A new thermomechanical coupled FDEM model for geomaterials considering continuum-discontinuum transitions

Abstract

A new thermomechanical (TM) coupled finite-discrete element method (FDEM) model, incorporating heat conduction, thermal cracking, and contact heat transfer, has been proposed for both continuous and discontinuous geomaterials. This model incorporates a heat conduction model that can accurately calculate the thermal field in continuous–discontinuous transition processes within a finite element framework. A modified contact heat transfer model is also included, which accounts for the entire contact area of discrete bodies. To align with the finite strain theory utilized in the FDEM mechanics module, the TM coupling module in the model is based on the multiplicative decomposition of the deformation gradient. The proposed model has been applied to various scenarios, including heat conduction in both continuous and discontinuous media during transient states, thermal-induced strain and stress, and thermal cracking conditions. The thermal field calculation model and the TM coupling model have been validated by comparing the numerical results with experiment findings and analytical solutions. These numerical cases demonstrate the reliability of the proposed model convincingly, making it suitable for use across a wide range of continuous and discontinuous media.