Fig. 1

Establishment of fluid-solid coupling model and boundary conditions. A. Micro-CT image of rat femur in control group, B. Cancellous bone model in the marked area of Fig. 1A initially established by Mimics software, C. Cancellous bone model optimized by Geomagic Studio software, D. Finite element models of cancellous bone in the marked area of Fig. 1A and the black wireframe in Fig. 1C, E. Boundary conditions applied to cancellous bone and fluid models. The black arrows represent displacement loading, the red arrows show fluid pressure, the green arrows indicate elastic foundation, and the black arrow heads denote fixed constraint