A programme of tensile testing with a difference was recently completed at TWI for the Japan Research and Development Center which is working closely with the TWI Industrial Member, Nippon Steel Corporation.
The tests were carried out within a pressure vessel containing high purity hydrogen, at a pressure of 450barg. They were performed at both ambient temperature and 85°C.
The work, in conjunction with similar testing in Japan by NSC, provides input to Japanese planning for the hydrogen economy. In particular, test data are required to ensure the safe performance of hydrogen storage and handlingsystems for automotive applications, on board vehicles.
The facility to house and service the mechanical test machine and pressure vessel was designed and built over some eight months, and the tensile test programme was then completed. Following the successful development and use of thisequipment, a second equipment development phase was recently initiated to provide a complementary and more advanced testing facility.
While TWI's existing equipment operates at 450bar and in the temperature range of ambient to 85°C, the new test chamber is designed to enable testing at 1000bar and between 85°C to -150°C. And while tensile andfatigue testing can already be carried out, TWI's new equipment will enable additional tests to be executed, such as fracture toughness testing.
The new test vessel is now in the design stage, with installation and commissioning due for completion in 2007. Working with TWI, manufacturers will have an opportunity to carry out research and development work in a facility thatis unique within Europe.
The new installation is located in an isolated building, which is also scheduled to house an existing elevated temperature hydrogen autoclave (for disbonding testing and hydrogen charging) which is being re-located on the Abingtonsite.
The building has a test booth for each pressure vessel, and a control room separated from these by steel doors, with a safety interlock. The roof over the test booth is of lightweight construction, and would provide an easy path forany sudden pressure release or explosion. The combination of interlocks, gas and fire detectors and procedures, however, make this an extremely unlikely event.
The existing test vessel, is about 125mm thick and made out of solid 316 stainless steel. There is a load cell inside the pressure vessel, which has to tolerate the pressure cycling, and hydrogen atmosphere.
The test vessel is mounted within a standard 100kN servohydraulic load frame.
An electronic control system manages automatic purge, fill and empty cycles, operated by pneumatic valves through a simple control panel.
For further information on testing in hydrogen, please contact automotive@twi.co.uk
