..., where the baleen meets the tongue (although the lateral baleen is thicker, with a wider region of flat cortical keratin). Variation in tubular size and density may explain why plates flex more readily on lateral (relative to medial) sides in manual axial flexion tests. Preliminary evaluation of baleen...

... (Young's modulus, E ) of the material (keratin) and the geometry of the rachises, more precisely the second moment of area ( I ). Two independent methods were employed to determine Young's modulus of feather rachis keratin. Moreover, the second moment of area and the bending stiffness of feather shafts...

...B. W. Li; H. P. Zhao; X. Q. Feng; W. W. Guo; S. C. Shan SUMMARY Bovine horn is composed of a sheath of keratin overlying a bony core. Previous studies of the bovine horn sheath have focused mainly on its morphology and compositions. In the present paper, we performed a series of uniaxial tension...

... along the longitudinal axis. Microscale tests conducted on rows of keratin strands from the inner wall tubules and intertubular material, and on intertubular keratin strands of the mid-wall, produced estimates of the stiffnesses of the hydrated matrix (0.03 GPa) and intermediate filament (IF; 3–4 GPa...

... while the birds flew at a slow speed (approximately 5–6 m s −1 ) were used to calculate functional stresses on the basis of published values for the elastic modulus of feather keratin. These stresses were then compared with measurements of the failure stress obtained from four-point bending tests...

... of peak compressive strains do not correlate strongly with microstructural axes in the material. Comparison of our in vivo strain records with previous in vitro studies of the material properties of the wall shows that hoof keratin behaves as a multidirectional composite, capable of tolerating its usual...

...J. E. A. Bertram; J. M. Gosline ABSTRACT Tensile moduli and J-integral fracture toughness values were determined for horse hoof-wall keratin at four hydration levels. The stiffness of hoof-wall was influenced by water content to a greater degree than is the stiffness of other mammalian hard...

...J. E. A. Bertram; J. M. Gosline ABSTRACT An engineering fracture mechanics approach was applied to the analysis of the fracture resistance of equine hoof-wall. The relationship between fracture toughness and the morphological organization of the keratin hoof tissue was investigated. Fracture...