Performance-Based Engineering for Lunar Settlements

Transcription

1 Performance-Based Engineering for Lunar Settlements Haym Benaroya LEAG Conference on Lunar Exploration 2005 M E C H A N I C A L & A E R O S P A C E Houston 26 October 2005

2 Contents I. Back to the Moon II. III. IV. Mining, Tourism, etc. Concepts & Designs Performance-Based Engineering V. Decision Variables

3 New Space Programs President Bush s new vision for NASA plans to return astronauts to the Moon by 2018(?). The Chinese Chang e program plans human missions to the Moon after The European Space Agency s Aurora program intends to send humans to the Moon by 2024.

4 Moon First! attract young people to engineering & science benefit from dual-use technologies reasonable accessibility from Earth astronomy resources geology stepping stone to Mars survival of the species

5 areas of permanent sunlight solar cells can be made from local materials no atmosphere power beaming back to Earth Energy Production

6 fuel cells need platinum as a catalyst not enough platinum resources on Earth to replace all engines in the US with fuel cells Apollo data show that the Moon is rich in platinum Mining

7 Tourism Hilton/Marriott Courtesy Peter Inston

8 Structural Design Loads 1/6 gravity Internal air pressurization Regolith shielding Dynamic loads from operating machinery Accidental loads like vehicle impacts Extreme temperature gradients Decompression Hard vacuum

9 Design Consequences internal pressure will govern structural design optimize structure accordingly take depressurization into account make sure construction feasible

10 Structural Concepts first generation: pre-fabricated and pre-outfitted modules like the ones for the ISS

11 second generation: locally assembled structures after a certain presence on the Moon has been established third generation: structures exclusively made from local materials Structural Concepts

12 Structural Concepts Second generation habitats: M. Criswell inflatable structures cable structures rigid structures A. Eichold

13 Generation-1.5 Proposed Design: A Tied-Arch Shell Structure Concept and picture by F. Ruess and H. Benaroya

14 Structural Analysis rise: 5 m rise regolith modulus of subgrade reaction: 1000 kpa / m global safety factor applied: 5

15 Design Loads

16 Cross Sections: Summary most efficient cross section material: high-strength aluminum arch mass: 31 kg / m² average floor mass: 118 kg / m² max. deflections for operational loads are about 5 cm

17 Hinged Connections Concept: Jörg Schänzlin

18 The Construction Sequence

19 Overview PBE I. Hazard Analysis II. III. Structural Analysis Damage Analysis IV. Loss Analysis PBE addresses system-level performance in terms of risk of significant event, fatalities, repair costs, and post-event loss of function. Design process is structured to meet specific performance expectations of the structure s occupants, owner and public.

20 I. Hazard Analysis Hazard analysis results in frequencies of occurrence of key events: meteorites radiation accidents/malfunctioning aging/degradation

21 II. Structural Analysis Analysis in terms of system and component uncertainties: structural member strength and geometric properties soil mechanics loads analysis site data analysis mathematical/computational modeling assumptions

22 III. Damage Analysis Fragility curves are used to probabilistically model damage. Fitting a Lognormal distribution to the sample CDF of peak displacements Fragility curves North wall, showing effects of partition walls and finish materials (1% drift limit) Pf OSB only (without Partition Walls) OSB + GWB (without Partition Walls) OSB + GWB + Stucco (with Partition Walls) OSB + GWB (with Partition Walls) Structure Type: One Story (32' 20') Nailing Schedule: 8d@6"-12" Sheathing: OSB ( 3 / 8 ") Shearwall HP: Durham + CASHEW NSF: GWB + Stucco Damping: 1% W = kn total (varies) S a (g) 26

23 IV. Loss Analysis Frequency and probability data can be used to extract performance metrics that are meaningful to facility stakeholders, metrics such as upper bound economic loss during the owner-investor s planning period. Now risk-management decisions can be made.

24 Performance-Based Engineering Covers range of hazard levels Accounts for uncertainty in parameters, relationships Decision variable Damage measure Engineering demand parameter Intensity measure λ = DV DM dg DM EDP dg EDP IM dλ DV G IM Cost of repair Or Loss of Function Structural or non- Structural Damage Forces, Displ, Temp. Input Spectra After: Kramer, Mayfield and Mitchell, Ground Motions and Liquefaction