Role of Particle Shape in the Combined Fabric Evolution for Contact Normal and Particle Orientation Anisotropy Based on X-Ray Tomography Imaging

Particle shape plays a crucial role in influencing the mechanical behavior of granular materials, yet its evolution under loading requires further understanding. This study validates the combined fabric evolution (CFE) equation by simulating both particle orientation and contact normal fabric evolutions of real granular materials with different shapes using X-ray computed tomography (CT) aided triaxial compression tests and quantitatively evaluates the role of particle shape in fabric evolution. The triaxial tests show that particle shape has significant influence on the macro- and micro-scale behavior of granular materials. The particle orientation and contact normal fabric evolution for four different granular materials with different particle shapes are successfully simulated using the CFE equation, highlighting the importance of considering the interaction between the two different fabric tensors. Strong linear correlations are identified between CFE equation parameters and particle shape descriptors including aspect ratio, sphericity, Wadell roundness, and overall regularity. Particularly, Wadell roundness is most strongly correlated with all CFE parameters and allows for stable fabric evolution simulation using CFE within a wide value range.