مطالعه شبيه سازي المان محدود سوراخكاري استخوان

Study of finite element simulation of bone drilling

ﭼﮑﯿﺪه: ﺷﮑﺴﺘﮕﯽ اﺳﺘﺨﻮان ﻏﺎﻟﺒﺎ ﺑﺮ اﺛﺮ ﺳﻮاﻧﺢ و ﮐﻬﻮﻟﺖ ﺳﻦ ﺑﻮﺟﻮد ﻣﯽآﯾﺪ و ﺑﯽ ﺣﺮﮐﺖ ﺳﺎزي اﺳﺘﺨﻮان ﺷﮑﺴﺘﻪ ﺷﺪه ﺑﺎ اﯾﺠﺎد ﺳﻮراخ ﺗﻮﺳﻂ ﻣﺘﻪ و اﺗﺼﺎل ﻗﻄﻌﺎﺗﯽ ﮐﻪ ﺑﻪ آﻧﻬﺎ ﭘﯿﭻ ﻣﯽ ﺷﻮﻧﺪ اﻧﺠﺎم ﻣﯽﮔﯿﺮد. ﺗﻼش ﻫﺎي ﻣﺘﻌﺪدي ﺑﺮاي ﯾﺎﻓﺘﻦ راه ﺣﻠﯽ ﺟﻬﺖ ﮐﺎﺳﺘﻦ ﻧﮑﺮوزﻫﺎي ﺣﺮارﺗﯽ و ﻧﯿﺮوﻫﺎي ﺳﻮراﺧﮑﺎري ﺻﻮرت ﮔﺮﻓﺘﻪ اﺳﺖ. در اﯾﻦ ﻣﯿﺎن ﺷﺒﯿﻪ ﺳﺎزي ﮐﺎﻣﭙﯿﻮﺗﺮي ﺳﻮراخ ﮐﺎري ﺟﻬﺖ ﭘﯿﺶ ﺑﯿﻨﯽ ﻧﮑﺮوزﻫﺎي ﺣﺮارﺗﯽ و ﻧﯿﺮوﻫﺎ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ورود ﮐﺎﻣﭙﯿﻮﺗﺮﻫﺎي ﭘﺮ ﺳﺮﻋﺖ ﺟﺎﯾﮕﺎه وﯾﮋهاي ﯾﺎﻓﺘﻪ اﺳﺖ. در اﯾﻦ ﭘﮋوﻫﺶ ﺳﻮراخﮐﺎري اﺳﺘﺨﻮان ﺗﻮﺳﻂ ﻧﺮم اﻓﺰار اﻟﻤﺎن ﻣﺤﺪود ﺗﺠﺎري DEFORM/3D ﺷﺒﯿﻪ ﺳﺎزي ﺷﺪه اﺳﺖ. اﯾﻦ ﻧﺮم اﻓﺰار داراي ﻣﺎژول ﻣﺨﺼﻮص ﺷﺒﯿﻪ ﺳﺎزي ﻣﺎﺷﯿﻨﮑﺎري ﻣﯽﺑﺎﺷﺪ، ﻟﺬا ﮐﺎر ﺑﺎ اﯾﻦ ﻧﺮم اﻓﺰار آﺳﺎن ﺗﺮ و ﭘﺎﺳﺦ آن ﺳﺮﯾﻌﺘﺮ ﻣﯽﺑﺎﺷﺪ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻧﺎﻫﻤﺴﺎﻧﮕﺮد ﺑﻮدن اﺳﺘﺨﻮان از ﻣﻌﯿﺎر ﻫﯿﻞ ﺑﺮاي ﺗﻌﺮﯾﻒ ﻣﺎده اﺳﺘﻔﺎده ﮔﺮدﯾﺪ. ﺳﺮﻋﺖ دوراﻧﯽ و ﭘﯿﺸﺮوي ﺑﻪ ﻋﻨﻮان دو ورودي در ﺳﻪ ﺳﻄﺢ، ﻣﺠﻤﻮﻋﺎ 32=9 آزﻣﺎﯾﺶ ﻃﺮاﺣﯽ و ﺷﺒﯿﻪﺳﺎزي آن ﺑﻪ ﺻﻮرت ﺳﻪ ﺑﻌﺪي اﺟﺮا ﺷﺪ و ﺑﺎ ﻣﻘﺎدﯾﺮ ﺣﺎﺻﻞ از آزﻣﺎﯾﺶﻫﺎي ﺗﺠﺮﺑﯽ ﻣﻘﺎﯾﺴﻪ ﮔﺮدﯾﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺷﺒﯿﻪﺳﺎزي ﮐﺎﻣﭙﯿﻮﺗﺮي و آزﻣﺎﯾﺶ ﻫﺎي ﺗﺠﺮﺑﯽ ﻫﻤﺨﻮاﻧﯽ ﺑﺎﻻﯾﯽ را ﻧﺸﺎن داده اﺳﺖ. ﻣﯿﺰان ﺧﻄﺎي ﺑﯿﻦ ﻣﻘﺎدﯾﺮ اﻧﺪازهﮔﯿﺮي ﺷﺪه ﺗﺠﺮﺑﯽ و ﺷﺒﯿﻪ ﺳﺎزي، ﺣﺪاﮐﺜﺮ 10 درﺻﺪ ﺑﺮاي ﻧﯿﺮوي ﻻزم ﺟﻬﺖ ﻧﻔﻮذ ﻣﺘﻪ و 7 درﺻﺪ ﺑﺮاي دﻣﺎ ﺑﻮده اﺳﺖ.

Abstract: A Bone fracture often happens due to an accident and old age. Broken bones are fixed by connection elements that is mounting on the drill holes. So many attempts have been done to reduce thermal necrosis and drilling force. To predicate thermal necrosis and drilling force, Finite Elements Modeling (FEM) has been considerably utilized recently. In this study, bone drilling has been simulated by commercial DEFORM/3D. This software has a special module in machining process. So, it is user friendly, easier, and faster than other FE software. Due to the anisotropy of the bone, The Hill equation was used to define the material properties. Rotational speed and Feed rate as two inputs were changed in three levels, a total of 32 =9 tests were designed and its simulation was performed in three dimensions and compared with experimental tests. The results of computer simulations and experimental experiments have shown high agreement. The error rate between the experimental and simulation values was a maximum of 10% for force and 7% for temperature.