Study On Mechanical Characteristics And Fatigue Test Scheme Of The Welded Cable Clamp

For suspension bridges,the cable clamp is the key component connecting the main cable and the sling.At present,the cable clamp usually adopts casting structure,which has many defects such as complex manufacturing process,many casting defects,low material strength,poor adaptability to low temperature environment,serious environmental pollution,and long casting production cycle.Therefore,in view of the above-mentioned deficiencies of the casting cable clamp,it is especially necessary to develop a kind of welded cable clamp which is easy to form with large bearing capacity and strong reliability,meeting the requirements of low temperature environment.At present,there is a lack of research on the reasonable structural form and fatigue performance of the welded cable clamp at home and abroad.In view of the above problems,this paper conducts an in-depth study on the structural form,mechanical characteristics and fatigue test scheme of the welded cable clamp based on the Xintian Yangtze river bridge.The main research contents of this paper are as follows:1.The BNLAS model of Xintian Yangtze River Bridge is established to calculate the sling force under various load combinations and the internal force amplitude of the sling under fatigue load.Comprehensively considering the situation of the ultimate limit sling force,the internal force amplitude of the sling and the influence of the high-strength screw preload,the cable clamp corresponding to No.5 sling is determined as the research object of this paper.2.Two types of welded cable clamps are proposed,and the mechanical properties of the two types of welded cable clamps under the action of the ultimate sling force and transverse force are compared by establishing the finite element model.Comprehensively considering the difficulty of manufacturing,the advantages and disadvantages of welded cable clamp scheme I and Ⅱ are analyzed in detail,and the final structure scheme of welded cable clamp is determined.3.By setting stress extraction points,the stress distribution of the main plates and welds of the welded cable clamp under ultimate load is analyzed.The stress amplitude of the welds of the welded cable clamp under fatigue load is calculated.The fatigue strength of the welded cable clamp is checked according to the relevant specifications.4.According to the principles of fatigue test design,three fatigue test schemes for the welded cable clamp are proposed.Comprehensively considering the test precision and test cost,the fatigue test scheme Ⅲ is the focus of this paper.The fatigue test scheme Ⅲ of the welded cable clamp is analyzed,and compared with the calculation results of the actual cable clamp model.The stress equivalence of the main plates and welds between the fatigue test cable clamp model and the actual cable clamp model are analyzed.