Arctic sea ice is changing rapidly, increasing the need for predictive, mechanics-informed simulation tools that resolve deformation, contact and fracture across interacting floes. We present a combined finite-discrete element method (FDEM) code developed by Tanuki Technologies and deployed for mesoscale simulation of sea-ice dynamics in collaboration with University College London (UCL), the University of Cambridge, the University of Manchester, the University of Washington, and industrial partners. Sea-ice sheets are discretised into triangular elements that act simultaneously as (i) discrete bodies, enabling multi-body kinematics and robust normal and frictional contact between floes, and (ii) finite elements, resolving in-plane deformation and stress evolution within each floe. Cohesive interfaces between neighbouring elements capture damage initiation and fragmentation. Once cohesion fails, fragments transition to independent bodies that translate, rotate, collide, and re-contact, reproducing the coupled breakup--interaction processes that underpin ridging, lead formation, and floe-size evolution. The framework leverages the tanuki™ toolset for parallel high-performance computing, enabling large-domain simulations while retaining rapid prototyping and extensibility. It incorporates key cryosphere forcings and heterogeneity, including spatially varying strength and elastic moduli driven by interventions (e.g. artificial thickening), body forces representing wind drag and ocean currents, and optional parametrisations for ridging. The talk will describe the modelling approach and discuss simulation capabilities and outlook for (i) exploring environmental drivers and intervention strategies relevant to Arctic ice-loss mitigation, and (ii) coupling mesoscale mechanics with larger-scale sea-ice models.