Biomedical Engineers are looking for a better way to simulate Biomechanics Simulation. LeTourneau University turns to MD Adams to simulate a subject specific Knee model using rigid body dynamics. The result from this research shows that the contact force on the Medial and Lateral Condyles showed similar trends between the MD Adams model and FEA model.
LeTourneau University's Course in Biomechanics is using MSC Software's MD Adams/View to develop a subject specific knee model using rigid body dynamics. The keys features of MD Adams/View that have been most instrumental to our study were the ability to create and modify point forces, contact definitions, connectors, construction geometry points and general constraints. The final MD Adams model was developed to validate our LS DYNA FEA model. Findings showed strong similarities between the MD Adams and Finite Element Analysis (FEA) model results.
Procedure:
Experimental data was obtained using a motion capture system to collect position data, Electromyography (EMG), and Ground Reaction Force (GRF) in a squatting trial. The soft tissues of the knee were segmented, processed, and used to develop a rigid body model of the knee. The soft tissues were used to build both models.
Static Knee Model
A quasistatic knee model was initially created by placing a load onto the tibia while the femoral cartilage was locked in all Degrees-of-Freedom (DOFs). The ligaments of the knee were springs with the force displacement curves obtained from literature. The ligaments held the knee in place.
Dynamic Knee Model
After the completion of the static knee model, the positions from the hip and ankle center were placed in splines to drive the motion of the knee, and the femoral cartilage is unlocked and allowing flexion and extension the knee.
Results:
The contact force on the Medial and Lateral Condyles showed similar trends between the MD Adams model and FEA model thereby validate the integrity of each other.
Improvements to come:
Because the quadriceps wrap over the femur during deep flexion, work is being done to figure out ways to improve a muscle wrapping technique. There are plans to use optimized muscle forces and obtain more experimental data to improve the accuracy of our models.
