Dimensioning of dog bone specimens and numerical analysis of the effects of different fillet radii, clamp area and pinhole loading on the stresses in such specimens

The effects of different fillet radii, clamp area dimensions, and pinhole loading through a hole located in the clamp area of a dog bone specimen were investigated using the Finite Element Analysis (FEA) software Abaqus. Changes in the fillet radius were shown to have little effect on the distribution and magnitude of the von Mises stresses. Different dimensions of the clamp section gave different von Mises stress distributions within the clamp section, with the maximum values remaining within the gauge section, thus implying that limitations of available cutters and material could be accommodated by varying the dimensions of test specimens. Introduction of pinhole loading in order to minimise torsion, led to a shift of the maximum von Mises stress from the gauge section to the edge of the pinhole, an indication that the benefits of minimising torsion required to be weighed carefully. The observed shift was only significant however, for failure load levels and for cyclic loading. A set percentage change rather than the absolute convergence of the von Mises stresses was shown to be a more economical way of arriving at an optimal mesh density, a characteristic that was seen to vary from one location to another. African Journal of Science and Technology Vol. 5(2) 2004: 60-72