11379

10454

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي مكانيك

1395

چهارده، 88ص.: مصور

محمد مشايخي

محمدتقي كريمي

محمود كدخدايي، مهدي سلماني تهراني

1395/06/03

مهندسي مكانيك

ID10454

چكيده امروزه با توجه به شكايع شكدن بيماريها و ضايعات ارتوپدي مختلف نظير پوكي استخوان و ضايعات نخاعي تعداد افرادي كه به اين نوع از بيماريها مبتال ميشكوند افزايش يافته است از اين رو بررسي و تحقيق پيرامون موضوعات مربوط به اين بيماريها به منظور بهبود روشهاي درماني از اهميت ويژهاي برخوردار است دانستن شرايط مكانيكي عضو مورد بررسي نظير توزيع تنش نقش مهمي را در درمان اين بيماريها ايفا ميكند به گونهاي كه در برخي موارد نداشكتن اطالعات دقيق از شكرايط محيطي و مكانيكي عضكو سكبب بروز كك ك مشكالت حركتي پس از انجام مراحل درمان ميشود هدف اين پژوهش استخراج نيروها و توزيع تنش در استخوان ران يك بيمار مبتال به پرتس به عنوان يك ضايعه ارتوپدي شايع در كودكان و بررسي اثر چرخش استخوان در طول حركت و حضور غضروف بر اين توزيع تنش اسكت براي دسكتيابي به اين هدف تحليل اجزاي محدودي بر روي اسكتخوان ران سالم و معيوب بيمار به كمك استخراج هندسه استخوان ران از تصاوير اسكن اختصاص خواص مكانيكي بر اساس تراكم استخوان و محاسبه نيروها از طريق شبيهسازي حركت شخص انجام ميگيرد نتايج نشككان دهنده وجود تمركز تنش در ناحيه سككر اسككتخوان ران معيوب و مقادير بزر تر تنش و نيرو در اين اسككتخوان نسبت به اسخوان سالم ناشي از اثرات بيماري پرتس است همچنين چرخش استخوان و يكسان شدن راستاي آن با راستاي اصلي استخوان در هنگام اعمال نيرو سبب افزايش مقادير تنش فونميزز و تنش برشي ميشود كه احتمال تغييرشكل استخوان را افزايش ميدهد حضور غضكروف به علت توزيع نيروي وارده بر روي منطقه وسكيعتري از ناحيه سكر اسكتخوان سكبب يكنواخت شدن توزيع تنش در استخوان و كاهش مقادير تنش ميشود كلمات كليدي استخوان ران پرتس بافت نرم شبيهسازي اجزاي محدود استخوان ران 3

Force and Stress Analysis of Femur and Cartilage in Perthes Disease Ebrahim Setare e setare@me iut ac ir Date of Submission 2016 06 20 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mohammad Mashayekhi Mashayekhi@cc iut ac irAbstractBiomechanics is the application of mechanical principles on living organisms for the purpose ofunderstanding better the influence of mechanical loads on the structure properties and function of livingthings In recently experimental techniques in biomechanics have undergone enormous developments Having a clearer understanding of the organ s mechanical conditions make further enhancements in prostheticdevices and improvements may be made for surgery and implant designs to help patients operations Compared to the other limb bones have most portion in musculoskeletal injuries One of the most importantbone in human body is femur In human anatomy femur is the longest and largest bone in the body that formspart of the hip joint at the proximal The entire weight of the upper body from the hip onwards is transmittedto the legs through the two femurs The femur performs various functions that help to maintain mobility ofthe body An incident diseases in children that affects the head of the femur is Perthes In Perthes disease the blood supply to the rounded head of the femur is temporarily disrupted Without an adequate blood supply the bone cells die and as a result the bone softens and breaks down The goal of treatment this disease is torelieve painful symptoms protect the shape of the femoral head and restore normal hip movement There aremany treatment options for Perthes disease such as observation bed rest and crutches a plaster cast or specialleg brace or surgery All of these treatments can be improved by knowing the clear details of mechanicalproperties of femur such as stress distribution within femur and forces that are applied to the femur The aim of this study is extraction stress distribution and forces acting on the femur of the person with Perthesdisease The head of right femur has been deformed and exited from hip socket due to Perthes caused personlimping while walking To reach this goal CT scans of a patient will first be processed and a 3D model ofthe hip region created in Mimics software The model was then exported to a pre processing software calledHypermesh in order to generate volumetric mesh Then the ten mechanical properties assigned to meshedmodel of femur according to bone density and gray values of each part Then the forces that are applied tothe head of femur during walking is determined by simulating the movement of persons in Opensim software After that a finite element analysis be carried on femur model to evaluate the stress distribution in Perthesand health right and left femur A maximum reaction force acting on the head of the femur was applied onthe region that has been created from contact of pelvis and femur while fixed support is provided at the endof femur Finally the effect of femur rotation during the movement of the person and effect of cartilage onstress distribution within femur was evaluated The results show that stress concentration occurred in head ofPerthes femur and greater force and stress applied on this femur rather than health femur Also rotation offemur and placed it in original state at the time of maximum force caused the amount of stress and shear stressincreased in femur Due to femur is weaker in shear stress rather than normal stress rotation of femurparticular femur s flexion is the more critical state in femur The inclusion of cartilage caused a significantdecrease in magnitude of stresses and more uniform stress distribution within the femur Keywords Femur Perthes Soft Tissue Finite Element Analysis of Femur

محمد مشايخي

محمدتقي كريمي

محمود كدخدايي، مهدي سلماني تهراني