Analysis of bioinspired non-interlocking geometrically patterned interfaces under predominant mode I loading

Area of Science:

• Materials Science and Engineering
• Fracture Mechanics
• Biomimetics and Natural Design

Background:

• Geometrically patterned interfaces are prevalent in nature, contributing to enhanced material properties.
• Geometry significantly influences material strength, toughness, and damage tolerance across various species.
• Understanding crack propagation mechanisms at interfaces is crucial for designing robust materials.

Purpose of the Study:

• To investigate the role of crack opening shape behind the crack tip during interface crack propagation.
• To analyze how amplitude-to-wavelength aspect ratios of patterned interfaces affect crack behavior.
• To explore the influence of material length scale on geometrical toughening effects.

Main Methods:

• Employed two analytical models to study crack opening shapes for varying aspect ratios.
• Utilized finite element simulations and the J-integral method for quantitative analysis.
• Applied a finite element-based cohesive zone model to examine material length scale effects.

Main Results:

• Geometrical toughening is demonstrated to be influenced by a size effect.
• The toughening effect was found to be bounded, existing between two limiting conditions.
• The relationship between geometrical characteristics and emergent material length scale was elucidated.

Conclusions:

• The shape of the crack opening behind the crack tip plays a critical role in interface toughness.
• Material length scale interacts with geometrical features, modulating toughening mechanisms.
• Geometrical toughening is a size-dependent phenomenon with inherent upper and lower bounds.