• 제목/요약/키워드: Residual Deformation

검색결과 609건 처리시간 0.032초

사출 성형품의 금형내 잔류응력과 이형후 냉각에 의한 후변형 해석 (Deformation Analysis of Injection Molded Articles due to In-mold Residual Stress and Cooling after Ejection)

  • 양상식;권태헌
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 춘계학술대회논문집C
    • /
    • pp.251-256
    • /
    • 2001
  • Deformation analysis of injection molded articles whose geometry is considered as the assembly of the thin flat plates has been conducted. For the in-mold analysis, thermo-viscoelastic stress calculation of rheologically simple amorphous polymer and in-mold deformation calculation considering the in-plane mold constraint has been done. Free volume theory has been used for the non-equilibrium density state by the fast cooling. At ejection, the redistribution of stress together with instantaneous deformation has been considered. During out-of-mold cooling after ejection, thermoelastic model based on the effective temperature has been adopted for the calculation of deformation. Two typical mold geometries are used to test the numerical simulation.

  • PDF

장력법을 적용한 필릿용접변형 제어에 관한 연구 (On the Fillet Weld-Induced Deformation Control by Applying the Tensioning Method)

  • 이주성;김철호
    • Journal of Welding and Joining
    • /
    • 제27권4호
    • /
    • pp.38-43
    • /
    • 2009
  • As it has been well appreciated, the weld-induced deformation control is one of the most important issues from view point of efficiency in ship production. The weld-induced deformation is more serious in the case of thin plate block than in the case of relatively thick plate block, since, for example, heat affect zone of thin plates is wider than that of thick plates for the same heat input. Among weld-induced deformation, buckling deformation due to shrinkage and residual stress in weld line direction is one of the most serious deformation type. This paper is concerned with the controling the buckling deformation of thin plate fillet weld by applying the tensioning method. Weld experiments have been carried out for specimens with varying the magnitude and direction of tension load. The results are graphically represented to show the effect of tensioning method upon reducing the weld-induced deformation. From the present findings, its has been seen that tensioning method is one of the useful ways to control the weld-induced deformation of fillet weld of thin plates.

보수용접시 발생하는 변형 및 응력의 해석 및 정도 (Analysis of Deformation and Stress Generated by Repair Welding and Its Accuracy)

  • 장경호;이상형
    • 한국전산구조공학회논문집
    • /
    • 제17권4호
    • /
    • pp.365-374
    • /
    • 2004
  • 강구조물에 있어서 여러 가지 환경요인에 의해 균열 및 부식 등의 문제가 발생되고 있다. 이는 구조물의 내구성을 저하시키는 요인이 된다. 이와 같은 문제를 해결하기 위해 용접 보수${\cdot}$보강방법을 사용할 수 있다. 이러한 보수용접은 전단 및 용접과 같은 입열 과정을 필연적으로 수반하고 있다. 따라서 이러한 입열과정에 있어서 발생되는 잔류응력 및 변형의 예측${\cdot}$제어${\cdot}$방지는 구조물의 안전이라는 측면에서 볼 때 중요하다고 할 수 있다. 본 연구에서는 2차원 및 3차원 유한요소 해석을 수행하여 가스전단 및 아크용접에 의해 얻어진 절단 및 용접 잔류응력과 변형을 구하였으며, 2차원 및 3차원 해석기법에 따른 그 값의 정도를 명확히 하였다. 해석기법에 따라 2차원 및 3차원 해석을 수행하여 얻은 절단 및 용접 잔류응련의 분포 및 그 절대치는 유사한 값을 나타내었다.

Curing Induced Residual Stresses in Laminated Cylindrical Shells

  • Lee, Soo-Yong
    • Journal of Mechanical Science and Technology
    • /
    • 제14권1호
    • /
    • pp.19-29
    • /
    • 2000
  • A viscoelastic finite element analysis is presented to investigate residual stresses occurred in a laminated cylindrical shell during cure. An incremental viscoelastic constitutive equation that can describe stress relaxation during the cure is derived as a recursive formula which can be used conveniently for a numerical analysis. The finite element analysis program is developed on the basis of a 3-D degenerated shell element and the first order shear deformation theory, and is verified by comparing with an one dimensional exact solution. Viscoelastic effect on the residual stresses in the laminated shell during the cure is investigated by performing both the viscoelastic and linear elastic analyses considering thermal deformation and chemical shrinkage simultaneously. The results show that there is big difference between viscoelastic stresses and linear elastic stresses. The effect of cooling rates and cooling paths on the residual stresses is also examined.

  • PDF

온도 및 잔류응력을 고려한 플라스틱 부품의 점탄성 해석 (Thermal Viscoelastic Analysis of Plastic Part Considering Residual Stress)

  • 문형일;김헌영;최철우;정갑식
    • 소성∙가공
    • /
    • 제17권7호
    • /
    • pp.496-500
    • /
    • 2008
  • Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

궤도 차량 로드 휠 강도평가와 잔류 변형에 관한 연구 (A Study for Residual Deformation and Strength Evaluation on Road Wheel of a Tracked Vehicle)

  • 신국식;강성기
    • 한국기계가공학회지
    • /
    • 제10권3호
    • /
    • pp.47-52
    • /
    • 2011
  • A tracked vehicle is dependent on performance of power pack and suspension systems. Especially, road wheels which are components of suspension system contribute distributing vehicle weight on soil and preventing from misguiding tracks. In this study, the maximum force was calculated that a tracked vehicle is driven on the worst condition. And then, FE analyses were carried out to evaluate strength road wheel under maximum force condition. In standard of quality evaluation for road wheel, FE simulations and experimental works were carried out under thirty degree slant load of normal direction of shaft. And then, A relationship residual deformation for slant load was investigated. The result of this research is applicable to evaluate strength and to make use of basis data.

복합재 성형후 열잔류응력에 의한 변형 연구 (Prediction of Spring-in Deformation of Carbon Fiber Reinforced Composite by Thermal Residual Stress)

  • 김용승;김위대
    • Composites Research
    • /
    • 제30권6호
    • /
    • pp.410-415
    • /
    • 2017
  • 본 연구에서는 탄소섬유강화 복합재의 제작 시 열 잔류응력으로 인한 변형을 유한요소 프로그램 ABAQUS에서 User Subroutine을 이용한 유한요소 해석을 통해 예측한다. 탄소섬유강화 복합재의 변형에 영향을 주는 다양한 요인 중 온도구배, 제품 형상, 적층각 및 적층순서, 수지의 화학수축, 열 잔류응력을 고려한 복합재 성형을 해석하였다. 같은 형상의 실제 모델과 해석 모델의 결과를 비교한다. 또한 해석 결과를 분석하여 실제 제작의 오차에 적용하여 실제 제작에서의 성형 완성도를 높이는데 목적이 있다.

Anisotropy in Gum and Black Filled SBR and NR Vulcanizates Due to Large Deformation

  • Park, Byung-Ho;G.R. Hamed
    • Macromolecular Research
    • /
    • 제8권6호
    • /
    • pp.268-275
    • /
    • 2000
  • After imposing a large pre-strain, anisotropy increases with increasing residual extension ratio. Gums have very low residual extension ratio and exhibit little anisotropy, while black filled SBR and especially sulfur-cured carbon black filled NR have large set and anisotropy. For carbon black filled rubber, samples subjected to tensile loading in perpendicular to the pre-strain direction have the same stress-strain curves shape as the sample without pre-strain (=isotropic samples), but slightly lower modulus. However, compared to isotropic or perpendicular directional samples to pre-strain direction, samples subjected to tensile loading in parallel to the pre-strain direction show low stress at low deformation, but have high stiffness at high deformation. Normalized anisotropy changes with strain. The normalized anisotropy for various deformations is a linear function of residual extension ratio.

  • PDF

온도 및 잔류응력을 고려한 플라스틱 부품의 점탄성 해석 (Thermal Viscoelastic Analysis of Plastic Part Considering Residual Stress)

  • 문형일;김헌영;최철우;정갑식
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2008년도 춘계학술대회 논문집
    • /
    • pp.288-292
    • /
    • 2008
  • Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behaviour of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

  • PDF