الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Tibia bone is the most common fractured bone in humans. Fracturefixation by bone-plates and screws is proposed to hold the fractured bone and provide healing by formation of callus texture. In this work, a numerical study of new developed bone-plates with gaps in terms of stress distribution is evaluated. 3-D finite element models for a fractured tibia with metallic (stainless steel and titanium alloy) and composite (carbon hydroxyapatite and carbon epoxy) boneplates are analyzed using ANSYS workbenc 14.5 program. Bone-plates with different gaps (0.2 mm, 0.4 mm and 0.7 mm), and a contact bone-plate with no gap are examined. von Mises stresses along the fractured site, along the tibia bone and on the bone-plate are also studied at different healing stages under the same loading and boundary conditions. The results of stresses have been compared and presented in graphs. It is found that bone-plates model with a gap value 0.7 mm provide higher compressive stress along the fractured site and along the bone than the other bone-plate models. This bone-plates model also decrease the transformed stresses to the bone-plate. Composite bone-plates materials achieve better results than metallic bone-plates materials. Along the fractured site, using composite (carbon hydroxyapatite, carbon epoxy) bone-plates materials with 0.7 mm gap increasing the stresses by average 48% at the first healing stage, 12% at the second healing stage, 10% at the final stage compared to the contact bone-plate of the same material. Along the bone, the average increasing in stress at the final healing stage is 17% for carbon hydroxyapatite and 18% for carbon epoxy bone-plates materials with 0.7 mm gap compared to the contact one of the same material. The average increasing in stress along the fractured site at the final healing stage is 18% for carbon hydroxyapatite and 10% for carbon epoxy bone-plates materials with 0.7 mm gap compared to stainless steel bone-plates material of the same model (0.7 mm gap). The average increasing in stress along the bone at the final healing stage is 21% for carbon hydroxyapatite and 16% for carbon epoxy bone-plates materials with 0.7 mm gap compared to stainless steel boneplates material of the same model (0.7 mm gap). Therefore, using composite bone-plate model with 0.7 mm gap will accelerate the healing and offered less stress shielding to the bone.