表面技术
錶麵技術
표면기술
Surface Technology
2015年
9期
96-101
,共6页
范博楠%张玉波%王海斗%徐滨士%赵杨
範博楠%張玉波%王海鬥%徐濱士%趙楊
범박남%장옥파%왕해두%서빈사%조양
裂纹分布%裂纹深度%叶片%共振%弯曲振动%高周疲劳
裂紋分佈%裂紋深度%葉片%共振%彎麯振動%高週疲勞
렬문분포%렬문심도%협편%공진%만곡진동%고주피로
location of cracks%depth of cracks%blade%resonance%flexural vibration%high-cycle fatigue
目的:研究叶盘叶片进气及出气边萌生的横向贯穿型裂纹的分布位置及深度变化对叶片一阶弯曲振动特性的影响。方法根据叶片尺寸及工况建模,得到正常叶片在静止及不同旋转速度下的一阶振动频率,并进行拟合。在正常叶片模型的基础上,通过布尔运算建立裂纹模型,研究横向贯穿型裂纹在不同分布位置及不同深度下对一阶弯曲振动频率的影响,并进行拟合。针对裂纹深度变化采集的定时信号通过DFT变换,得到正常及含有不同深度裂纹叶片的一阶频率,对建模结论进行验证。结果一阶弯曲振动频率先减小后增大,在距离叶根4.23 mm时为最小值801.16 Hz;当裂纹距叶根的距离大于35 mm时,振动频率先接近后大于正常叶片,振幅先接近后小于正常叶片,最终将35 mm设定为位置的阈值;裂纹深度的增加使振动频率单调减小,且速率不断增大。采集的信号经DFT变换得到的一阶弯曲振动频率与建模结果的误差分别为1.9%,2.0%,1.5%,0.6%。结论当叶片进气或出气边位置阈值内出现裂纹萌生及扩展时,一阶弯曲振动频率会小于正常值,此时叶片的一阶弯曲共振区域会增大,需要对旋转机械进行严格的工况监测,同时裂纹深度的增加可提高叶尖定时监测的准确性。
目的:研究葉盤葉片進氣及齣氣邊萌生的橫嚮貫穿型裂紋的分佈位置及深度變化對葉片一階彎麯振動特性的影響。方法根據葉片呎吋及工況建模,得到正常葉片在靜止及不同鏇轉速度下的一階振動頻率,併進行擬閤。在正常葉片模型的基礎上,通過佈爾運算建立裂紋模型,研究橫嚮貫穿型裂紋在不同分佈位置及不同深度下對一階彎麯振動頻率的影響,併進行擬閤。針對裂紋深度變化採集的定時信號通過DFT變換,得到正常及含有不同深度裂紋葉片的一階頻率,對建模結論進行驗證。結果一階彎麯振動頻率先減小後增大,在距離葉根4.23 mm時為最小值801.16 Hz;噹裂紋距葉根的距離大于35 mm時,振動頻率先接近後大于正常葉片,振幅先接近後小于正常葉片,最終將35 mm設定為位置的閾值;裂紋深度的增加使振動頻率單調減小,且速率不斷增大。採集的信號經DFT變換得到的一階彎麯振動頻率與建模結果的誤差分彆為1.9%,2.0%,1.5%,0.6%。結論噹葉片進氣或齣氣邊位置閾值內齣現裂紋萌生及擴展時,一階彎麯振動頻率會小于正常值,此時葉片的一階彎麯共振區域會增大,需要對鏇轉機械進行嚴格的工況鑑測,同時裂紋深度的增加可提高葉尖定時鑑測的準確性。
목적:연구협반협편진기급출기변맹생적횡향관천형렬문적분포위치급심도변화대협편일계만곡진동특성적영향。방법근거협편척촌급공황건모,득도정상협편재정지급불동선전속도하적일계진동빈솔,병진행의합。재정상협편모형적기출상,통과포이운산건립렬문모형,연구횡향관천형렬문재불동분포위치급불동심도하대일계만곡진동빈솔적영향,병진행의합。침대렬문심도변화채집적정시신호통과DFT변환,득도정상급함유불동심도렬문협편적일계빈솔,대건모결론진행험증。결과일계만곡진동빈솔선감소후증대,재거리협근4.23 mm시위최소치801.16 Hz;당렬문거협근적거리대우35 mm시,진동빈솔선접근후대우정상협편,진폭선접근후소우정상협편,최종장35 mm설정위위치적역치;렬문심도적증가사진동빈솔단조감소,차속솔불단증대。채집적신호경DFT변환득도적일계만곡진동빈솔여건모결과적오차분별위1.9%,2.0%,1.5%,0.6%。결론당협편진기혹출기변위치역치내출현렬문맹생급확전시,일계만곡진동빈솔회소우정상치,차시협편적일계만곡공진구역회증대,수요대선전궤계진행엄격적공황감측,동시렬문심도적증가가제고협첨정시감측적준학성。
Objective To research the effect of the location and depth of the lateral and penetrating cracks initiating at the lead-ing or trailing edge of the disk blades on the frequency of the first-order flexural vibration of the blades. Methods The frequencies of normal blades in static and rotation were calculated through modeling according to the size and working condition, then the mod-els for lateral and penetrating cracks were built by Booleans operation on the basis of normal blades to research the variation of fre-quencies affected by location and depth of the lateral and penetrating cracks and all the data was fitted. The modeling results were verified by the frequencies of the first-order flexural vibration of normal blades and those with different crack depth through DFT a-nalysis of BTT signals. Results The results showed that the frequency decreased at first and then increased. The minimum frequen-cy of 801. 16 Hz was got at the distance of 4. 23 mm. When the distance to the root was greater than 35 mm, the frequency became close to and then greater than the normal value, so the distance of 35 mm was set as the threshold of location. In addition, the fre-quency decreased with the increase of the crack depth, and the speed of changing kept increasing. The measurement errors of BTT signals with the results of FEM were 1. 9%, 2. 0%, 1. 5% and 0. 6%, respectively. Conclusion When cracks initiate at the lead-ing or trailing edge within the location threshold, the frequencies of the first-order flexural vibration are lower than the normal val-ues, and the resonance region of first-order flexural vibration will expend so that the working condition needs to be monitored seri-ously. Meanwhile, the increase of the crack depth can improve the accuracy of BTT data.