"A review of the literature pertaining to the subject is presented. Many series or impacts were made on specimens of gypsum which were already under a static load. A special. repetitive impact machine was used to allow a variety or weights to fall from predetermined heights. Tests were conducted inside a roan constructed especially for these tests. Heat gained or lost through the ceiling and walls was kept at a minilI1um by a lining or aluminum-covered, fiber glass insulation. Temperature and humidity conditions were kept nearly constant by a combination air-conditioner and dehumidifier.
Repetitive loading of the prestressed specimen was round to have many similarities to that or static loads alone. There is an equivalent to primary and secondary creep and a creep recovery after the repetitive impact has stopped. Results are not entirely predictable; many major and minor trends occur within the overall trend.
The occurrence of an equivalent primary creep seems to depend upon the previous dynamic loading and may appear if' the energy of the falling weight exceeds the maximum energy of the weight used previously.
A new phenomenon is described and given the term 'Creep Coasting.' This is the additional deformation which occurs after the completion of a prolonged series of impacts on a specimen which is under a static load applied in the same direction as the dynamic load. This phenomenon could easily have been overlooked had it not been for the high sensitivity of the multiple speed continuous recorder"--Abstract, p. ii
George Bromley Clark
Robert F. Bruzewski
George E. Vaughan
John A. Nelson
M.S. in Mining Engineering
Missouri School of Mines and Metallurgy
x, 113 pages
© 1963 Arthur Joe Bush, All rights reserved.
Thesis - Open Access
Print OCLC #
Bush, Arthur Joe, "Some effects of impact of low magnitude on the deformation of prestressed gypsum cylinders." (1963). Masters Theses. 2870.