International Conference on Hydrogen Safety 9/12/2011 P. Pöschko, G. Mair, BAM-3.2

1. RESEARCH ON RC&S FOR HYDROGEN STORAGE RELEVANT TO TRANSPORT AND VEHICLE ISSUES WITH SPECIAL FOCUS ON COMPOSITE CONTAINMENTS International Conference on Hydrogen Safety 9/12/2011 P. Pöschko, G. Mair, BAM-3.2

2. Structure Division 3.2– Pöschko, Mair • Aspects of CC prospective design evaluation: Probabilistic Approval Approach • Assessment of continued CC safety performance: Testing Parallel to Operation • Quantification of CC residual strength properties: Techniques and Strategy

3. Probabilistic Approval Approach Division 3.2– Pöschko, Mair Mathematical analysis of GAUSS log-standard deviation based on 25,000 LC mean value

4. Probabilistic Approval Approach Division 3.2– Pöschko, Mair Safe number of fillings depending on mean values of fatigue figures

5. Testing Parallel to Operation Division 3.2– Pöschko, Mair • Degradation of H2G CC composite materials is subject to a variety of in-service conditions  increasing uncertainties in safe life behavior/ residual service life determination • Static loads (creep) are largely responsible for progressive loss of strength  difficulty of predictability, even if underlying mechanisms were well understood Monitoring seems essential, especially in the face of “unlimited“/several decades‘ service lives

6. Testing Parallel to Operation Division 3.2– Pöschko, Mair Principle for the assessment of safe service lives 99.99% Schematic diagram for the determination of safe service lives, with degradation lines assumed to run linearly

7. Techniques and Strategy Division 3.2– Pöschko, Mair • NDT methods are not yet sophisticated enough to reliably monitor CC populations  necessity of destructive test procedures (key tests) e. g. 15 y … e. g. 15 y Beginning of life/production End of originally granted service life Key tests on sample of used CC Key tests on sample of used CC Design type approval & original batch tests Possible life time extension Comparison and safe life assessment Possible early rejection

8. Techniques and Strategy Division 3.2– Pöschko, Mair • Appropriate testing techniques must account for expected in-service loads and respective damage mechanisms, both for design type approval and parallel to operation: • Cycle tests appear adequate for most designs with metal liners, but • Aspects of creep rupture cannot be simulated in a satisfactory manner at present, making assessment of type IV designs a particular challenge Discrimination between load cycle sensitive and non-sensitive designs, requires new techniques!

9. Techniques and Strategy Division 3.2– Pöschko, Mair Influence of constant pressure increase rate on burst pressure for one specific design Z1

10. Techniques and Strategy Division 3.2– Pöschko, Mair Strength of artificially aged cylinders in comparison with new cylinders of design Z2

11. Summary and Outlook Division 3.2– Pöschko, Mair • Given the complexity of CC designs, current RC&S need improvement with regard to testing procedures and periodic retesting • Unspecific requirements suggest there is potential for cost and weight optimization, depending on the materials and CC design • Destructive testing parallel to operation can provide useful information in order to evaluate service life time determinations • Slow burst techniques will be further developed to allow for better assessment of long-term behavior

12. RESEARCH ON RC&S FOR HYDROGENSTORAGE RELEVANT TO TRANSPORT AND VEHICLE ISSUES WITH SPECIAL FOCUS ON COMPOSITE CONTAINMENTS RESEARCH ON RC&S FOR HYDROGENSTORAGE RELEVANT TO TRANSPORT AND VEHICLE ISSUES WITH SPECIAL FOCUS ON COMPOSITE CONTAINMENTS Please ask your questions now… International Conference on Hydrogen Safety 9/12/2011 P. Pöschko, G. Mair, BAM-3.2