4.5 g?m-1). Within 12 mm, when the cutting thickness of the target increases, the penetration depth increases. The lower the tensile strength is, the greater the penetration depth is, and the more conducive the penetration depth to the shaped charge cutting is. When the elongation (EL) increases to 12%, the collapse of the target is incomplete and the target cannot be separated. When the tensile strength of the Mg-Gd-Y-Zn alloy is less than 350 MPa, the EL is less than 6.5%, the cutting thickness is less than 12 mm, and the linear shaped charge cutting of the magnesium alloy can be achieved stably.     

横风下空冷塔单塔与双塔流场特性及相关改进方案的实验比较研究

本文通过对模型实验手段，比较研究了横风下空冷塔单塔与双塔的空气流场特征，较为系统地揭示了横风对空冷塔及空气动力场的主要影响原因，在基础上，比较研究了多种乘法有效的改善单双塔流场的措施，并提出了相应的工程实施建议。     

轻便摩托车降低燃油消耗量的试验研究

本文以理论分析和各项试验结果为依据，对以小型二冲程汽油机为动力的轻便摩托车降低燃油消耗量的问题进行分析、研究。通过对某些部件的改进，达到了节油的目的。将上述改进措施应用于摩托车的批量生产之中，产生了明显的经济效益和社会效益。     

循环加工编程技巧

介绍了几种循环车削加工工艺如锥体、球体等数控编程技巧。     

非线性规划的内割平面法

本文提出了一种非线性凸规划的内割平面法(ICPM),同时说明了与Kelley外割平面法交互使用的方法。并就ICPM算法给出了一个示例。     

高速铣削高强度钢时切削力影响因素析因与偏回归研究

研究了一定范围内高速端面铣削某新型高强度钢材料(>HRC42,抗拉强度σb>1.2GPa)过程中切削力的变化规律,并从切削变形机理上进行讨论与分析。通过L8(23)析因分析与偏回归分析,考察切削用量对铣削力的交互影响规律,使用残差分析与最小二乘法等统计方法,建立切削力与切削用量经验公式。     

切削颤振在线监测的试验研究

 切削颤振发生过程最显著的频域特征是包含颤振频率的某个窄频段内振动能量的急剧上升。本文根据频段能量原理提出了一种可靠的判据,并利用微型计算机实现了切削颤振的在线监测。该方法具有快速、灵敏、准确和抗干扰能力强等优点。本文还探讨了实际应用中的某些具体措施。     

激光二维切割工艺的优化

主要阐述了如何选取合适的激光二维切割加工工艺参数，如：激光器工作气体、激光器功率大小、光斑模式情况、辅助气体、激光焦点离工件的距离、加工板材性质及厚度、二维CAD／CAM控制系统等，以便达到最佳的切割质量及最少的气体消耗。