Compliant threads maximize spider silk connection strength and toughness.

Area of Science:

• Biomimetics and Bio-inspired Engineering
• Materials Science and Mechanics
• Structural Biology

Background:

• Spider webs demonstrate remarkable material efficiency and diverse functionalities, evolved over millions of years.
• Silk-on-silk fiber junctions within spider webs are crucial structural components that have been under-investigated from a mechanics perspective.

Purpose of the Study:

• To conduct a theoretical and computational analysis of idealized silk-on-silk fiber junctions.
• To investigate the impact of anchor thread rigidity on the mechanical performance of these junctions.

Main Methods:

• Modified the theory of multiple peeling to analyze fiber junction performance.
• Systematically varied anchor thread rigidity by scaling stress-strain response and introducing pre-strain.
• Employed theoretical modeling and computational analysis.

Main Results:

• Increased extensibility (compliance) of the anchor thread enhances the toughness and strength of the silk-on-silk connection.
• Compliant anchorages dramatically increase effective adhesion strength compared to rigid substrates.
• This enhancement is attributed to nonlinear alignment (contact peeling angle) between the thread and anchor.

Conclusions:

• Compliance in anchorages is a key design principle for robust fiber-to-fiber connections.
• Findings can inform novel engineering designs for load transfer in compliant fiber-to-fiber systems, including bio-inspired materials.
• The study highlights the structural advantages of flexible anchorages in natural and engineered systems.