Biomechanical 3D-Muscle Modeling and Validation

Within this project, researchers from the Fraunhofer IPA are developing novel 3D computational skeletal muscle models to predict the motion of an arm upon the stimulation of skeletal muscles. Moreover, the IPA investigates novel experimental evaluation techniques for ergonomic questions arising in the manufacturing and automotive industry.

The overall goal is to accurately model the actual assembling procedure implemented within the company. For this purpose, the setup is rebuilt in the lab. To acquire and quantify loading conditions of an employee during particular movements, the body’s motion, the muscle activations and the joint moments and forces are measured. The resulting data are not only used to validate the simulations of the 3-d skeletal muscle models but also for the multi-body simulations.

The constitutive model for describing the muscle-tendon-complex in 3D follows an phenomenological approach enabling the motion of extremities by activating the respective muscles. One example is the motion of the lower arm. To determine the most effective combination of muscle activations within our six-muscle-arm, response surfaces are computed for the individual muscles. These response surfaces allow also fast predictions and the use of such models within optimization, e.g. minimizing a given object function. Extending the muscle’s constitutive laws with principles of muscle fatigue, one can carry out even more realistic simulations of the musculoskeletal system. The main advantage of such complex models is the ability to carry out a more accurate assessment in terms of predicting cartilage overload.

Example Simulation

Raising of the lower arm by muscle activation: visualization of the Von Mises stress.