高度復元ばね特性の非線形解析 (釣竿の大たわみ変形)

In recent years, leisure activities, such as tennis, golf, skiing, fishing, etc. are very popular. The performance of various instruments used in such leisure activities is also greatly improved. Scientific analysis on the function of such instruments is essential in order to develop practical instruments in the field of sports-leisure. Various experiential studies that clarify the characteristics of fishing rods have been published. However, there are very few scientific studies about fishing rods in the field of the so-called sports-leisure. This study deals with large deformation of fishing rods that would be useful in the development of the characteristic design of fishing rods. In this report, based on the nonlinear large deformation theory, new fundamental equations are introduced for thin, straight tapered fishing rods with a circular cross-section under concentrated loads at the free end. As a result, it is found that the large deformations of fishing rods can be described by nondimensional load parameters, the ratio of rod diameter at end and bottom, and supporting angles. Furthermore, the experimental verification of this analysis is carried out using a flexible rod acquired in the market. The theoretically predicted results are in fairly good agreement with the experimental data. Consequently, the new deformation theory is proved to be of practical use.