Bhattacharya, DebayanDebayanBhattacharyaPrashant, AmitAmitPrashant2025-08-312025-08-312019-01-01[9780784482124]10.1061/9780784482124.0012-s2.0-85063536416https://repository.iitgn.ac.in/handle/IITG2025/23394The sudden loss in load carrying capacity of a soil specimen from its homogeneous material response is coined as the onset of instability or bifurcation in geomaterials. A numerical investigation of the coupled undrained (globally undrained, locally drained) transient analysis in Hostun RF sand under biaxial loading has been carried out in ABAQUS along with the implementation of a user defined generalized 3D nonassociative material model. Onset of localization has been probed by inducing material heterogeneity within the numerical framework. This requires a mesh convergence study for a given perturbation intensity. Numerically predicted instability onset strain becomes practically asymptotic to the theoretically predicted value with mesh refinement. The simulations revealed -that increased intensity of material heterogeneity induced in the sand specimens significantly reduced the bifurcation onset strain.en-USfalseConference Paper1-10201901