大型全回转浮式起重机平衡系统优化数学模型

针对大型全回转浮式起重机的结构和工况特点,在满足抗倾覆稳定性要求下,将浮式起重机自重产生的不平衡力矩与起升货物产生的不平衡力矩之和的均方根力矩作为目标函数值,建立以平衡系统主要构件强度、刚度、结构尺寸和回转轮压合理性为约束条件的多目标设计优化数学模型,运用遗传算法优化浮式起重机平衡系统,最终得出优化数据.该数学模型在具体优化过程中取得较为满意的优化结果,为大型全回转浮式起重机的设计优化提供有效方法.  

Nonlinear Dynamics in the Motion of Floating Cranes

The nonlinear dynamics of a floating crane is investigated. The motion of the system – consisting of the hull with the crane, the load and a nonlinear mooring system – was found to exhibit various nonlinear phenomena. Operating conditions, in which the motion of the vessel or the load is highly dependent on the initial conditions or disturbances are of special interest. Bifurcations in which a small change of a parameter value causes a large qualitative change of the dynamics often limit the range of save operation.For a floating crane which is periodically forced by waves, different mathematical tools are used to investigate resonances and subharmonic motions. The multiple-scales method allows for the analysis in frequency domain and path following algorithms are applied for a numerical bifurcation analysis. The results of both methods agree very well with each other and both offer tools that could help for the evaluation of operating conditions of crane vessels.  

大型浮吊滑动摩擦材料回转支撑力学行为

针对浮吊的轻量化设计,采用非金属滑动摩擦材料Nylatron 703XL取代以往的滚动式回转支撑.对Nylatron 703XL材料试样进行压缩试验,获得材料的压缩性能曲线,发现这种材料的压缩性能曲线呈现明显的非线性特征,对结构分析的影响显著.针对2×8 000 t大型浮吊,用Abaqus计算得到不同工况对Nylatron 703XL垫圈的力学响应和规律.计算分析摩擦因数对垫圈力学行为的影响.结果认为:Nylatron 703XL具有取代金属结构的能力,可以作为滑动摩擦材料;其在工程机械承载结构上应用的潜力巨大.  

7500吨浮吊齿轮箱故障诊断系统的研究

针对7500吨浮吊齿轮箱故障诊断问题,将离散小波变换和Tikhonov支持向量机结合建立了一个浮吊齿轮箱故障诊断系统。在输入层对振动信号进行离散小波变换,提取不同频带的能量参数作为故障特征向量,利用这些特征向量进行Tikhonov支持向量机的学习,训练后的Tikhonov支持向量机诊断浮吊齿轮箱故障。实验结果表明,离散小波Tikhonov支持向量机具有很强的故障识别性能和鲁棒性,诊断精度优于常规的BP网络方法。