A Study of the Effect of Repeated Tension Impact Loads Upon Certain Metals Used in Aircraft Construction

Citation

Beardsley, George Francis and Coates, Leonidas Dixon (1939) A Study of the Effect of Repeated Tension Impact Loads Upon Certain Metals Used in Aircraft Construction. Master's thesis, California Institute of Technology. doi:10.7907/R4GM-7G81. https://resolver.caltech.edu/CaltechETD:etd-01102006-132339

Abstract

A test method is developed for evaluating the Impact Endurance Limit of a material. The Impact Endurance Limit is defined as the energy per blow in tensile impact loading below which the specimen will withstand an indefinitely large number of blows without rupture, and this value is given for ALCOA 24ST and 14ST, with and across the grain, and Dowmetals X and Z-1 with the grain. Evidence is presented that this value probably does not depend directly either on the energy absorbed in breaking in one blow or on the brittleness of the material. The ability to absorb energy in failure under static loading is shown to decrease nearly linearly with dynamic strain, while the ability to carry design static load is not adversely affected by any amount of dynamic strain short of failure. Some shortcomings of the present test methods are pointed out and a new machine is briefly described which will be used in further investigation of repeated tension impact. Co-author: L.D. Coates

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