Calculation And Design Method Of Fishing Rod Bengding Curve Based On Large Deflection Theory

With the ever-increasing living standards of the people in China,leisure fishing based on traditional fisheries and recreation has become an emerging industry developed to meet the material and cultural consumption demands.Fishing rod is an indispensable tool for fishing,and its performance affects the play of fishing technology and consumer experience.However,due to the fact that research on the design theory of fishing rods in China is seriously lagging behind,there is no perfect fishing rod structural design theory and related standards up to now,which seriously restricted the design,production and development of high-end fishing rods.The establishment of a quantitative calculation theory for the mechanical performance of fishing rods and the development of structural design methods based on quantitative calculation theory are of great significance to the healthy and sustainable development of the fishing rod industry.The bending curve of the fishing rod is an important index of mechanical performance reflecting the characteristics of fishing rod.The maximum horizontal displacement of fishing rod could reach 20.8 cm when bending is calculated by the large deflection theory,and the reason for the error of small deflection theory is that the horizontal displacement is neglected.Based on the large deflection theory,this paper deduces the bending curve equation of fishing rod made by carbon fiber reinforced epoxy resin.And through experiments,the rationality of the calculation theory was verified.Firstly,the theory of calculating the bending curve of the fishing rod was verified by single-section fishing rods with single thickness,and the experimental results for the single fishing rod showed that the absolute error between the theoretical value and the measured value of each position was no more than 2cm.,and Relative error no more than 5%.Based on the assumption of double-fishing rod solid connection,the rationality of the nested hypothesis was verified by comparing theoretical bending curves of the double-section fishing rod of the same thickness with experimental bending curves.Due to the multiple taper of the mould during the preparation of the fishing rod,carbon fiber often appears non-integral layer after winding.The substitution method was used to convert the non-integral layer into a percentage of the whole thickness according to the actual layer length,and the variable thickness composite material fishing rod was prepared by a variable taper mould to verify the rationality of the substitution method.Finally,through theoretical calculation and experimental analysis of double-section fishing rod with variable thickness,it is revealed that the nested,variable section and variable taper mould have a comprehensive effect on the calculation results.The results show that the maximum error is 0.83 cm.It can be seen that the fishing rod bending curve calculation theory and its influencing factors in this topic can reflect the characteristics of the actual bending curve of the fishing rod and can be used as a theoretical basis for the design of the fishing rod bending curve.Based on the theoretical basis of the fishing rod bending curve calculation,the design process of the fishing rod bending curve was formulated,and the fishing rod bending curve design software was compiled.The software uses the reference bending curve of the fishing rod as the design objective function.By designing the section size,material,and carbon fiber pavement,the bending curve of the fishing rod meeting the error index requirements is designed.Two typical fishing rods(single and double rod)were designed and manufactured using fishing rod bending curve design software.By comparing the measured bending curve of the design of the fishing rod with the reference bending curve,we can see that the absolute error of the designed single-fishing rod measured curve and the reference bending curve is 1.5cm.The designed two-section fishing rod is actually measured,the maximum absolute error between the measured bending curve and the reference bending curve is 0.5 cm,which satisfies the error index requirement.The front end limit load of single rod and double rods were 2.94 N and 5.71 N,and the Structural limit load of single rod and double rods were 31.36 N and 58.8 N,all meeting the requirements for use.In summary,the results of calculation and experimental analysis show that the calculation theory and design method used in this paper are reasonable and can be used to guide the structural design of the fishing rod.