Bone Distribution Simulation Of Bone Remodeling Considering Damage-repair Factor

As a living tissue, bone is able to adapt its internal microstructure and,subsequently, mechanical properties to the varying mechanical and physiologicalenvironments in a process which is commonly known as bone remodeling. Themechanical engineering and biomechanics scientists have been trying to simulate thebehavior of bone remodeling by building a proper mathematic model. Nowadays,varied mechanical mechanisms of bone remodeling have been proposed. However, itis hard to illustrate a complicated bone remodeling process by a mechanical model.As the development of the computer technique, the Finite Element Method plays animportant role in the prediction of bone remodeling. Simulation of bone remodeling,which involves FEA, biomechanics, mechanical engineering and rehabilitationmedicine, play a vital role in predicting the development of bone and designing ofartificial prosthesis.The program, which simulates the process of bone adaptive remodeling, isexploited with the ANSYS Parameter Design Language based on the mentionedrequirement. This simulation of bone remodeling focuses on the following two mainpoints.Firstly, the author establishes a human proximal femur model after1000iterationsteps under the daily loading. The biomechanical stimulus was, as a rule, calculatedper element and bone density also renewed per element. Then we added the damagemechanism into the algorithm, with initial damage area defined, and continuedsimulating by controlling the boundary condition. The initial damage is neither a lossof elastic modulus nor a captivity planted in the finite element model. With a set ofmechanical stimulus and human physiology damage-repair cycle considered in thebone remodeling algorithm, the numerical result obtained in the simulation are verysimilar to reality in the case of an intact femur. From the evolution of the damage inthe proximal femur model, we can draw a conclusion that not only the damage areabut the whole model perform a series of repairing activities.Bone remodeling in disuse, as a result of lacking necessary stress level in thisresearch, is also an important issue in biomechanics of bone. As to the simulation ofosteoporosis aroused by ageing, the author renovated the load in model in every cycle time according to the muscle strength-age curve suggested by Burr DB. The resultindicated that load has great effect on simulation. Then the author establishes a longfemur model after the replacement of total hip to simulate the stress-shielding effectcaused by local area in disuse. After proposing the suggestions on adjusting properloads and reducing modulus of elasticity of prostheses, the ageing factor is alsoconsidered to complete the simulation.The results in this thesis have high correspondence to the human physiologicalcharacter. The prediction model can be used on the clinical attempt to help thepatients with bone disease.