TESTING OF MATERIALS

Press, Volume LXXXVI, Issue 26122, 26 May 1950, Page 6

TESTING OF MATERIALS

NEW HYDRAULIC UNITS INSTALLED VALUABLE ADDITIONS TO COLLEGE EQUIPMENT The physical properties of all materials used in construction work can be tested on one or other of two hydraulic testing machines which are at present being installed in the materials laboratory of the School of Engineering at Canterbury University College. The machines, which were obtained through a substantial grant made to. the mechanical engineering department of the School of Engineering, are the on y ones of their kind in New Zealand and will bo a valuable addition to the teaching equipment of the school. They will supplement the work of the two materials-testing units installed in the laboratory 50 years ago, and will vastly increase the range of materials which can be tested and the accuracy of the tests. Because, of the large capacity of the machines it will be possible to extend the range of British and American

standard tests carried out in the laboratory. One of the machines can be used . for compression, tension and bending j tests on all types of metals and struc- ■ tural components, and can exert a total force of not less than 200.0001 b. i The unit ‘ has three load ranges— j O-IO.OOOIb by 101 b intervals. 0-50 0001 b I by 501 b intervals, and 0-200,000]b by J 2001 b intervals—and it has a guar-! anteed accuracy of 1-1 Cth of 1 per cent, throughout all the ranges. The rate of load increase can be varied from a few pounds a minute to! 200.0091 b a minute. The machine is fined with special equipment which makes it possible for a constant load to be maintained for an indefinite period of lime, irrespective of the amount of stretch in the material being tested. Loads can be applied at constantly increasing rates or in proportion to the rates at which the material is being stretched. It is also fitted with a high magnification electronic recorder enabling an exact picture to be drawn of the relationship between the stress and strain on the material. The machine was built bv the Baldwin Locomotive Works. Philadelphia, and it is re( ■ nised throughout the world as one of the finest testing machines in manufacture.

The other unit is of Swiss manufacture and is used for compression tests on materials such as concrete, brick and masonry. Its total load rance of 400,0001 b is twice that of the American un ; t. Eoth machines have twice the capacity and many refinements not developed when the older machines were installed in the laboratory 50 years ago. It is expected that the new machines will be ready for use by students when the second term begins next week. Professor R. J. Rastrick (Dean of the Faculty of Engineering at Canterbury University College) said yesterday that the pubTc would have an opportunity cf seeing the marh'nes in action at a laboratory ni?i‘ which it was proposed to hold later in the year.