Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 1 Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas Antenna Seismic Verification PM# May 2006 Dated November 18 h, 2005

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 2 Antenna Seismic Verification References: ► Eurocode 8, Design provisions for earthquake resistance of structures ►ALMA Environmental Specification:ALMA B-SPE ►FEM Model: ANTD C-FEM

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 3 ►The Antenna Seismic Verification has been performed by a FEM Spectrum Analysis ►Steps in a Spectrum Analysis: ►Obtain the natural frequencies and mode shapes of the structure by performing a Modal Analysis ►50 natural frequencies and modes up to 35 Hz have been considered

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 4 ►Given the Response Spectrum, calculate the Modal Response of each mode ►Single Point Response Spectrum Analysis ►A unique Excitation has been applied to the Antenna foundations ►Combination of the seismic action components according to Eurocode 8 ►Calculate the Total Modal Response of the whole structure by combining the Modal Response of each mode ►SRSS (Square Root of the Sum of the Squares) Method

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 5 According to Eurocode 8: ►Combination of the horizontal component of the seismic action: a.E x “+” 0.30E y b.0.30E x “+” E y ►The vertical component of the seismic action has to be taken in account only in some cases (i.e. for cantilever elements) ►it will be considered only for the platforms sub-assembly ►ALMA response spectrum from environmental specification

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 6 Global FEM Model ANTD C-FEM Natural frequencies and modes no.50, up to 35 Hz Spectrum Analysis typeSingle Point Response Spectrum Combination of the seismic action components Eurocode 8 Combination of the Modal Response of each single mode SRSS (Square Root of the Sum of the Squares) Method

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 7 ►Natural frequencies and modes have been calculated up to 50 th mode – 35 Hz ALMA - Spectrum Analysis.xls

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 8 1 st natural mode, cabin floor 2 nd natural mode, global x MODAL ANALYSIS

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 9 4 th natural mode, global y 35 th natural mode, global z MODAL ANALYSIS

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page th natural mode 9 th natural mode, 2 nd global torsional vibration 8 th natural mode, 1 st global torsional vibration MODALANALYSISMODALANALYSIS

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 11 8 th natural mode, torsional vibration (with legs) MODAL ANALYSIS 10 th natural mode 3 rd natural mode

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 12 Total Response, displacement in x direction ANTENNA MODAL RESPONSE Total Response, displacement in y direction Total Response, displacement in z direction

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 13 Total Response, displacement vector plot Total Response, resultant displacement contour plot ANTENNA MODAL RESPONSE

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 14 Total Response, Von Mises stress contour plot Elevation Membrane, Von Mises stress contour plot σ VM,max =97.3 MPa  Y =480/97.3=4.9 ANTENNA MODAL RESPONSE σ VM,max <10 MPa

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 15 Foundation interface block, Von Mises stress contour plot σ VM,max =55 MPa ANTENNA MODAL RESPONSE

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 16 Azimuth bearing, Von Mises stress contour plot Saddle, Von Mises stress contour plot σ VM,max =20 MPa σ VM,max =41 MPa ANTENNA MODAL RESPONSE

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 17 BUS – Legs interface, Von Mises stress contour plot σ VM,max =5 MPa ANTENNA MODAL RESPONSE

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 18 Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas Antenna Seismic Verification PM# May 2006 Dated November 18 h, 2005

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 19

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 20