How does the canine paw pad attenuate ground impacts? A multi-layer cushion system

Area of Science:

• Biomechanics
• Materials Science
• Robotics

Background:

• Previous studies focused on macroscopic properties of digitigrade paw pads.
• Micro-scale structural characteristics and their relation to cushioning remain underexplored.

Purpose of the Study:

• To investigate the micro-scale structural characteristics of digitigrade paw pads.
• To understand the relationship between these structures and the pads' exceptional cushioning.
• To elucidate the biomechanical functioning of digitigrade paw pads.

Main Methods:

• Finite element analyses were employed to model the paw pad structure.
• Simulations covered impact velocities ranging from 0.05 to 0.4 m/s.

Main Results:

• The epidermis layer effectively attenuated ground impact and uniformly distributed von Mises stresses.
• The dermis and subcutaneous layers function as a hydrostatic system for energy storage, release, and dissipation.
• All three layers collaborate to meet biomechanical demands of locomotion.

Conclusions:

• The multi-layered structure of digitigrade paw pads is key to their cushioning and biomechanical function.
• Findings can inform the development of bio-inspired components for robots and footwear design.