Competition between cracking and peeling in composites: a simulation in 2-d

• Published in: Journal of materials science Vol. 49; no. 21; pp. 7507 - 7512
• Main Authors: Dutta, Tapati, Tarafdar, S.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.11.2014; Springer; Springer Nature B.V
• Subjects: Adhesive strength; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Coating; Coatings; Cohesion; Composite materials industry; Constituents; Crystallography and Scattering Methods; Degeneration; Dependence; Elastic properties; Failure mechanisms; Materials Science; Parameters; Peeling; Polymer Sciences; Simulation; Solid Mechanics; Substrates; System Relaxation; Substrate Adhesion; Desiccation Crack; Desiccation Rate; Type Node
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8456-0

When a material coating is left to dry on a substrate, cracking and peeling may set in which leads to the ultimate degeneration of the coating. Parameters like the elastic properties of the constituents of the coating, desiccation rate, role of substrate and the volume fraction of the constituent components of the coating affect the failure mechanism. We simulate desiccation of a 2-D vertical section of a layer of a two component (A,B) composite on a substrate to study the dependence of cracking and peeling on these parameters. For a given composite and substrate, it is observed that cracking or peeling depends only on the percentage of the constituents present in the composite. In our simulation, p is the volume fraction of the constituent having greater cohesion (B). The characteristic time of complete failure t crack is found to increase linearly with decrease in desiccation rate. This rate of increase in t crack is the highest for peeling and least for horizontal cracking. When adhesion between substrate and layer is stronger than the cohesion (BB) and adhesion (AB) of the constituents of the composite, peeling is least favoured. Failure by horizontal cracking gives way to vertical cracking as the percentage of the stronger component (B) increases. If adhesion between substrate and layer is weaker than that between the constituent components of the composite, peeling is dominant. Mechanical strength is found to be always greater for a composite than a pure material. If one component has low cohesive strength (AA), the strength of the composite can be greatly increased if the other component (B) is chosen such that adhesion (AB) becomes comparable to cohesion (BB). For certain combinations of the components, the composite is found to completely resist failure.