Force performance of trawl system – III: mathematical modeling (part I)

The force performance of trawl systems directly depends on the work performed by these forces.The mechanical work of a trawl system is a physical quantity that depends on the vectors of force (hydrodynamic, tension, compression, etc.) and displacement. Thermodynamic work is the amount of energy transmitted or received by the trawl system by changing its external parameters. There is also the work of the forces of the electrostatic field when the charge moves from one point of the field to another. Equations are obtained for ideal flexible steel ropes and rope-rope products, characterizing the direct proportionality of the ratio of the productivity of forces that are directed perpendicular to each other and depend on the Poisson's ratio and the constructive elongation of ideal flexible steel ropes and cordage products. The ratio of the capacities of the forces or the ratio of the moduli of elasticity in the transverse and longitudinal directions, which arise when steel ropes and rope-rope products are stretched, are inversely proportional to the square of the coefficient k connecting the elongation λ, Poisson's ratio μ and the relative elongation ε at a constant volume of the product and its mass. There has been described an example of stretching perfectly flexible steel ropes and cordage. Such constructive parameters as lay, the number of strands, wire and fiber thickness, type of weaving were not taken into account.