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Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas FEM Structure Distortion Analysis PM#7 , 2006. FEM Mechanical Model FE deformation Analysis Flow. Structural FE ANSYS Model. Wind Analysis (FLUENT). Pressures. Translation. FE NASTRAN Model. Mapping.
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Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas • FEM Structure Distortion Analysis • PM#7 , 2006
FEM Mechanical Model • FE deformation Analysis Flow Structural FE ANSYS Model Wind Analysis (FLUENT) Pressures Translation FE NASTRAN Model Mapping Interfacing Tools FEM Deformation Analyses Thermal Analysis (THERMICA/ESATAN) Temperatures Displacements Rotations ERROR BUDGET Input
FEM Mechanical Model • New Ansys FEM has been converted into MSC.NASTRAN • Previously defined procedures and rules have been applied (e.g. avoiding of drilling stiffness, re-modelling of entities not automatically translated as springs, rigid links and lay-up orientations) • Re-modelling changes are as agreed previouslywith EIE • Coherence between Ansys and Nastran FEM is demonstrated by comparison of the results
FEM Mechanical Model • Normal Modes Analysis • NMA was carried out as preliminary check of NASTRAN Model • Results of Nastran Model are the same than Ansys model Scale Factor: 100 Mode#2 - Frequency 8.89 Hz
FEM Mechanical Model • MSC.NASTRAN analyses models • Reference FEM model have been rotated about both Elevation and Azimuth Axis • 15 antenna configurations required by different analyses kind have been obtained 0° Azimuth 0° Elevation 0° Azimuth 0° Elevation 60° Azimuth 0° Elevation 45° Azimuth 45° Elevation
FEM Mechanical Model – Gravity Deformation analysis • 7 ANALYSIS CASES of self-weight • Azimuth 0°, Elevation 0°-15°-30°-45°-60°-75°-90° Deformation under gravity load Azimuth 0°- Elevation 90° Deformation under gravity load Azimuth 0°- Elevation 60° Deformation under gravity load Azimuth 0°- Elevation 0°
FEM Mechanical Model – Wind Deformation Analysis • Mapping of FLUENT Pressure into NASTRAN FEM using Hypermesh DLM • 11 Analysis cases + 15 Addionals Cases • Wind load on Apex Legs have been introduced as a Static Force Elevation Structure CFD MODEL STRUCTURAL MODEL Forces on APEX Legs Apex Structure Apex Structure
FEM Mechanical Model – Wind Deformation analysis • 11 ANALYSIS CASES - Primary Cond. Night Time • Azimuth 0° - 60° - 120° - 180°, Elevation 0° • Azimuth 45° - 135°, Elevation 45° • Azimuth 0° - 90° - 180°,Elevation 60° • Azimuth 0° - 90°, Elevation 90° Deformation Azimuth 0°- Elevation 0° Deformation Azimuth 135°- Elevation 45° Deformation Azimuth 180°- Elevation 60°
FEM Mechanical Model – Thermal Deformation Analysis • Mapping of THERMICA/ESATAN Temperature into NASTRAN FEM • Using Thermal Desktop and Nastran Heat Tranfer Capabilities STRUCTURAL MODEL THERMAL MODEL
FEM Mechanical Model - Thermal Deformation Analysis • 6 ANALYSIS CASES • Max temp diff. Hot 1 • Max temp diff. Cold 1 • Max temp gradient Y • Max temp gradient Z • Max temp gradient X • Max temp diff. Hot 2 Deformation under thermal load Max temp Gradient X Deformation under thermal load Max temp diff. Hot 1
FEM Mechanical Model – Error Budget Input Data • Reference points – Displacements & Rotations BUS Parabola Metrology Points Receiver Tiltmeters 600 reference points 192 reference points Tiltmeter 2 reference points ERROR BUDGET Tiltmeter 3 addittional points