疲劳载荷谱B氏等效与试验验证

Equivalence of Fatigue Load Spectra Based on B-distance with Experimental Verification

疲劳试验是确定结构疲劳特性的最有效手段。为缩短疲劳试验时间,通常采用低载截除方法。相对于低载截除,载荷折算能进一步缩短试验时间,减小成本。为了能够合理地对载荷谱进行简化浓缩,本文选取了Bhattacharyya距离(简称B距离)作为衡量原谱与等效谱寿命相似程度的参量,综合考虑了寿命均值与分散性,得到浓缩后疲劳载荷等效谱。基本方法是在给定折算水平下,得到相应B距离最小的等效谱,并进行了缺口试验件的试验验证。结果表明,该方法合理有效,可大幅缩短试验时间。

Load spectra experiment is the confident way to determine the fatigue life of structures. In order to shorten the fatigue test time, small-load-omitting approach is usually used. Compared to the small-load-omitting, the load conversion can shorten the test time and reduce the cost much more. In order to simplify and concentrate the load spectra reasonably, the Bhattacharyya distance （abbreviation B-Distance） was selected as the parameter to measure the similarity of the original spectra and the edited spectra. Firstly the average life span and dispersion were comprehensively taken into consideration, and then a new method for spectra editing was proposed. The solution to the equivalent spectrum corresponding to an original spectrum which was obtained when the Bhattacharyya distance was to the minimum. An experiment was carried out on notched specimens to verify and the experimental results show that the proposed approach was reasonable and effective, which can greatly reduce the test time.