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一种基于有限元原理的非线性混合法被用于预测捕捞作业中的金枪鱼延绳钓的形状与张力,为渔具设计提供理论方法,并以期在设计阶段能替代传统的水槽模型试验,为实际渔业生产作业调整提供有益的技术参数。构成延绳钓渔具的绳索可以被一系列绝对柔软的被称为绳索要素的单元所模拟,因此,整个延绳钓渔具可以被看作为一系列绳索要素在其两端点通过无摩擦铰接连接而成的集合体。根据最小位能原理,可以导出描述系统平衡状态的非线性基本平衡方程式。利用Newton-Raphson方法,通过一系列的负荷-形状迭代法求解基本平衡方程式,可以获得海流作用下延绳钓渔具作业时的形状和张力分布的数值解。简化模型的回流水槽试验验证表明,本方法具有较好的计算精度和解的收束性与稳定性。
A nonlinear hybrid method based on the finite element principle is used to predict the shape and tension of tuna longline fishing in fishing operations and provides a theoretical approach to the design of fishing gear. It is expected that during the design phase, the traditional tank model test will be replaced. Fishery production operations to adjust to provide useful technical parameters. The ropes that make up the longline gear can be modeled by a series of absolutely soft elements called ropes elements so that the overall longline gear can be seen as a series of rope elements joined at both ends by frictionless articulation The collection. Based on the principle of minimum potential energy, a nonlinear basic equilibrium equation describing the equilibrium of the system can be derived. By using the Newton-Raphson method, a series of load-shape iterative methods can be used to solve the basic equilibrium equation to obtain the numerical solution of the shape and tension distribution of longline fishing gears under sea current operation. Experimental results show that this method has good calculation accuracy and convergence and stability.