基于有限元分析的金枪鱼延绳钓钓钩力学性能研究

Mechanical properties of tuna longline hook based on finite element analysis method

掌握金枪鱼延绳钓钓钩的应力、变形等力学性能有利于改进钓钩设计和正确选用材料。实验针对生产实际中常用的2种钓钩（环形钩和圆形钩）进行三维实体建模,利用ANSYS软件对其进行有限元分析,获得钓钩的等效应力、变形的分布模式和可能的破坏条件及形式;由同尺寸和同结构钓钩的拉伸实验结果验证了数值分析得到的最大应力和变形结果,并根据数值分析的结果对钓钩进行了结构优化分析。结果显示：（1）同规格环形钩的抗拉强度优于圆形钩15.80%-29.40%,环形钩X、Y轴最大变形率比圆形钩分别小3.00%和0.21%;（2）钓钩的主要受力区域在后弯处（承受83.00%-86.00%的应力）,轴头孔下端存在应力集中;（3）对后弯、前弯表面进行压扁处理（压下率为15.00%）,适当增加钓钩后弯的圆弧曲率（曲率半径由14 mm增至16 mm）、钩轴采用圆弧过渡等措施,可提升钓钩强度4.60%-10.80%。研究表明,圆形钩是良好的生态保护型钓钩,强度满足使用要求,可在延绳钓渔业中使用。

The stress,strain and deformation after the hook in the stress play a decisive role on the mechanical properties and structural stability of the hook. The pros and cons of the mechanical properties of the hook directly affect the capture effectiveness of the target species. It is beneficial to improving the hook design and material selection to understand the mechanical properties（ eg. tension and deformation） of tuna longline hook. There are some advantages for the circle hooks,such as reducing the sea turtle by catch rate,high survival rate after capture release,lowescaping rate,etc.. There is a trend that circle hook replaces the ring hook and J hook. The deformation or fracture of hook will make longline fishing invalid. Therefore,the hook should have enough stiffness and strength when the hook is designed and the material is determined.Mechanical analyses are carried out on two kinds of typical hooks（ ring hook and circle hook） using finite element analysis method（ FEM） by ANSYS. The distribution of equivalent stress,strain and deformation of hook are obtained,and the possible failure condition and the failure type are also analyzed. Intensity examination and optimization design are made on hookstructure based on material mechanics theory,compare with hook＇s data obtained in the tensile test. Results showed：（ 1） With the same specifications,ring hook＇stensile strength is higher than that of circle hook by 15. 80%-29. 40%,and the max. deformation rate in X and Y axis of ring hook is smaller than that of circle hook by 3. 00% and 0. 21% respectively;（ 2） Hook＇s main stress is undertaken by the bend of the hook（ 83. 00%-86. 00%）,and there is a stress concentration in the hole of hook eye;（ 3） Flattening the bends surface（ flattening rate is 15%）,increasing the hook circular arc of the bending curvature appropriately（ the radius increased from 14 mm to 16 mm）,connection of hook eye and shank added with arc transition can avoid stress concentration and enhance the strength of the hook by 4. 60%-10. 80%. This study suggests that（ 1） Circle hook is the eco-friendly hook type;（ 2）Its tensile strength meets the requirement of the fishing; and（ 3） It can be used in the longlining.