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곽대순(Dai-Soon Kwak),오택열(Taek-Yul Oh),한승호(Seung-Ho Han) Korean Society for Precision Engineering 2009 한국정밀공학회지 Vol.26 No.6
In this study, we performed the compressive strength test of trabecular bone in knee joint for measuring the elastic modulus and ultimate strength. The main knee joint is femorotibial articulation between the lateral and medial femorotibial condyle. In the case of osteoarthritis, some patients have only medial condylar osteoarthritis. We performed the mechanical test for comparison the difference of the each condylar strength. We used diamond core-drill and linear precision saw for making the specimens. Specimens were cored from both condyle in distal femur and proximal tibia in fresh cadaver (male 10, female 12), and tested by universal test machine with temperature control saline circulation system. Results of the test in distal femoral parts, averaged elastic modulus was 360.61±159.40㎫ for male, 150.89±70.65㎫ for female. Averaged ultimate strength was 6.79±2.91㎫ for male, 2.89±1.31㎫ for female. Male was 2.4 times stronger than female. In the proximal tibial parts, averaged elastic modulus was 108.80±52.88㎫ for male, 73.45±55.06㎫ for female. Averaged ultimate strength was 2.59±1.39㎫ for male, 1.75±1.16㎫ for female. Male was 1.5 times stronger than female. In the distal femoral condyle, medial condyle had more strength than lateral condyle at middle region. But lateral condyle had more strength than medial condyle at anterior & posterior regions (p<0.02). In the proximal tibial condyle, medial condyle had more strength than lateral condyle. (p<0.01).
곽대순(Dai-soon. Kwak),최광남(Kwang-Nam. Choi),김상국(Sang-Kuk. Kim),이상호(Sang-Ho. Lee),김태중(Tae-Joong. Kim),한승호(Seung-Ho. Han),오택열(T.Y. Oh) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
We performed the mechanical test for obtaining properties of femoral head. Tested sample was male and 35 years old. We measured bone mineral density by dual X-ray absorption method(DEXA). Results of DEXA, he has normal condition of bone density. His BMD 1.159g/㎠ and T-Score is 1.6. Tested femurs were harvested by surgical method from donated cadaver. We made 9 specimens in femoral head, 8 specimens in neck used by diamond core drill. Then we performed compressive test in saline solution at 38 . We obtained results that elastic modulus of femoral head was 0.439㎬, neck was 0.459㎬. Compressive strength of femoral head was 7.441㎫, neck was 7.095㎫. There was no significant difference of mechanical properties between left and right femoral head & neck. Invested local properties of femoral head have more strength superior and anterior side, femoral neck has more strength in superior and inferior side but other side except for superior has more weakness along the lateral side.
단일 과대하중에 의한 레이저 용접 판재의 피로균열 전파거동
곽대순(Dai-Soon Kwak),김석환(Seok Whan Kim),오택열(Taek Yul Oh) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.4
In this study, we investigated fatigue crack growth behavior of laser welded sheet metal due to a single overload. Fatigue specimens were made using butt joint of cold rolled sheet metal that was welded by C0₂laser. The fatigue crack propagation tests were performed in such a way that fatigue loading was parallel to the weld line while crack propagation was perpendicular to the weld line. Single overload was applied when fatigue crack tip was arrived near the weld line. The distances between the crack tip and the weld line at which a single overload was applied were 6, 4 and 2 ㎜. The effect of specimen thickness and overload ratio on the fatigue behavior was determined. The plastic zone size of crack tip due to the single overload was determined from the finite element analysis. For investigating fatigue crack growth behavior, we used different thickness specimen 0.9㎜ and 2.0㎜, and variable overload ratio applied fatigue crack propagation test. Also we used finite element analysis for investigating the plastic zone size of crack tip when single overload applied.