振动与冲击
振動與遲擊
진동여충격
JOURNAL OF VIBRATION AND SHOCK
2014年
2期
193-198
,共6页
腐蚀疲劳%Q345 等边角钢%单点-似然法%相关系数优化法%回归分析
腐蝕疲勞%Q345 等邊角鋼%單點-似然法%相關繫數優化法%迴歸分析
부식피로%Q345 등변각강%단점-사연법%상관계수우화법%회귀분석
corrosion fatigue%Q345 equal angles%single-point likelihood method%optimization method of correlation coefficient%regression analysis
针对角钢构件在输电塔线体系服役期间因环境腐蚀与风致振动耦合作用导致疲劳性能退化,而构件腐蚀疲劳试验成本高、耗时久、难度大等限制因素所致试验资料匮乏问题,基于节省成本、提高精度思路,结合单点-似然法与相关系数优化法,提出确定腐蚀疲劳S-N曲线表达式参数的改进回归分析方法,构造与之对应的实现算法,建立随腐蚀时间变化的t-P-S-N曲面表达式;通过三组不同腐蚀时间的18根足尺试件疲劳试验,研究Q345等边角钢腐蚀疲劳破坏模式,分析P-S-N曲面方程中各参数随腐蚀时间的变化规律,并结合理论分析建立Q345等边角钢构件t-P-S-N曲面模型。采用该模型探讨不同腐蚀时间内Q345等边角钢构件疲劳寿命的变化规律。结果表明,相同疲劳荷载水平作用下试件疲劳寿命随腐蚀时间急剧减小;同一腐蚀时间内疲劳寿命受腐蚀因素的影响程度随荷载的减小而增加。
針對角鋼構件在輸電塔線體繫服役期間因環境腐蝕與風緻振動耦閤作用導緻疲勞性能退化,而構件腐蝕疲勞試驗成本高、耗時久、難度大等限製因素所緻試驗資料匱乏問題,基于節省成本、提高精度思路,結閤單點-似然法與相關繫數優化法,提齣確定腐蝕疲勞S-N麯線錶達式參數的改進迴歸分析方法,構造與之對應的實現算法,建立隨腐蝕時間變化的t-P-S-N麯麵錶達式;通過三組不同腐蝕時間的18根足呎試件疲勞試驗,研究Q345等邊角鋼腐蝕疲勞破壞模式,分析P-S-N麯麵方程中各參數隨腐蝕時間的變化規律,併結閤理論分析建立Q345等邊角鋼構件t-P-S-N麯麵模型。採用該模型探討不同腐蝕時間內Q345等邊角鋼構件疲勞壽命的變化規律。結果錶明,相同疲勞荷載水平作用下試件疲勞壽命隨腐蝕時間急劇減小;同一腐蝕時間內疲勞壽命受腐蝕因素的影響程度隨荷載的減小而增加。
침대각강구건재수전탑선체계복역기간인배경부식여풍치진동우합작용도치피로성능퇴화,이구건부식피로시험성본고、모시구、난도대등한제인소소치시험자료궤핍문제,기우절성성본、제고정도사로,결합단점-사연법여상관계수우화법,제출학정부식피로S-N곡선표체식삼수적개진회귀분석방법,구조여지대응적실현산법,건립수부식시간변화적t-P-S-N곡면표체식;통과삼조불동부식시간적18근족척시건피로시험,연구Q345등변각강부식피로파배모식,분석P-S-N곡면방정중각삼수수부식시간적변화규률,병결합이론분석건립Q345등변각강구건t-P-S-N곡면모형。채용해모형탐토불동부식시간내Q345등변각강구건피로수명적변화규률。결과표명,상동피로하재수평작용하시건피로수명수부식시간급극감소;동일부식시간내피로수명수부식인소적영향정도수하재적감소이증가。
Because of the coupling between environment corrosion and wind-induced vibration,the fatigue properties of angles will degenerate during service period.From the view point of cost saving and precision improving,an improved regression method for estimating S-N curves of corrosion fatigue was proposed by combining the single-point likelihood method (SPLM)with the optimization of correlation coefficient.The implementation algorithm for the improved SPLM was also proposed.According to the improved method,an expression for the t-P-S-N surface of corrosion fatigue was presented.Meanwhile,the corrosion fatigue of three types of 18 Q345 equal angles in different corrosion time duration were tested.The corrosion fatigue failure modes of specimens were observed and the variation of P-S-N curves in different corrosion time duration was investigated.Then the t-P-S-N surface model of Q345 equal angles was achieved and the variation law of Q345 equal angles' fatigue life was obtained.It is found that the fatigue life decreases sharply with the increase of corrosion time under the same load;the effect of corrosion on fatigue life becomes more and more serious with the decrease of load in the same corrosion time.