仿粒突箱鲀的起重机箱梁风荷载减载设计方法

Bionic Design Method for Crane Box Girder Wind Load Reduction Based on Ostracion-Cubicus

风荷载是起重机大车运行时的重要载荷,主梁作为起重机的主要挡风构件,针对主梁的减载设计可以有效地降低起重机运行能耗,本文以粒突箱鲀的结构为启发,探究起重机箱梁风荷载的仿生减载设计方法.首先运用灰度转换、二值图像转换及边缘检测方法提取箱鲀鱼嘴特征廓线,获得以箱梁特征高度为设计变量的仿生设计模型,然后通过箱梁迎风面附着轻质材料的方式实现传统起重机箱梁的仿生设计,并运用计算流体力学软件(FLUENT)对仿生设计进行评估.研究结果表明:以某40 t集装箱起重机箱梁为例,采用聚苯乙烯泡沫作为轻质贴附材料的仿生箱梁较传统箱梁结构风阻减小65.77%,而仿生贴附结构仅使箱梁增重2.28%;仿生箱梁的流线外型减轻了由迎风面处边界层分离带来的流场扰动,降低了结构的气动力脉动值,提高了起重机在风场中运行的平稳性.

The wind load is an important load during the gantry crane operation,and the crane box girder is the major windshield component.Therefore the wind load reduction design for the crane box girder can decrease the crane energy consumption effectively.The bionic design method for the crane box girder wind load reduction based on the geometry of ostracion-cubicus was explored.Firstly,the ostracion-cubicus mouth feature profile was extracted through gray level conversion,binary image conversion and edge detection method.On this basis,a bionic model was built with the box girder height as the design variable.Secondly,the bionic design of the traditional crane box girder was realized by attaching the light material to the windward side of the box girder.Finally,aerodynamic characteristics of the bionic box girder was evaluated with FLUENT.A 40 t container crane was taken as an evaluation case,and comparison was made between the original and the bionic ones,expanded polystyrene(EPS)was selected as the attachment material.The research shows that the wind load decreases by 65.77%with the bionic girder,while the weigh is only 2.28%more than the original one.The flow field disturbance from the boundary layer separation reduces due to the streamlined structure of the bionic girder,which decreases the lift pulsation,improves the running stability of the crane in the wind field.