Research On High Strength Connection Design Of Marine Towing Cable Ending-fitting

Towed cable is the key equipment of towed detection instrument in the development of Marine resources,and its ending-fitting is an important part to realize the connection between the cable body and the upper floating body equipment,mainly bearing axial load.As the development of Marine resources is oriented to deep water,the connection performance of the joint becomes the key bottleneck of the application of towed cable in deep water.The conceptual form of towed cable ending-fitting in China adopts adhesive type,which mainly faces the key problems of various adhesive materials,lack of perfect theoretical guidance in structural design and lack of standardized manufacturing process,so that it cannot meet the high strength connection standard.Therefore,this paper studies from four aspects of material selection,structural design,process defects and experimental verification to provide reference for the localization of high-strength joint.The main research contents are as follows:(1)Research on selection of epoxy resin adhesive material.A material selection method based on TOPSIS analysis technology was proposed.According to the mechanical characteristics of the bonded joint,the tensile strength,shear strength and anchoring strength were determined as the key performance indexes.The tensile test,shear test and anchoring test were carried out for four commonly used epoxy resin adhesives,and the properties of the four epoxy resin adhesives were evaluated according to the relative weight of the test results in the ending-fitting anchoring system.(2)Research on structural design of adhesive ending-fitting.Three bonding theoretical models were analyzed to determine the calculation method of the connection force.Based on the two-line cohesive force model,the finite element analysis of debonding failure was carried out to simulate the damage and failure process of the bonding interface during the axial loading process,and the prediction of the axial bearing capacity was realized.The influence of structural parameters of armored steel wire inside the bonding ending-fitting on the axial bearing capacity is further analyzed,and the value range of structural parameters is discussed based on the numerical analysis results.(3)Research on the influence of processing defects on the ending-fitting performance of adhesive ending-fitting.Numerical simulation models of single steel wire bonding and multiple steel wire bonding were established to analyze the influence of different defect types(size,location,quantity)on structural failure forms and axial bearing capacity.Based on the above conclusions and the process of adhesive,three methods of eliminating large size defects are proposed.(4)Experimental verification of ending-fitting performance before and after completing the design.A method was proposed to evaluate the ending-fitting performance by the percentage of the axial bearing capacity of the ending-fitting to the ultimate tensile force of the cable body.