Gardner impact test

Lavach [50] discussed the factors that affect results obtained by the Gardner impact test. This test is used by plastics producers to approximate the mean failnre energy for many plastics. The test is inexpensive and easy to operate. The test eqnipment can be placed close to the manufacturing equipment, permitting fast and nearly online determination of the impact resistance of an article. The test is useful for finding the mean failure energy for brittle thermoplastics such as acrylic and high-impact polystyrene with standard deviations between 8% and 10%. 

The sharpness of a notch is well known to have a strong influence on the impact performance of notched specimens. The extent of this effect is found to vary considerably from polymer to polymer. 

As mentioned above, a low Izod valne gives a warning regarding the care that should be exercised in design to remove points of stress concentration if optimum impact behavior is to be obtained with a component in practice. It was also mentioned that a more reliable measure of notch sensitivity can be obtained by carrying out tests using a series of notch radii rather than a single standard notch. 

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The authors are grateful to Himont, Inc. for a fellowship to H.K.A., support from 3M Co. for hardware and software development, and to Mr. George Turner of Turner Designs, Inc., for loan of a Luminometer. The assistance of Mr. Burt Blanch with the Gardner impact tests is gratefully acknowledged. 

Impact resistance of epoxy coatings, as determined by a reverse Gardner impact test, is enhanced by liquid polymer addition independent of functional type. Again, these results are consistent with both unpigmented and pigmented model coatings. Although... 

The method detailed in ASTM D.S420 [87] is somewhat unusual compared to other impact standards in that the test piece, which is placed on a support plate having a circular hole of given size, has a striker resting upon it. and the striker is then impacted by the falling weight. This is the so-called Gardner impact test, and a number of variations in... 

Gardner Impact Test (falling-weight test) A test for the impact resistance of rigid plastic sheets or parts. ASTM... 

Mackin, T. J., A Comparison of Instrumented Impact Testing and Gardner Impact Testing, Instron Corp., Canton, MA. 

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