Presentation on theme: "MIDDLE EAST TECHNICAL UNIVERSITY MECHANICAL ENGINEERING DEPARTMENT ME 590 SEMINAR Prepared by : Osman KILIÇ Supervisors : Prof. Dr. Turgut TÜMER Asst."— Presentation transcript:
MIDDLE EAST TECHNICAL UNIVERSITY MECHANICAL ENGINEERING DEPARTMENT ME 590 SEMINAR Prepared by : Osman KILIÇ Supervisors : Prof. Dr. Turgut TÜMER Asst. Prof. Ergin TÖNÜK Thesis Subject: “BIOMECHANICAL MODELLING OF HUMAN HAND”
ANATOMY OF THE WRIST BONES JOINTS
VOLAR (PALMAR) LIGAMENTS DORSAL LIGAMENTS
FUNCTIONS OF THE WRIST FLEXION EXTENSIONRADIAL DEVIATION ULNAR DEVIATION
SURGICAL & PATHOLOGICAL ASPECTS OF THE WRIST MODEL Changes in load distribution between carpal bones is very important for implant applications, surgical operations and ligament tears.
Pathological Example: Extra loading on Lunatum bone due to abnormal contact structure between Capitate and Lunate. Capitate Lunate Scaphoid Capitate Lunate Scaphoid Cup shaped part of the Capitate is shaved to remove extra load on Lunate.
IN LITERATURE Kinematics of wrist bones are not studied as a whole structure. Instead, there are studies containing a few bones which generally focus on contact forces and relative motion observations.
Recent studies are about finite element modelling of wrist bones. In all these models, most of the bones, ligaments and joints are missing. In order to have high a fidelity model of the wrist; bones, ligaments and joints should be studied as a whole. Radius
THESIS STUDIES 3D wrist bone models are taken from anthropometric database of ADAMS /Lifemodeler: Sex : Male Age : 360 months Height: 1778 mm Weight: 77 kg The wrist is modeled by using Msc. ADAMS software.
Motion Analysis of the Wrist Bones SPINNING ROLLING SLIDING
Contacts and jonts between the wrist bones are analyzed Joints are taken as spherical joints.
52 different ligaments with different stiffness and damping coefficients are used in the model
JOINTS BUSHING ELEMENTS In the model, rotational spring and damper coefficients are ~1% of translational spring and damper coefficients. 20 bushing elements (joints) are used in the model (Coordinates are local coordinates of the bushing elements)
CONTACT e > 1 stiffening stiffness e < 1 softening stiffness Penetration distance
EXTENSION MOTION The model gives correct results for flexion but for extension limit is exceeded
RADIAL DEVIATION MOTION
ULNAR DEVIATION MOTION
~50% ~30%~20% ~60% ~20%
CONCLUSION & FUTURE WORK For flexion, extension, radial and ulnar deviation motions a different analysis and a model will be developed Joint and ligament variables (stiffness & damping coefficients) will be revised for each different model Surface discontinuities on the bones causes errors in the results More accurate bone structures will be taken from CT data