Consistency of simulated stress distribution with experimental mechanoluminescent intensity distribution facilitating stress visualization device design

Abstract

Mechanoluminescent (ML) materials emit light in response to dynamic stress variations, making them promising candidates for applications in structural health monitoring. The development of mathematical models to predict spatial stress distributions and clarify the relationship between stress and luminescence intensity is essential for optimizing the practical use of ML materials. In this study, we established mathematical models. We performed numerical simulations to determine stress magnitudes and distributions along path points in cylindrical samples, both with and without a notch, under varying normal force loads (1000–5000 N). Experimental compression tests were conducted on ML cylinders fabricated from a composite consisting of ZnS: Cu²⁺, CaZnOS: Mn²⁺, and CaZnOS: Mn²⁺, Bi³⁺ fluorescent powders embedded in epoxy resin. Luminescence intensity distributions along the path points of the notched and unnotched samples (2 mm wide and deep notches) were analyzed. The findings demonstrate a strong correlation between the simulated stress distributions and the experimentally observed luminescence intensity patterns. This approach provides a reliable framework for designing ML devices using numerical simulations, applicable to a wide range of ML materials with varying geometries or damage conditions.