A Moment-of-Inertia-Dependent Surface Homogenization Method for Porous Polymer Beams.

Area of Science:

• Materials Science
• Mechanical Engineering
• Nanotechnology

Background:

• Porous polymer beams exhibit size-dependent bending, especially at the nanoscale.
• The link between this size dependency and microstructure is not well understood.
• Existing methods like direct simulations are computationally intensive, and classical multiscale methods lack surface effect considerations.

Purpose of the Study:

• To develop an equivalent model for porous polymer beams that accounts for surface effects on bending.
• To establish an efficient prediction framework for size-dependent bending responses.
• To investigate the moment-of-inertia-dependent surface mechanism influencing metamaterial beam behavior.

Main Methods:

• Developed an equivalent model incorporating surface-driven moment of inertia, surface strength, and surface thickness.
• Introduced a surface homogenization method to capture size-dependent Young's modulus.
• Created an online prediction framework using an offline dataset from the new homogenization method.

Main Results:

• The proposed surface homogenization method achieved relative errors below 4%, a significant improvement over classical methods (up to 1108% error).
• Computational cost was substantially reduced compared to direct numerical simulations.
• The study identified the moment-of-inertia-dependent surface mechanism as key to size-dependent behavior.

Conclusions:

• The novel surface homogenization method accurately predicts the size-dependent bending of porous polymer beams.
• The developed framework offers an efficient and accurate tool for metamaterial beam design and performance prediction.
• This research clarifies the surface-driven mechanisms governing nanoscale material behavior.