How does paw pad of Canine attenuate ground impacts: a micromechanical finite element study
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Abstract
Background. Digitigraded mammals, e.g. dogs and cats, stand or walk on their digits or toes. Their paw pads beneath the digits or toes, rather than the entire sole of the foot, are in contact with the ground surface during locomotion. Digitigrades generally move more quickly and quietly than other animals. So far, little is known about the micro-scale structural characteristics of digitigrades' paw pads and its connection with the superior biomechanical functioning of their feet.
Methods. In this study, we investigated the micro-structure of the paw pad of German shepherd dog (GSD) using SEM and histological examination, and assessed the biomechanical functions of the micro-structured epidermis layer by using dynamic finite element (FE) simulations.
Results. We found that there exists a thick layer of stratified epithelium of a honeycomb like structure with conical protuberances (i.e. dermal papilla) embedded in each cell unit. Our FE simulation analyses revealed that this specially structured layer is capable of effectively attenuating the ground impact across a range of impact velocities. Moreover, this cushioning capacity becomes more pronounced with increased impact velocity. More importantly, this layer can also significantly reduce the mechanical stress transmitting to the soft dermal papillae and dermis by using an off-loading mechanism.
Discussion. This would provide more insights into the biomechanical functioning of the digitigrade's paw pads, and also facilitate the development of bio-inspired ground contacting components of robots and machines, and also the design of footwear and orthotics devices.
Cite this as
2016. How does paw pad of Canine attenuate ground impacts: a micromechanical finite element study. PeerJ Preprints 4:e2340v1 https://doi.org/10.7287/peerj.preprints.2340v1Author comment
This is a preprint submission to PeerJ Preprints.
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Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Huaibin Miao conceived and designed the experiments, performed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables.
Jun Fu conceived and designed the experiments, performed the experiments, analyzed the data, prepared figures and/or tables.
Zhihui Qian conceived and designed the experiments, contributed reagents/materials/analysis tools, reviewed drafts of the paper.
Luquan Ren contributed reagents/materials/analysis tools, reviewed drafts of the paper.
Lei Ren contributed reagents/materials/analysis tools, reviewed drafts of the paper.
Animal Ethics
The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):
1. The Institutional Review Board Committee of Jilin University
2. This study was conducted with the approval of the Institutional Review Board Committee of Jilin University, Changchun, P.R. China (NO. 20140418).
Data Deposition
The following information was supplied regarding data availability:
The raw data has been supplied as a supplementary file
Funding
This work was supported by the project of National Natural Science Foundation of China (No.51105167 & 51475202) The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.