The size effect in adhesive contact on a gradient nanostructured coating.

Area of Science:

• Materials Science
• Mechanical Engineering
• Nanotechnology

Background:

• Adhesive contact mechanics are crucial for understanding the performance of nanostructured materials.
• Gradient Nanostructured (GNS) coatings exhibit unique size-dependent properties relevant to advanced applications.
• Previous models often simplify material gradients, necessitating a more detailed analysis.

Purpose of the Study:

• To investigate the adhesive contact problem of a rigid cylindrical punch on a GNS coating.
• To analyze the influence of size effects and material gradients on the coating's mechanical behavior.
• To provide insights for optimizing GNS coatings in nanoelectromechanical systems (NEMS).

Main Methods:

• Application of the laminated plate model for GNS coating characterization.
• Utilizing plane strain couple stress elasticity to describe material behavior.
• Employing Fourier integral transform and transfer matrix methods to derive governing equations.
• Numerical calculation of results to analyze various parameters.

Main Results:

• The characteristic material length, adhesion parameter, and non-homogeneity significantly affect the mechanical response.
• Shear modulus variation with depth (exponential or power-law) impacts nanoscale contact behavior.
• Size effects play a critical role in the adhesive contact mechanics of GNS coatings.

Conclusions:

• The study provides a framework for understanding adhesive contact in GNS coatings under size-dependent elasticity.
• Adjusting the gradient index of GNS coatings can mitigate contact deformation and damage.
• Findings offer a pathway to enhance the reliability and performance of NEMS devices.