重複荷重による材料の疲労度に関する一実験
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- 鵜戸口 英善
- 東京大学工学部
書誌事項
- タイトル別名
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- An Experimental Investigation on Fatigue Damage by Means of Multiple Repeated Loads
抄録
Fatigue tests with repeated loads of two steps and sequential multiple steps were made on 0.35% carbon steel specimens by means of a rotary bending fatigue tester of Ono's type. The specimens were normalized in blank before machining at the temperature of 870°C in 1 hour, with subsequent air-cooling. The mechanical properties of the material are given as follows: tensile strength σB=56.6kg/mm2, lower yield point σS=32.2kg/mm2, elongation φ=27.3% and the fatigue limit σwb=28.1kg/mm2.<br>In the test of two steps loading, four kinds of loading, namely σ1_??_σ2=30_??_37.7kg/mm2 (beyond the yield point) and 28.9_??_31.8kg/mm2 (beneath the yield point) were applied in various cycle ratios, to investigate the aspects of fatigue damage. In the test of multiple steps loading, sequentially ascending and descending loadings of equal 2, 4 and 8 steps in equal cycle ratios were applied in the same range of stresses as in the case of the two steps loading, and the variations of the endurance life were measured.<br>The test results can be briefly summarized as follows. When the sequential loading is an ascending type, the total sum of cycle ratios up to fatigue fracture is larger than unity, ascending up to 1.3 in average, while the sequential loading is a descending type, the total sum of cycle ratios is smaller than unity, descending down to 0.7 in average. The value of the sum of cycle ratios is almost independent of the number of steps in sequential loadings, whether the stress amplitudes exceed the yield point or not. While scattering of the test results was more remarkable in ascending loadings than in descending loadings. The test results were compared to those of the theoretical prediction by D. L. Henry, and the reason for the scattering of the test results in ascending loadings and some other considerations are discussed.
収録刊行物
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- 材料試験
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材料試験 6 (45), 361-367, 1957
公益社団法人 日本材料学会
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詳細情報 詳細情報について
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- CRID
- 1390282680344469632
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- NII論文ID
- 130003929264
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- ISSN
- 03727971
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- 本文言語コード
- ja
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- データソース種別
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- JaLC
- Crossref
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可