Microscale Yarn Stress Distribution Mechanism in Sheared Kevlar Plain-Woven Fabrics Revealed by Micro-Raman Spectroscopy

Kevlar plain-woven fabrics serve as core materials for lightweight ballistic protection, yet their microscale yarn stress evolution under in-plane shear cannot be quantitatively captured by macroscopic testing methods. This work employs static micro-Raman spectroscopy to characterize the internal stress distribution of sheared aramid textiles. A linear Raman shift–stress correlation is first established through single-yarn tensile calibration. The fabric specimen is loaded to a fixed shear angle of 30° using a picture-frame rig, after which the fixture is fully locked for undisturbed static Raman scanning. Full-field mapping results show obvious stress concentration at yarn crossover regions, with low-stress zones formed at inter-yarn gaps. The heterogeneous stress field is dominated by yarn rotation, geometric confinement and inter-yarn interfacial friction. This research provides direct mesoscale experimental data to interpret shear-induced stress redistribution and verifies the capability of micro-Raman spectroscopy for textile micromechanics characterization.