Infoplaner 1-2007 - Cadfem

CADFEM INFOPLANER 1/2007Thermal Analysis and Seismic Analysisof a 12 m Antenna StructureThermal AnalysisImagine the sunrise at the foothills of Chile‘s Andes mountains.The wind blows slowly through the dry Atacamadesert…This scenario isn’t based on the fantasy of a lonely adventurerbut the given thermal load case for the design of one of thetelescopes of the ALMA (Atacama Large Millimeter Array)project. In corporation with VERTEX Antennentechnik GmbHa complex thermal analysis has been performed by CADFEMConsulting.14Due to the given specifications the antenna had to be analyzedconsidering sun radiation, outgoing radiation andof course the convective heat transfer to the environment.Taking into account the heat transfer effects• heat conduction• heat convection• heat radiationit was possible to determine the temperature field of theantenna. Both steady state and transient analysis gives valuableinformation about the resulting thermal loads to thestructure. Special care had to be taken into account for thelaminated CFRP structure. By idealization of the CFRP materialproperties many simplifications could be done. As a specialchallenge the thermal analysis of the convective heat transferpart to the environment hasbeen combined with a CFDanalysis. Therefore also thewind influence onto the temperaturefield of the antennahas been computed.The resulting temperaturefield can be used for subsequentstructural analyses todetermine thermal deformationor critical thermal stresszones.Seismic Analysis: Singlepoint response spectrum(SPRS) analysis in ANSYSA seismic analysis is frequentlyrequired for largebuildings or other tall structuresparticularly at locationsin seismic active regions. Forthat purpose FE analysis isapplied to proof the integrityof the structure during anearthquake. Here, the 12mALMA (Ata-cama Large MillimeterArray) telescope (Fig.1) has been analyzed.Solution by means ofANSYSA response spectrum for thegiven earthquake location isFig. 1: ALMA 12 m telescope.Sun load at the structureApplications and Technology