模态分析的通俗解释

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1、MODALSPACE-INOUROWNLITTLEWORLD模态空间–在我们自己的小世界中              PeteAvitabile著 westrongmc译Couldyouexplainmodalanalysisforme?Well...itwilltakealittlebitbuthere'sonethatanyonecanunderstand.你能为我解释模态分析吗？嗯…说来有点话长，但下面的解释人人都可理解。You'renotthefirstonetoaskmetoexplainmodalanalysisin

2、simpletermssoanyonecanunderstandit.Inanutshell,wecouldsaythatmodalanalysisisaprocesswherebywedescribeastructureintermsofitsnaturalcharacteristicswhicharethefrequency,dampingandmodeshapes-itsdynamicproperties.Wellthat'samouthfulsolet'sexplainwhatthatmeans.Withoutgetti

3、ngtootechnical,Ioftenexplainmodalanalysisintermsofthemodesofvibrationofasimpleplate.Thisexplanationisusuallyusefulforengineerswhoarenewtovibrationsandmodalanalysis.请我用简单的概念来解释模态分析，以便任何人都可以理解它，你不是第一个人。简言之，模态分析是一种方法，籍此，可以根据结构的频率、阻尼和振型等固有属性-其动态特性-来描述结构。这真够拗口的，那我们来解释这是什么

4、意思。不钻技术牛角尖，我经常用一个简单平板的振动模态来解释模态分析。对于刚接触振动及模态分析的工程师们来讲，这种解释向来有益。Let’sconsiderafreelysupportedflatplate.Let'sapplyaconstantforcetoonecorneroftheplate.Weusuallythinkofaforceinastaticsensewhichwouldcausesomestaticdeformationintheplate.ButherewhatIwouldliketodoistoapplyaf

5、orcethatvariesinasinusoidalfashion.Let'sconsiderafixedfrequencyofoscillationoftheconstantforce.Wewillchangetherateofoscillationofthefrequencybutthepeakforcewillalwaysbethesamevalue-onlytherateofoscillationoftheforcewillchange. Wewillalsomeasuretheresponseoftheplatedu

6、etotheexcitationwithanaccelerometerattachedtoonecorneroftheplate.考虑一个自由支撑平板，施加常力于平板一角。我们通常从静态的意义上来看待一个力，它在平板内引起某种静态变形。但这里我要做的是施加一个按正弦方式变化的力，振荡频率固定的常力。我们将改变振荡频率，但不改变力的峰值-仅是力的振荡频率改变。另在平板一角安装一加速度计来测量激励引起的平板响应。Nowifwemeasuretheresponseontheplatewewillnoticethattheamplitu

7、dechangesaswechangetherateofoscillationoftheinputforce.Therewillbeincreasesaswellasdecreasesinamplitudeatdifferentpointsaswesweepupintime.Thisseemsveryoddsinceweareapplyingaconstantforcetothesystemyettheamplitudevariesdependingontherateofoscillationoftheinputforce.Bu

8、tthisisexactlywhathappens-theresponseamplifiesasweapplyaforcewitharateofoscillationthatgetscloserandclosertothenaturalfrequency(orr