极端环境条件下大跨越输电塔线体系的动态响应分析

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1、摘要极端环境条件下大跨越输l也塔线体系的动态响应分析舞动关键词：大跨越输电塔线体系：极端环境条件；有限元法；龙卷风；地震：lI作者：任超指导教师：高强DynamicResponseAnalysisofLongSpanTransmissionTower-lineSystemUnderExtremeEnvironmentalConditionsAbstractLongspantransmissiontower-linesystemisavitallifelinetopowersystem．Exposinginenvironme

2、nt，thesystemmustberobustenoughtobeardestructiveforceinextremeenvironmentalconditions．Thetowermaycollapseunderextremeenvironmentalloadingsuchastornado，earthquake，snowandicedisaster．Theicedtransmissionlinegallopingmayoccuredalso．Theseaccidentsinfluencethesafetyofpow

3、ersystemseriously．Inthispaper,dynamicresponseoflongspantransmissiontower-linesystemunderextremeenvironmentalconditionsisanalyzedbyfiniteelementmethod．Theanalysisresultsareprovidedforelectricitysectorandtheyarehelpfulforon-linemonitoringoftower-linesystem．Firstly,a

4、f'miteelementmodeloflongspantransmissiontower-linesystemisbuilt．Modalanalysisisdoneondifferentmodels，suchasspantower,anchortower,andtower-linesystem．Naturalmodesandfrequenciesareextracted．Theresultsshowthatnaturalfrequencyvalueofspantowerreduceswhenelevatorwellhol

5、eisconsidered．However,thevaluereducesmuchmorewhentransmissionlineandanchortowersareallconsidered．Secondly,staticanddynamicresponseanalysisoflongspantransmissiontowerundertomadoloadingiscalculated．Materialnonlinearityisconsideredandthreedifferentcasesofwindloading(

6、towersurfaceandwindvelocityareat0。、45。、90。angle)arediscussed．Deformationandstressareobtained．TheresultsshowthattowerissafeunderF2gradetornadoinstaticanalysis．Ontheotherhand，plasticdeformationcausestowerdamagedindynamicanalysiswithamaximumwindvelocity100rrds．Howeve

7、r,thedeformationandstressaremoresignificantin45。anglecaseeitherinstaticordynamicanalysis．Thirdly,time-historyanalysisoftowerunderearthquakeloadingisstudiedtoobtaindeformationandstressofstructure．Theresultsshowthatdeformationinhorizontaldirectionismajorandthevalueg

8、etslargerasheightincreases．MaximumIIIstressoftowerislowerthanultimatewhichrevealsthatthetowerhasagoodresistanceinVIImagnitudeintensityearthquake·Finally