Quantitative fracture characterization and damage evolution mechanisms of MWM under splitting tension

• Developed sustainable MWM composite: MOC matrix with 20 % straw/sawdust. • Novel piecewise constitutive model for MWM: 6th-polynomial ( R ²=0.942) ascent & rational fraction ( R ²=0.999) descent. • Damage Degree Factor quantifies 3-stage evolution: elastic (<37.90 % P max ), progressive damage (43.07 %∼78.92 % P max ), failure (>83.11 % P max ). • Angles of fracture trace lines in MWM splitting obey Gaussian distributions ( R ²>0.9). • Integrated framework (DIC + FracPaQ + DDF) enables damage assessment of sustainable composites. This study establishes a quantitative framework for fracture characterization of magnesium-based wood-like material (MWM) under splitting tension, addressing critical gaps in damage evolution modeling and crack morphology quantification. Through integrated digital image correlation (DIC) and cubic specimen (100 mm × 100 mm × 100 mm) testing, a piecewise constitutive model was developed, combining a 6th-degree polynomial (ascending phase, R 2 =0.942) with a rational fraction function (descending phase, R 2 =0.999), resolving limitations of linear approximations. A novel Damage Degree Factor (DDF) derived from full-field strain variations quantifies three-stage damage progression: elastic dominance, progressive damage accumulation, and failure stage. Statistical morphology analysis via FracPaQ reveals angles of fracture trace lines follow Gaussian distributions ( R 2 >0.9), evolving from vertical dominance to increased horizontal components due to crack widening and secondary cracking. These findings provide a mechanistic basis for structural safety evaluation of sustainable low-carbon composites.