活塞蓄能器式管路阻尼器的理论与试验研究(英文)

It can be beneficial to reduce vibrations in shipboard piping, so the authors designed a new kind of piping damper with a plunger-type accumulator. Special requirements for the piping damper included low impact displacement, low speed, as well as an appropriate locking speed. Inside the damper, a plunger-type accumulator was installed and on the outside of the piston rod, a tube with exposed corrugations was added. Between the piston and the cylinder, a clearance seal was added. Using mathematical modeling, the effects of the dynamic performance of the damper’s impact displacement on vibrations were observed. Changes to the clearance between the piston and the cylinder, the stiffness of the spring in the accumulator, the throttle valve size, and locking speed resistance of the damper were respectively simulated and studied. Based on the results of the simulation, dampers with optimal parameters were developed and tested with different accumulator spring stiffnesses and different throttles. The simulation and experimental results showed that parameters such as seal clearance between piston and cylinder, accumulator spring stiffness and throttle parameters have significant effects on the damper’s impact displacement, low speed resistance and locking speed.     

船舶在规则纵浪中的混沌运动

Parametric resonance can lead to dangerously large rolling motions, endangering the ship, cargo and crew. The QR-factorization method for calculating (LCEs) Lyapunov Characteristic Exponents was introduced; parametric resonance stability of ships in longitudinal waves was then analyzed using LCEs. Then the safe and unsafe regions of target ships were then identified. The results showed that this method can be used to analyze ship stability and to accurately identify safe and unsafe operating conditions for a ship in longitudinal waves.     

穿浪双体船横向强度与扭转强度的有限元计算

穿浪双体船的连接桥在横浪和斜浪中遭受比较大的横向弯矩和扭转力矩的作用,其自身的强度对穿浪双体船的安全性来说至关重要。本文在有限元理论的基础上,采用直接计算方法对一艘穿浪双体船进行了横向强度和扭转强度的整船有限元分析,对其总强度进行了校核,并初步分析了该船上层建筑对总横强度的影响。通过对计算结果的分析,掌握了该船的应力分布,为结构优化设计提供依据。     

双体船连接桥结构强度的简化计算

双体船的连接桥结构强度是设计时需要重点考虑的问题,采用全船有限元法来分析计算要耗费大量的时间。将连接桥结构简化为一种梁模型,采用简化解析计算方法来分析其扭转强度和横向强度,并与实船的全船有限元法的对比分析结果表明：简化模型和计算方法是可行的,可应用于双体船初步设计阶段,估算连接桥的结构强度,指导结构设计。     

预应力钢筋混凝土岔枕的受力分析

就应预应力钢筋混凝土岔枕的受力状况进行理论分析,并对不同道床系数时的岔枕进行了受力计算,为预应力钢筋混凝土岔枕在列车提速、大型岛固机作业提供强度理论依据。     

基于FBG表面应变仪的隧道监测系统

由于隧道使用期较长、环境恶劣,因此及时对隧道结构性能进行检测和诊断、对可能出现的灾害进行预测并评估其安全性已经成为隧道工程的必然要求.为此,在分析FBG传感器传感原理的基础上,将FBG表面应变仅用于隧道表面应变监测;同时在现场进行了FBG传感器与钢弦式传感器的对比试验.试验结果表明:FBG传感器具有很高的测试精度,长期稳定性好,信号传输距离远,是隧道长期监测的一种可靠而有效的手段.     

人工智能在汽车自动驾驶中的应用

我国已经正式迈入了科技社会,各种科学技术在飞速发展,其中最引人注目的 就是人工智能技术,人工智能技术的应用范围非常广,包含生活、交通、建设等各个方面.随着研究的深入,人们现在已经将人工智能技术融入到汽车驾驶中,形成了新的汽车自动驾驶技术.这种自我控制的技术在一定程度上可以减少事故发生的概率,这种技术完全颠覆了传统的汽车...     

Equality of bargaining power in contracts for international liner shipping

Mandatory rules exist in contracts for international liner shipping primarily because of imbalances and non-equity in the allocation of contract responsibilities. The superior bargaining position owned by the carriers depends largely upon liner market monopoly levels, the supply and demand balance between the shipper and carrier, and the cargo volume size of the shippers. With the development of shipping technologies, mode of transport, and shipping competition policy, the unequal comparison of bargaining forces between shippers and carriers changes. When the existing mandatory rule was deemed no longer necessary due to changing circumstances, legislation requirements to restore freedom to contract became apparent. When both sides have equal bargaining power, adoption of the principle of freedom of contract for their business relationships is suitable. The Rotterdam Rules concerning freedom of volume contract construction is based on equal bargaining powers between both sides and responds to the evolving situation of the industry. The Rules represent the development trend of today’s theory of contracts for international liner shipping and the demand for legal and institutional changes.     

椭圆余弦波对圆弧型固立防波堤的绕射波浪力

基于椭圆余弦波绕射理论,应用特征函数展开法,推导浅水波对圆弧型固立防波堤绕射的波势解,据此计算作用于防波堤的水平波浪载荷。结果表明:浅水波入射角与非线性影响参数、海况条件以及防波堤几何条件等因素的相对变化对波浪作用均存在一定的影响。与微幅波理论对比可知:在一定浅水条件下采用椭圆余弦波一阶分量模型所计算的最大无量纲波浪力均明显高于微幅波理论的对应估值,反映了水波非线性因素的影响效应。     

万吨级溢油回收船电力系统方案设计和仿真研究

溢油回收船是应对海上溢油污染事故的专用船舶。近年来随着海上石油运输愈发频繁和潜在溢油隐患提高,溢油回收船成为人们关注和研究的热点。本文针对万吨级溢油回收船电力系统的方案设计,分别论证中、低压和直流三种方案,建议采用低压交流电力系统并建立仿真模型验证方案可行性。