• 제목/요약/키워드: longitudinal fracture

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Indirect Reduction and Spinal Canal Remodeling through Ligamentotaxis for Lumbar Burst Fracture

  • Kang, Wu Seong;Kim, Jung Chul;Choi, Ik Sun;Kim, Sung Kyu
    • Journal of Trauma and Injury
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    • 제30권4호
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    • pp.212-215
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    • 2017
  • The choice of the most appropriate treatment for thoracolumbar or lumbar spine burst fracture remains controversial from conservative treatment to fusion through a posterior or anterior approach. There are many cases where ligamentotaxis is used to reduce the burst fracture. However, indirect reduction using ligamentotaxis is often limited in the magnitude of the reduction that it can achieve. In our patient with severe burst fracture, we were able to restore an almost normal level of vertebral height and secure spinal canal widening by using only ligamentotaxis by posterior instrumentation. Before the operation, the patient had more than 95% encroachment of the spinal canal. This was reduced to less than 10% after treatment.

The microstructure and mechanical performance of high strength alloy steel X2M

  • Manigandan, K.;Srivatsan, T.S.;Freborg, A.M.;Quick, T.;Sastry, S.
    • Advances in materials Research
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    • 제3권1호
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    • pp.283-295
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    • 2014
  • In this paper, the microstructure, hardness, tensile deformation and fracture behavior of high strength alloy steel X2M is presented anddiscussed. The influence of both composition and processing on microstructure of the as-provided material and resultant influence of microstructure, as a function of orientation, on hardness, tensile properties and final fracture behavior is highlighted. The macroscopic mode and intrinsic microscopic features that result from fracture of the steel specimens machined from the two orientations, longitudinal and transverse is discussed. The intrinsic microscopic mechanisms governing quasi-static deformation and final fracture behavior of this high strength steel are outlined in light of the effects oftest specimen orientation, intrinsic microstructural effects and nature of loading.

Fracture analysis of functionally graded beams with considering material non-linearity

  • Rizov, Victor I.
    • Structural Engineering and Mechanics
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    • 제64권4호
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    • pp.487-494
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    • 2017
  • The present paper deals with a theoretical study of delamination fracture in the Crack Lap Shear (CLS) functionally graded beam configuration. The basic purpose is to analyze the fracture with taking into account the material non-linearity. The mechanical behavior of CLS was described by using a non-linear stress-strain relation. It was assumed that the material is functionally graded along the beam height. The fracture was analyzed by applying the J-integral approach. The curvature and neutral axis coordinate of CLS beam were derived in order to solve analytically the J-integral. The non-linear solution of J-integral obtained was verified by analyzing the strain energy release rate with considering material non-linearity. The effects of material gradient, crack location along the beam height and material non-linearity on fracture behavior were evaluated. The J-integral non-linear solution derived is very suitable for parametric studies of longitudinal fracture in the CLS beam. The results obtained can be used to optimize the functionally graded beam structure with respect to the fracture performance. The analytical approach developed in the present paper contributes for the understanding of delamination fracture in functionally graded beams exhibiting material non-linearity.

Investigation on Ultimate Strength of STS304L Stainless Steel Welded Connection with Base Metal Fracture Using Finite Element Analysis

  • Lee, HooChang;Kim, TaeSoo;Hwang, BoKyung;Cho, TaeJun
    • 국제강구조저널
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    • 제18권4호
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    • pp.1139-1152
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    • 2018
  • Many studies on the application of stainless steels as structural materials in buildings and infra-structures have been performed thanks to superior characteristics of corrosion resistance, fire resistance and aesthetic appeal. Experimental investigation to estimate the ultimate strength and fracture mode of the fillet-welded connections of cold-formed austenitic stainless steel (STS304L) with better intergranular corrosion resistance than that of austenitic stainless steel, STS304 commonly used has carried out by authors. Specimens were fabricated to fail by base metal fracture not weld metal fracture with main variables of weld lengths according to loading direction. All specimens showed a block shear fracture mode. In this paper, finite element analysis model was developed to predict the ultimate behaviors of welded connection and its validity was verified through the comparison with test results. Since the block shear behavior of welded connection due to stress triaxiality and shear-lag effects is different from that of bolted connection, stress and strain distributions in the critical path of tensile and shear fracture section were investigated. Test and analysis strengths were compared with those by current design specifications such as AISC, EC3 and existing researcher's proposed equations. In addition, through parametric analysis with extended variables, the conditions of end distance and longitudinal weld length for block shear fracture and tensile fracture were suggested.

무지 외반증에서 시행한 Scarf 절골술의 합병증 (Complications of Scarf Osteotomy for Hallux Valgus)

  • 남일현;안길영;문기혁;이영현;최성필;이태훈;이영훈
    • 대한족부족관절학회지
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    • 제18권4호
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    • pp.178-182
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    • 2014
  • Purpose: The purpose of this study was to evaluate the frequency of troughing and stress fracture, which are the major complications of scarf osteotomy, and to suggest methods to prevent these complications. Materials and Methods: We reviewed 243 cases of 137 patients treated with the scarf osteotomy for hallux valgus from January 2005 to December 2012. The mean follow-up period was 2.8 years. During the scarf osteotomy, a long oblique longitudinal osteotomy was performed in order to decrease the possibility of troughing and stress fracture. Radiographs of lateral view of the foot were obtained and the thicknesses of the first metatarsal base at the sagittal plane were measured and compared. Results: There was no troughing during fragment translation and screw fixation intraoperatively. Radiographs of lateral view of the foot taken preoperatively and at the last follow-up showed that the mean thickness of the first metatarsal was 22.4 mm preoperatively and 21.6 mm at the last follow-up, with a mean difference of 0.8 mm. And no stress fracture was observed. Conclusion: To prevent troughing and stress fracture, a long oblique longitudinal cut, parallel to the first metatarsal plantar surface, was performed, making both ends of the proximal segment truncated cone-shape, and securing the strong bony strut of the proximal segment. No troughing or stress fracture was experienced with scarf osteotomy.

Residual Stress and Fracture Analysis of Thick Plate for Partial Penetration Multi-Pass Weldment

  • Kim, Seok;Shim, Yong-Lae;Song, Jung-Il
    • Journal of Mechanical Science and Technology
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    • 제16권9호
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    • pp.1033-1039
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    • 2002
  • Partial penetration welding joint refers to the groove weld that applies to the one side welding which does not use steel backing and to both side welding without back gouging, that is, the partial penetration welding joint leaves an unwelded portion at the root of the welding area. In this study, we analyzed the residual stress and fracture on the thick metal plates that introduced the partial penetration welding method. According to the above-mentioned welding method, we could draw a conclusion that longitudinal stress and traverse stress occurred around the welding area are so minimal and do not affect any influence. We also performed the fracture behavior evaluation on the partial penetration multi pass welding with 25.4 mm thick plate by using the J-integral, which finally led us the conclusion that the partial penetration multi-pass welding method is more applicable and effective in handling the root face with less than 6.35 mm.

운동선수에서 횡방향 나사 고정 후 발생한 슬개골의 골절 - 증례 보고 - (Patellar fracture after transverse screw fixation in sports athletes - A case report -)

  • 라호종;김성태;하정구;김진구
    • 대한정형외과스포츠의학회지
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    • 제10권2호
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    • pp.109-112
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    • 2011
  • 전위성 슬개골 골절에 있어서 해부학적 정복 및 견고한 고정은 슬관절 기능과 강도, 그리고 조기 관절 운동 범위의 회복을 위해서 필요하다. 골절의 형태와 다양한 수술 기법에 따라서, 수술 후 많은 합병증들이 보고 되어져 왔다. 본 저자들은 운동 선수들에게서 발생한 종골절 1예와 이분성 슬개골의 골편 전위 골절 1예에서 유관 나사못 횡 고정술을 시행한 뒤 새로운 횡골절이 발생한 증례를 경험하여 보고하고자 한다.

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장대레일 철도 교량의 축력 영향인자 분석 (Influence Factors Affecting the Longitudinal Force of Continuous Welded Rail on Railroad Bridges)

  • 김경삼;한상윤;임남형;강영종
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(II)
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    • pp.385-390
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    • 2003
  • Recently, use of Continuous Welded rail(CWR) is increased for structural, economical reason but new problem is caused accordingly and phenomenon that give threat in traveling by ship stability of train is led. According as rail is prolonged, excessive relative displacement and longitudinal force can happen to rail by temperature change and external force. Specially, buckling or fracture of rail can happen in railroad bridges because relative displacement by bridge and properties of matter difference between rail grows and additional axial force happens to rail by behavior of bridge. According to several study, longitudinal force of rail in bridge is influenced with ballast resistance, elongation length, boundary condition, stiffness of framework. Non-linear behavior of ballast acts by the most important factor in interaction between rail and bridge. Therefore, must consider stiffness of bridge construction with non-linear characteristic of ballast and stiffness of base for accuracy with longitudinal force calculation and analyze. In this study, perform material non-linear analysis for longitudinal force of CWR and three dimensional buckling analysis to decide buckling force.

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극후물재 용접부 내부잔류응력 측정기술 및 특성 (Characteristic and Measurement Technology of Inner Welding Residual Stresses in Thick Steel Structures)

  • 박정웅;안규백;우완측
    • Journal of Welding and Joining
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    • 제34권2호
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    • pp.16-21
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    • 2016
  • Recent keywords of the heavy industries are large-scale structure and productivity. Especially, the sizes of the commercial vessels and the offshore structures have been gradually increased to deliver goods and explore or produce oil and natural gas in the Arctic. High heat input welding processes such as electro gas welding (EGW) have been widely used for welding thick steel plates with flux-cored arc welding (FCAW), especially in the shipbuilding industries. Because high heat input welding may cause the detrimental effects on the fracture toughness of the welded joint and the heat affected zone, it is essential to obtain the sufficient toughness of welded joint. There are well known that the fracture toughness like CTOD, CVN, and KIC were very important factors in order to secure the safety of the structures. Furthermore, the welding residual stress should be considered to estimate the unstable fracture in both EGW and FCAW. However, there are no references on the welding residual stress distribution of EGW and FCAW with thick steel plates. Therefore the welding residual stresses were very important elements to evaluate the safety of the welded structure. Based on the measurement results, the characteristics of residual stress distribution through thickness were compared between one-pass electron gas welding and multi-pass flux-cored arc welding. The longitudinal residual stress in the multi-pass flux-cored arc welding is tensile through all thicknesses in the welding fusion zone. Meanwhile, longitudinal residual stress of EGW is tensile on both surfaces and compressive at the inside of the plate. The magnitude of residual stresses by electron gas welding is lower than that by flux-cored arc welding.

탄소강 용접접합부의 모재블록전단내력에 관한 실험적 연구 (An Experimental Study on Block Shear Strength of Carbon Steel Fillet Welded Connection with Base Metal Fracture)

  • 이화영;황보경;이후창;김태수
    • 대한건축학회논문집:구조계
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    • 제34권1호
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    • pp.11-18
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    • 2018
  • An experimental study on the ultimate behaviors of the mild carbon steel (SPHC) fillet-welded connection is presented in this paper. Seven specimens were fabricated by the shielded metal arc welding (SMAW). All specimens failed by typical block shear fracture in the base metal of welded connections not weld metal. Block shear fracture observed in the base metal of welded connection is a combination of single tensile fracture transverse to the loading direction and two shear fractures longitudinal to the loading direction. Test strengths were compared with strength predictions by the current design equations and suggested equations by previous researchers. It is known that current design specifications (AISC2010 and KBC2016) and Oosterhof & Driver's equation underestimated overly the ultimate strength of the welded connection by on average 44%, 31%, respectively and prediction by Topkaya's equation was the closest to the test results. Consequently, modified equation is required to be proposed considering the stress triaxiality effect and material property difference on the block shear strength for base metal fracture in welded connections fabricated with mild carbon steel.