The Effect of Deformation Rate and Other Factors on the Force Required to Fracture Egg Shells in Measuring Shell Strength

Abstract

The measurment of egg shell strength by quasi-static instrumental techniques is empirical so that the test conditions must be controlled to obtain comparable data. Factors that influence egg shell strength measurements were examined and include the effects of: a) the response of the force recording equipment, b) the rate of deforming the egg, which is exponential, c) perturbations in the force-deformation relations, d) the mechanical details of the test instrument, e) the temperature, humidity and age of the egg when the measurement is taken, and f) other yet unknown factors. At present, all the factors that affect quasi-static shell strength measurements are not fully understood. Thus, it is too soon to establish standard test procedures for universal application. Until the mechanical techniques presently used to measure egg shell strength can be standardized, details of the methods applied, the equipment used and its accuracy under the test conditions should be described when shell strength data are reported.