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Title: Viscoelastic properties of the equine hoof wall
The equine hoof wall has outstanding impact resistance, which enables high-velocity gallop over hard terrain with minimum damage. To better understand its viscoelastic behavior, complex moduli were de- termined using two complementary techniques: conventional ( ∼5 mm length scale) and nano ( ∼1 μm length scale) dynamic mechanical analysis (DMA). The evolution of their magnitudes was measured for two hydration conditions: fully hydrated and ambient. The storage modulus of the ambient hoof wall was approximately 400 MPa in macro-scale experiments, decreasing to ∼250 MPa with hydration. In contrast, the loss tangent decreased for both hydrated ( ∼0.1–0.07) and ambient ( ∼0.04–0.01) conditions, over the frequency range of 1–10 Hz. Nano-DMA indentation tests conducted up to 200 Hz showed little frequency dependence beyond 10 Hz. The loss tangent of tubular regions showed more hydration sensitivity than in intertubular regions, but no significant difference in storage modulus was observed. Loss tangent and effective stiffness were higher in indentations for both hydration levels. This behavior is attributed to the hoof wall’s hierarchical structure, which has porosity, functionally graded aspects, and material interfaces that are not captured at the scale of indentation. The hoof wall’s viscoelasticity characterized in this work has implications for the design of bioinspired impact-resistant materials and structures.  more » « less
Award ID(s):
1926353
PAR ID:
10537688
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Elsevier
Date Published:
Journal Name:
Acta Biomaterialia
Volume:
184
Issue:
C
ISSN:
1742-7061
Page Range / eLocation ID:
264 to 272
Subject(s) / Keyword(s):
Hoof wall Viscoelasticity Dynamic mechanical analysis Biological material Nanoindentation Impact resistance
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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