简介:ARM微处理器及技术还应用到许多不同的领域,ARM7系列微处理器为低功耗的32位RISC处理器,采用RISC架构的ARM微处理器一般具有如下特点
简介:Largeamplitudevibrationofmastarmstructuresduetowindloadsaretheprimarycontributingfactortothereducedfatiguelifeofsignalsupportstructures.Toalleviatethisproblemofwind-inducedin-planevibrationofmastarmsignalstructures,aparticle-thrustdampingbasedturnedmassdamper(PTD-TMD)deviceisadoptedanditsdampingeffectischaracterizedexperimentally.Theparticle-thrustdampingisapassivedampingdevicethatdoesnotrequireelectricpowerandistemperatureindependent.Basedonthecalibrationtest,anequivalentdynamicmodelofthePTD-TMDdeviceisdevelopedandusedfornumericalsimulationstudy.ThedampingeffectsofthisPTD-TMDdeviceonsignalsupportstructureswasinvestigatedthroughbothnumericalanalysisandlaboratorytestingofa50-ft(15.24m)mastarmstructureincludingbothfreevibrationandforcedvibrationtests.TheexperimentaltestandnumericalstudyresultsshowthatvibrationresponsebehaviorofmastarmsignalsupportstructurescanbesignificantlyreducedbyinstallingthePTD-TMDthatcanincreasethecriticaldampingratioofthemastarmsignalstructuresto4%.Thestressrangeattheweldedconnectionbetweenthemastarmandtrafficpoleisalsoreduced.