£10,000 Fatigue Tester

Press, Volume CVI, Issue 31343, 13 April 1967, Page 19

£10,000 Fatigue Tester

A £lttOOO U.H.5.6 universal testing machine will be started officially in the mechanical engineering department of the University qf Canterbury on Friday. The ceremony will be performed by Professor J. Packer, a member of the University Research grants Committee, which provided the funds. “Fatigue is/the catastrophic fracture of k machine component or fracture as a result of sewice load fluctuations or loju reversals. There are many Jay-to-day examples of fatigue/failures, but since they areilo common few are brought to notice,” said Mr L. A. Easmus, a lecturer in the dep/tment “The/Comet crashes in the early »50s, the Christchurch crash jnf a Bristol Freighter in 19», and the more recent failu* of Kiig’s bridge in Mellpurne are prominent examines of fatigue fractures. "I recent survey suggested tha fatigue fractures were

costing Britain £lOO million a year, and that this figure is expected to rise as industrial processes are speeded up.” The university mechanical engineering department has been doing research in fatigue of metals for a number of years. There are now 12 smaller fatigue machines available for research work and student instruction. Eventually it is hoped to have three machines the size of the new one in the laboratory. “In view of the high cost, the Research Grants Committee cannot provide unlimited financial support. Industry will have to be approached for support,” said Mr Erasmus. Fatigue specimens were usually tested in groups of 15 to 20, and within each group at least four specimens might be expected to last for 100,000,000 stress cycles. Each group of specimens therefore took six months to complete. Since a modest research programme might have upwards of 10 such groups of specimens to test, there was a need for two additional large fatigue machines, he said.

When testing time was available, the facilities of the department would continue to be at the service of other institutions and firms interested in fatigue. Because of the high cost of equipping a fatigue laboratory, and the specialist knowledge required to operate it, it would be uneconomical if there had to be more than one major fatigue laboratory in New Zealand, Mr Erasmus said. The chemistry division of the D.S.I.R. had been using the laboratory over the last year to enable a member of its staff to do post-graduate work on corrosion fatigue. Requests for testing time had also been received from the Department of Civil Aviation and the Electricity Department. The fatigue programme also required an electron microscope so that the micro-struc-ture of metals could be examined at very high magnification and with great clarity. The initiation and propagation of fatigue cracks could then be examined in great detail.

Mr Erasmus said a Golden Kiwi grant of £2OOO had already been received by the mechanical engineering department towards a mediumsized electron microscope. It was hoped that the remaining £7500 would be obtained this year. This instrument would become the first in New Zealand to be fully employed on research into metallic materials, Eleven electron microscopes would soon be employed on biological research in this country. The different requirements of biological and metallic materials research made it necessary to have separate electron microscopes, so that the need for one in the department remained urgent, he said. The photograph shows Mr Erasmus (left) with Mr E. Koerner, the German engineer who installed the machine. Specimens are placed between the black grips of the unit at the right and results are read on the panel at the left