Variation of Young's modulus with the test specimen's aspect ratio.

A study of Young's modulus in flexure of a number of methacrylate polymers indicated that the results were dependent on the test specimen thickness. The Young's modulus calculated from simple bending theory decreased with increased specimen thickness. This effect could not be accounted for either by the usual corrections for shear or corrections for the effect of the width/length ratio. It transpires that the effects noted experimentally are due to the combined effects of shear and the width/length ratio.