<th id="5nh9l"></th><strike id="5nh9l"></strike><th id="5nh9l"><noframes id="5nh9l"><th id="5nh9l"></th><strike id="5nh9l"></strike>
<progress id="5nh9l"><noframes id="5nh9l"><th id="5nh9l"><noframes id="5nh9l">
<th id="5nh9l"></th> <strike id="5nh9l"><noframes id="5nh9l"><span id="5nh9l"></span>
<progress id="5nh9l"><noframes id="5nh9l"><span id="5nh9l"><noframes id="5nh9l"><span id="5nh9l"></span><strike id="5nh9l"><noframes id="5nh9l"><strike id="5nh9l"></strike>
<span id="5nh9l"><noframes id="5nh9l">
<span id="5nh9l"><noframes id="5nh9l">
<span id="5nh9l"></span><span id="5nh9l"><video id="5nh9l"></video></span>
<th id="5nh9l"><noframes id="5nh9l"><th id="5nh9l"></th>
<progress id="5nh9l"><noframes id="5nh9l">

飛機機翼緣條緊固孔細節原始疲勞質量評估方法

Evaluation method of initial fatigue quality of aircraft wing flange fastener holes

  • 摘要: 為了對飛機機翼緣條緊固孔細節原始疲勞質量進行評估,本文首先對飛機機翼緣條結構中常用的BXXX鋁合金緊固孔試件分別開展了高、中、低3種應力水平下的疲勞試驗,通過斷口判讀和反推得到3組關于裂紋長度a和疲勞壽命t的(a?t)數據,在此基礎上應用當量初始缺陷尺寸(EIFS)控制方程對每個試件的EIFS值進行計算并初步評估,驗證了在不同應力水平下緊固孔結構細節的EIFS無顯著性差異;得到了緊固孔結構細節的裂紋萌生時間(TTCI)分布,在指定應力水平下對緊固孔結構細節95%置信水平下的經濟壽命進行預測,并與設計壽命進行對比,提出了一種不同超越概率P下的結構細節當量初始缺陷尺寸模型,基于給定5%的裂紋超越概率,對結構細節的通用EIFS分布進行評估。通過以上對飛機機翼緣條緊固孔細節原始疲勞質量的三重評估,得到綜合評估結果:飛機機翼緣條緊固孔細節原始疲勞質量滿足要求。

     

    Abstract: On analyzing the details of kinetic links of parts and structures of aircrafts, one can find few bad links. But fastener hole is the weakest link where abnormal stress is produced and initiation of crack occurs. The initial fatigue quality of aircraft wing flange fastener is the key parameter, which affects the durability of aircraft structure. The initial fatigue quality of structural details is usually characterized by the equivalent initial defect size (EIFS) and the time to crack initiation (TTCI). To evaluate the initial fatigue quality of aircraft wing flange fastener hole details, this paper first carried out fatigue tests at high-, medium- and low-stress levels on the BXXX aluminum alloy fastener hole specimens generally used in aircraft wing flange structures, and obtained three groups of (a?t) datasets about crack length a and fatigue life t through fracture interpretation and back stepping. On this basis, the EIFS governing equation was used to evaluate the EIFS value of each specimen, and it is found out that there is no significant difference in equivalent initial flaw size under different stress levels; TTCI distribution of structural details is obtained, and the economic life of specified stress level under 95% confidence level of fastener hole structural details was predicted, and compared with the design life; a structural detail equivalent to initial flaw size model under different exceedance probability P was proposed. Based on the given 5% crack exceedance probability, the general EIFS distribution of structural details was evaluated. The comprehensive evaluation results were obtained through the above triple evaluation of the initial fatigue quality of the fastener hole details: the general EIFS distribution and the EIFS value of each test piece are less than the allowable value, and the economic life is greater than the allowable value, so the original fatigue quality of the details of the fastening holes of the aircraft flange meets the stringent requirements.

     

/

返回文章
返回
<th id="5nh9l"></th><strike id="5nh9l"></strike><th id="5nh9l"><noframes id="5nh9l"><th id="5nh9l"></th><strike id="5nh9l"></strike>
<progress id="5nh9l"><noframes id="5nh9l"><th id="5nh9l"><noframes id="5nh9l">
<th id="5nh9l"></th> <strike id="5nh9l"><noframes id="5nh9l"><span id="5nh9l"></span>
<progress id="5nh9l"><noframes id="5nh9l"><span id="5nh9l"><noframes id="5nh9l"><span id="5nh9l"></span><strike id="5nh9l"><noframes id="5nh9l"><strike id="5nh9l"></strike>
<span id="5nh9l"><noframes id="5nh9l">
<span id="5nh9l"><noframes id="5nh9l">
<span id="5nh9l"></span><span id="5nh9l"><video id="5nh9l"></video></span>
<th id="5nh9l"><noframes id="5nh9l"><th id="5nh9l"></th>
<progress id="5nh9l"><noframes id="5nh9l">
259luxu-164