Verify IELSM–Q4 coupling

Verify the numerical performance of coupling Isotropic Elastic Lattice Spring Model (IELSM) elements with four-node isoparametric (Q4) finite elements through direct node sharing.

Background

The paper establishes that IELSM elements can be directly coupled with constant-strain triangular (CST) and Q4 finite elements through shared nodes because their boundary displacement interpolation is compatible along straight edges. Numerical examples, however, use only IELSM–CST coupling. The numerical behavior of the IELSM–Q4 combination, including its accuracy and interface performance, is therefore unresolved in the paper.

References

The compatibility of IELSM and Q4 elements through node sharing follows from the same boundary-interpolation argument, while its numerical verification is left for future work.

— Tessellated Isotropic Elastic Lattice Spring Model for Quasi-Brittle Fracture  (2609.28970 - Li et al., 24 Sep 2026) in Section 3.2, Hybrid Assembly Strategy for IELSM and Finite Elements