Discussion: “A Direct-Stress Analysis of Orthotropic Cantilever Plates” (Coull, A., 1965, ASME J. Appl. Mech., 32, pp. 67–70)

Abstract

discussion these members at 75 min. The error ill the predicted deformations at 75 min by this theory ranged from 100 to 400 percent. It is the writer's opinion that theories based on equation (4) deserve considerable consideration. The theory is equally valid for members made of plastics or metals (at elevated temperature). Multiaxial creep theories based on equation (4) can be derived with reasonable ease. The resulting theories are independent of the properties of the material so that design curves can be constructed for a given load-carrying member. The theory is no more complex for members subjected to variable loads than for constant loads. In case of variable loading, the creep properties are required for tension and compression specimens subjected to the same load history as the member to be designed. The magnitudes of <ro and to at any specified time would include the effect of load history up to that time. Test data [1, 2, 5, 6, 7] have confirmed the validity of this statement for loads increasing in magnitude and for a decrease in load of 15 to 40 percent but have not been confirmed for alternating loading.