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 FATIGUE ANALYSIS PM#05 - Toulouse June 21 th, 2006

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 2 Fatigue Assessment for ALMA Antenna  Applicable documents: Technical Specification for the design, manufacturing, transport and integration on site ALMA B-SPE  Reference documents: Design and analysis for aluminium alloy structures UNI 8634 Design and analysis for steel structures UNI ENV

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 3  The first step consists in the identification of major critical components which rupture would cause Critical or Catastrophic Hazard or preclude the functionality of antennas.  Preliminary list of critical components is shown in table 1.

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 4 Fatigue Assessment  Metallic materials Fatigue evaluation for metallic materials will be manly performed by analysis following the design rules reported in the reference normative (i.e. S-N Fatigue Curves, cumulative damage calculation)  Non Metallic and Composite Materials Fatigue evaluation for non metallic and composite materials based on fatigue analysis not applicable; Verification will be implemented in a case by case basis; however the following approach is commonly maintained: - High safety margin of strength values - Qualification tests for most critical parts (including cyclic tests). - Use of well qualified manufacturing processes. - Non destructive inspection applied on production parts.

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 5 Input for fatigue analysis  Functional and lifetime resistance requirements.  Manufacturing drawings.  Environments (temperature, humidity, wind, etc).  Materials property (S-N curves for metallic materials, tensile/compressive strength values for composite).  Detailed Stress Analysis Report.  Plan for Non Destructives Inspection on composite structure.

Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 6 Validity of Already Performed Test  Within the Prototype activities some fatigue tests were made (e.g. on reflector panels and adjusters).  In the current design it is necessary to verify by FEM analysis the stresses and deformation on the single component.  If the stresses are comparable with the ones used as a basis for the fatigue test definition, test results are still valid and there is no need to repeat them.