| 号数 | ばね論文集 64 号（ 2019 年） |
| ページ数 | pp.79-87 |
| 種類 | 論文 |
| 論文名 | 圧縮及び引張コイルばね中の表面き裂の応力拡大係数のFEM 解析 |
| Title | FEM Analyses of Stress Intensity Factors for Surface Cracks in Compression and Tension Coil Springs |
| 著者 | 中曽根祐司1)，村主和憲2)，川上 奏3) |
| Author | Yuji NAKASONE1), Kazunori MURANUSHI2),Kanata KAWAKAMI3) |
| 抄録 | 本研究では，圧縮コイルばねのコイル内側素線表面上の半楕円表面き裂の3次元FEM解析を実施し，3種類のモードの応力拡大係数の修正係数Fi (i=I, II, and III)に及ぼすばねのパラメータの影響を調べた．本研究では，素線の赤道線とき裂のなす角度，すなわちき裂傾斜角及びき裂のアスペクト比a/cの2種類のばねのパラメータの影響を調べた．ここで，aはき裂深さ及びcはき裂表面長の半分である．解析結果は以前発表した著者らの引張コイルばねの結果と比較検討した．き裂傾斜角に対しては，圧縮コイルばねではFII，引張コイルばねではFIが支配的になった．アスペクト比a/cに対しては，圧縮及び引張コイルばねともにFIが支配的となり，FIa/c関係は離心角に対して同様な変化を示した．すなわち，≒0°, 180°の素線表面では，FIa/c関係はa/cに対して上に凸の2次曲線で表され，a/c= 2.0で最大値をとったが，=45°, 90°, 135°ではa/cの値とともに単調に減少した． |
| Abstract | In this study, 3D finite element analyses have been made on the stress intensity factors for semi-elliptic surface cracks on the inner wire surface of compression coil springs in order to investigate the effects of spring parameters on the correction factors Fi (i=I, II, and III) for the three modes of the stress intensity factors. The parameters selected for the present analyses are crack inclination angle, or the inclination angle of the cracks to the equator of the wire,θand crack aspect ratio a/c where a is crack depth and c half crack surface length. The results are compared and discussed with those obtained by the present authors’ previous work for tension coil springs. For crack inclination angleθ, FII was dominant over the other two factors in compression coil springs whereas FI in tension coil springs. For crack aspect ratio a/c, FI was dominant and the FI−a/c relationships showed a similar tendency for eccentric angleφin the both types of coil springs. Namely, the relationships were represented by quadratic curves of a/c projected upward and the FI value reached its maxima for a/c=2.0 near wire surface at φ≒0° and 180°. The FI values, however, were monotonically decreased for increasing a/c value at φ=45°, 90° and 135°. |
| 著者の所属 | 1)東京理科大学 2)元東京理科大学大学院生 3)東京理科大学学生 |
| Belonging | 1)Tokyo University of Science 2)Former Graduate Student, Graduate School, Tokyo University of Science 3) Student, Department of Mechanical Engineering, Tokyo University of Science |
| Key Words | Compression, Tension, Coil Spring, Surface Crack, Stress Intensity Factor, Mixed Mode,FEM |