不规则波下起重船吊索动张力特性分析  

Sling dynamic tension analysis of a crane ship under irregular wave

作　　者：杨晓蓉[1,2] 周永波 王艳红[1] YANG Xiao-rong;ZHOU Yong-bo;WANG Yan-hong(Dept.of Basic Courses,Military Transportation Univ.,Tianjin 300161,China;Renai College,Tianjin Univ.,Tianjin 301636,China)

机构地区：[1]军事交通学院基础部,天津300161 [2]天津大学仁爱学院,天津301636

出　　处：《海军工程大学学报》2018年第4期87-94,共8页Journal of Naval University of Engineering

摘　　要：为了提高海上过驳作业的安全性,分析起重船和吊物的运动对吊索动张力的影响,首先用三自由度的锥摆模型描述吊物的运动,并根据拉格朗日方程建立了吊物系统的动力学方程以及吊索动张力计算公式;然后,依据Pierson-Moskowitz谱表示不规则波面升高,得到不规则波波面升高时间历程作为船体运动的外激励,计算了时域内船体六自由度的运动响应;随后,将船体六自由度运动响应作为激励计算吊物的运动响应以及吊索的动张力;最后,以一条起吊重量为1 300t的起重船为例进行数值仿真,分析了三种工况条件下吊物的运动响应和吊索的动张力,包括时域分析和谱分析。分析结果表明:波高对吊索动张力的影响较大,当波高达到1m时,斜浪下(45°)吊索动张力是波高0.1m时吊索动张力的14倍;在共振区域吊索动张力急剧增加,在波高为1m时,斜浪下(45°)共振区间的吊索动张力是非共振区间吊索动张力的近33倍;匀速起吊或下降吊物,并不会额外增加吊索动张力;在非共振区吊索动张力响应的频率范围跨度较大,而在共振区,响应频率范围相对较小,能量更加集中,峰值特性明显。In order to improve security of lightering at sea,the influence on the dynamic tension of the sling is analyzed,which is made by the motions of a crane ship and the lifted cargo.Firstly,the motion of the lifted cargo in the body-fixed coordinate system O′-x′y′z′is described with a three-degree-of-freedom conical pendulum model.The motion equation of the lifted cargo and the calculation formula of the sling dynamic tension are derived from Lagrange′s equation.Secondly,the irregular wave surface elevation is expressed on the basis of the Pierson-Moskowitz wave spectrum.The six degree-of-freedom motion responses of the crane ship are gotten when the irregular wave surface elevation is considered as excitations.Lastly,the six degree-of-freedom motion responses of the crane ship are considered as excitations in order to obtain motion responses of the lifted cargo and the sling dynamic tension.The sample crane ship has a lifting capacity of 1 300 t.The motions of the lifted cargo and the sling dynamic tension are calculated with time domain and spectrum analysis methods.The results show that the wave height has a noticeable impact on the sling dynamic tension.In oblique wave(45°),when the wave height is 1 m,the sling dynamic tension is fourteen times more than that under the wave height being 0.1 m.The sling dynamic tension rapidly increases in resonance area.In oblique wave(45°),when the wave height is 1 m,the sling dynamic tension in resonance area is 33 times more than that in non-resonance area.The sling dynamic tension does not increase and the maximum resonant responses of the lifted cargo are less than that in constant sling length when the lifted cargo is in lifting and lowering at constant speed.Spectrum analysis shows that frequency domain of the sling dynamic tension in non-resonance area is wider.However,in resonance area,the frequency domain of the sling dynamic tension is narrower,the energy is more concentrated and the peak value character is more notable.

关 键 词：海上过驳 起重船 吊物系统 吊索动张力 不规则波 时域分析 谱分析 

分 类 号：U692[交通运输工程—港口、海岸及近海工程]