Coupled Simulation of Deformable Bodies and ISPH Fluids for Secondary Bone Healing Nadine Abu Rumman 1,2 , Patric Müller 1 , Prapanch Nair 1 and Thorsten Pöschel 1 1 Institute for Multiscale Simulation, Friedrich-Alexander University Erlangen-Nürnberg, Germany 2 Toulouse Institute of Computer Science Research, Paul Sabatier University, France Figure 1: Top row: deformation rate; an animated sequence of increasing levels in strain deformation ranging from 0.000 to 1.370. Bottom row: flux velocity; an animated sequence that illustrates a fluid particles’ velocity during the soft tissues deformation, and shows the diffusion of the fluids within the tissues. In the secondary bone healing process, this flux allows nutrient transportation through cartilages, which influences the healing process significantly. Abstract We propose a new scheme for the two-way coupling of incompressible fluids and deformable bodies, where we focus on a medical application; in particular, secondary bone healing. Our method allows for accurate simulation and visualisation of the secondary bone healing process, which is used to optimise clinical treatment of bone fractures. In our simulation, the soft tissues are simulated as elastic materials using Strain Based Dynamics (SBD), and fluid is simulated using Incompressible Smoothed Particle Hydrodynamics (ISPH). The interaction model we propose works with any type of deformation technique as long as the object surface is represented by a polygonal mesh and the fluid by Lagrangian particles. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Animation and Virtual Reality 1. Introduction Simulation of the physical interaction between fluid and de- formable bodies is of great importance to numerous applications in science, engineering, and medicine. However, producing simul- taneously the elastic behaviour of the deformable body and fluid phenomena can be complex and computationally demanding. In the present work, we study this problem for a medical application. In particular, we present a new simple yet stable method for sim- ulating the interaction between elastic material and fluid in sec- ondary bone healing process. The goal of the simulation itself is to investigate the mechanical stimuli driving tissue development dur- ing secondary bone healing to optimise clinical treatment of bone fractures. The materials used by the body to repair the fracture via secondary healing are bone, cartilage and soft tissue. The cellular structure of the soft tissues is made of an interconnected network of solid struts or plates, which form the cell’s edges and faces. To adapt the tissue’s material properties, it is simulated as non-linear elastic materials using Strain Based Dynamics (SBD) [MCKM14]. The cellular materials of the tissues are modelled as permeable to fluid flow, while fluid is allowed to occur across borders of the model to imitate the continuity of the callus (Fig. 1). Mechani- cal stimuli produce relatively small pore pressures on the tissue, which cause shear deformation, as well as volumetric deformation, which is expected to increase fluid flows in the fracture site. Fluid is simulated using Incompressible Smoothed Particle Hydrodynamics c  2017 The Author(s) Eurographics Proceedings c  2017 The Eurographics Association. EUROGRAPHICS 2017/ P. Benard and D. Sykora Poster DOI: 10.2312/egp.20171036