Speaker
Description
Coupled multibody-finite element (MB-FE) simulations are state-of-the-art when characterizing a system's global dynamic behavior as well as local stress and strain phenomena due to deformation. In biomechanical research, this approach can address different hierarchical levels, including cellular, tissue, or organ system levels. Artisynth is an open-source Java-based biomechanical simulation framework for co-simulating multibody and finite element models with forward and inverse simulation capabilities. It therefore has huge potential in future biomechanical research. Despite its ability to import and edit OpenSim models directly, a fully functional Artisynth model of the lower limb that can be readily extended by finite element structures to study gait is missing up to this day. Here, we present the current state of our multibody model of the lower limb, which is based on OpenSim’s Gait2392 model. The model produces physiologically reasonable joint angles during gait for a given set of experimental marker trajectories and calculates promising joint moments and muscle forces when compared to simulations of the same model and motion in OpenSim 4.5. Experimentally measured ground reaction forces are applied directly to the foot segment of the model, as performed in OpenSim 4.5. Calculated angles for right hip adduction, flexion, and rotation reach from -10.3° to 3.2°, -22.8° to 25.2° and -9.1° to 0.5°, whereas corresponding angles in OpenSim span -7.7° to 6.9°, -21.9° to 22.1° and -11.1° to 7.5°. For the left, our angles are -8.5° to 4.2°, -20.8° to 25.1° and -11.3° to 3.0° vs. -7.9° to 5.5°, -22.6° to 21.7° and -10.3° to 6.5°. Our right knee angles range from -69.5° to -0.2° vs. -69.8° to 1.0° in OpenSim, whereas corresponding left angles are -69.8° to -0.1° and -70.7° to 0.1° in OpenSim, respectively. Finally, calculated right ankle angles cover -17.4° to 11.5°, whereas they are -8.8° to 16.0° in OpenSim. For the left, the ankle angles are -18.1° to 11.5° vs. -9.7° to 14.3° in OpenSim. This model can serve as a foundation for coupled MB-FE simulations that we intend to extend in our future research. Yet the principle is also transferable to biomechanical research in adjacent fields, where research can be accelerated using already existing OpenSim models.
