Mechanical behaviour of Ostrich's eggshell at compression

Abstract

NEDOMOVÁ ŠÁRKA, BUCHAR JAROSLAV, STRNKOVÁ JANA: Mechanical behaviour of Ostrich's eggshell at compression. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 3, pp. 729-734 The deformation and fracture behaviour of Ostrich's eggs at the static compression has been investigated. The mechanical properties of egg to compression were determined in terms of average rupture force, specifi c deformation and rupture energy along X and Z axes. Exact description of the eggshell counter shape has been used for the verifi cation of a common accepted theory of the compression of bodies of convex form. The eggshell strength seems to be an unique function of the static stiff ness. The greatest amount of force required to break the eggs was required when eggs were loaded along the X axis and the least compression force was required along the Z axis. The specifi c deformation and rupture energy required for the eggs tested was lower along the X axis than the Z axis. The highest measure of fi rmness in the eggs tested was found to be along their X axis. Young's modulus of the elasticity, E, has been also evaluated. Its value is independent on the direction of the egg compression. The value of E is approximately two times higher that of the chicken eggs. strength, modulus of elasticity, eggshell stiff ness, rupture force

Some Physical, Morphological, and Mechanical Characteristics of Turkey (Meleagris gallopavo) Eggs

“…60-280.30 N mm -1 , depending on applied direction. Similar values were observed in Lohmann chicken eggs (124.64-133.02 N mm -1 ) by Altuntas & Sekeroglu (2008) and Hisex Brown chicken eggs (158.59-269.90 N mm -1 ) by Nedomova et al (2009), but much higher values were observed for ostrich eggs (932.50-1484.10 N mm 1 ) by Nedomova et al (2013). , respectively.…”

“…Nedomova et al (2014) also reported higher breaking strength in goose eggs (63.80-101.92 N) loaded at the same compression speed of 0.33 mm s -1 as in the present study. On the other hand, much higher breaking strengths are obtained in large eggs, such as ostrich eggs 531.52-904.54 N (Nedomova et al, 2013), whereas small eggs, such as those of Japanese quails (weighing 10.58-14.25 g) have much lower breaking strength, of 6.2-11.4 N (Polat et al, 2007). These results demonstrate the strong influence of egg weight on egg breaking strength.…”

Nature's technical ceramic: the avian eggshell

“…An average Young's modulus of 6.6 GPa was found for ostrich eggs, which is in high contradiction with the 100 GPa value obtained by Nedomová et al [26]. Nonetheless, the reported force -displacement curves for point load tests on ostrich eggs [26] were input into equation (3.7) and give a value of 6.5 GPa, which is remarkably close to the modulus calculated herein.…”

The Influence of Calcium Intake During the Period of Sexual Maturation of Pullets on its Retention and Eggshell Quality of Laying Hens

“…During the calcification they excretion in shells 2 to 3 g daily (Bar, 2009). The primary function of the shell is to protect the egg contents from external mechanical influences and microorganisms, which can affect the resulting quality and soundness of the eggs, or the hatchability of reproductive eggs (Nedomová et al, 2013). Shell quality is very important for eggs producers.…”