Failure in composites and coatings

High-performance composites and coatings rely on the integrity of their materials and the bonds between them. Cracking and interface separation can reduce structural stiffness or compromise a protective layer, even before damage becomes visible. Understanding how failure develops is essential for choosing materials and designing durable components.

These failure mechanisms are particularly relevant to:

• Automotive: high-performance coatings protect component surfaces under demanding contact conditions. Cracking or loss of adhesion can compromise that protection. Modelling these failures helps assess coating durability and compare material choices.
• Aerospace: lightweight composites help reduce aircraft weight, but cracking and separation between layers can compromise structural strength. Understanding how this damage develops supports safer, damage-tolerant designs.

At Mesh-Oriented Solutions, we are developing simulation tools in MoFEM to model progressive fracture alongside contact. Our mixed formulation treats stress as an independent unknown field, providing a direct description of the forces transmitted across interfaces. An energy-based cohesive model relates these forces to the opening and sliding of neighbouring surfaces, capturing how their bonds weaken as damage accumulates.

Key capabilities include:

• Combined opening and sliding at interfaces under complex loading
• Irreversible damage, retaining the effects of previous loading
• Crack-face contact, allowing damaged surfaces to close without restoring their original bond
• Material-specific calibration using interface stiffness, strength and fracture energy

Composite interface fracture

The first demonstration shows how cracks develop and interfaces separate in a composite under tension. Tracking this interaction helps identify vulnerable regions and assess the influence of interface bonding on overall failure.

Indentation-driven fracture

The second demonstration illustrates a rounded tool pressing into a brittle surface layer. This contact-driven example highlights the cracking mechanisms relevant to coating damage under localised loading.

These tools support material selection and design assessment: comparing bonding strategies, exploring resistance to localised damage and focusing physical testing on the most promising designs.