• 제목/요약/키워드: Thermomechanical behavior

검색결과 96건 처리시간 0.022초

DEPTH AND LAYOUT OPTIMIZATIONS OF A RADIOACTIVE WASTE REPOSITORY IN A DISCONTINUOUS ROCK MASS BASED ON A THERMOMECHANICAL MODEL

  • Kim, Jhin-Wung;Koh, Yong-Kwon;Bae, Dae-Seok;Choi, Jong-Won
    • Nuclear Engineering and Technology
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    • 제40권5호
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    • pp.429-438
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    • 2008
  • The objective of the present study is the depth and layout optimizations of a single layer, high level radioactive waste repository in a discontinuous rock mass with special joint set arrangements. A single layer repository model, considering variations in the repository depths, pitches, and tunnel spacings, is used to analyze the thermomechanical interaction behavior. It is assumed that the repository is constructed in saturated granite with joints; the PWR spent fuel in a disposal canister is installed in a deposition drift which is then sealed with compacted bentonite; and the backfill material is filled in the repository tunnel. The decay heat generated by the high level radioactive wastes governs the thermomechanical behavior of the near field rock mass of the repository. The temperature and displacement behavior of the repository is influenced more by the pitch variations than the tunnel spacing and repository depth. However, the stress behavior is influenced more by the repository depth variations than the pitch and tunnel spacing. For the final selection of the tunnel spacing, pitch, and repository depth, other aspects such as the nuclide migration through a groundwater flow path, construction costs, operation costs, and so on should be considered.

Thermomechanical Behaviors of Shape Memory Alloy Thin Films and Their Application

  • Roh, Jin-Ho;Lee, In
    • International Journal of Aeronautical and Space Sciences
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    • 제7권1호
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    • pp.91-98
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    • 2006
  • The thermomechanical behaviors of SMA thin film actuator and their application are investigated. The numerical algorithm of the 2-D SMA thermomechanical constitutive equation is developed and implemented into the ABAQUS finite element program by using the user defined material (UMAT) subroutine. To verify the numerical algorithm of SMAs, the results are compared with experimental data. For the application of SMA thin film actuator, the methodology to maintain the precise configuration of inflatable membrane structure is demonstrated.

Al-Mg-Si합금의 고온 소성 변형 거동 (Plastic Deformation Behavior Of Al-Mg-Si Alloy At The Elevated Temperature)

  • 권용남;이영선;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 추계학술대회논문집
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    • pp.172-175
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    • 2003
  • Thermomechanical behavior of Al-Mg-Si alloys have been studied to investigate the effect of microstructural features such as pre-existing substructure and distribution of particles on the deformation characteristics. The controlled compression tests have been carried out to get the basic information on how the alloy responds to temperature, strain amount and strain rate. Then hot forging of Al-Mg-Si alloys has been carried out and analyzed by the comparison with the compression tests. Microstructural features after forging have been discussed in terms of the thermomechanical response of Al-Mg-Si alloys. As already well mentioned, we have found that the deformation of Al-Mg-Si at the elevated temperature brought the recovered structure on most conditions. In a certain time, however, abnormally large grains have been found as a result of deformation assisted grain growth, which means that hot forging of Al-Mg-Si alloys could lead to a undesirable microstructural variation and the consequent mechanical properties such as fatigue strength.

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Al-Mg-Si 합금의 고온 소성 변형 거동 (Plastic Deformation Behavior of Al-Mg-Si Alloys at the Elevated Temperatures)

  • 권용남;이영선;이정환
    • 소성∙가공
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    • 제13권1호
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    • pp.27-32
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    • 2004
  • Thermomechanical behavior of Al-Mg-Si alloys was studied to investigate the effect of microstructural features such as pre-existing substructure and distribution of particles on the deformation characteristics. The controlled compression tests were carried out to get the information on how the alloy responds to temperature, strain amount and strain rate. Then hot forging of Al-Mg-Si alloys carried out and analyzed by the comparison with the compression tests. Microstructural features after forging were discussed in terms of the thermomechanical response of Al-Mg-Si alloys. As already well mentioned, we found that the deformation of Al-Mg-Si at the elevated temperature brought the recovered structure on most conditions. In a certain time, however, abnormally large grains were found as a result of deformation assisted grain growth, which means that hot forging of Al-Mg-Si alloys could lead to a undesirable microstructural variation and the consequent mechanical properties such as fatigue strength.

방사성폐기물 지층처분을 위한 화강암의 열역학적 파괴거동 연구 (A Study on Thermomechanical Failure Behavior of Granites for Radioactive Waste Repository)

  • 양형식;장명환
    • 터널과지하공간
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    • 제6권1호
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    • pp.69-74
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    • 1996
  • High temperature confined compressive tests for thermomechanical failure criteria were carried out for Iksan and Whandeung granites. Authors suggested new polynomial type failure coefficient functions by which conventional Hoek-Brown failure criteria was extended to thermomechanical one. Obtained results are as follow; 1) Failure coefficients, m and s of Hoek and Brown's empirical failure criteria were decreased as temperature increased. 2) Theoretically calculated values by suggested equations and experimented ones by confined compressive test were well coincided.

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Effect of irradiation temperature on the nanoindentation behavior of P92 steel with thermomechanical treatment

  • Huang, Xi;Shen, Yinzhong;Li, Qingshan;Li, Xiaoyan;Zhan, Zixiong;Li, Guang;Li, Zhenhe
    • Nuclear Engineering and Technology
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    • 제54권7호
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    • pp.2408-2417
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    • 2022
  • The nanoindentation behavior of P92 steel with thermomechanical treatment under 3.5 MeV Fe13+ ion irradiation at room temperature, 400 and 700 ℃ was investigated. Pop-in behavior is observed for all the samples with and without irradiation at room temperature, while the temperature dependence of pop-in behavior is only observed in irradiated samples. The average load and penetration depth at the onset of pop-in increase as the irradiation temperature increases, in line with the results of the maximum shear stress. Irradiation induced hardening is exhibited for all irradiated samples, but there is a significant reduction in the hardness of sample irradiated at 700 ℃ in comparison to the samples irradiated at room temperature and 400 ℃. The ratio of hardness to elastic modulus for all samples decreases with increasing penetration depth except for samples at 700 ℃. With the increasing of irradiation temperature, the ratio of the irreversible work to the total work gradually decreases. In contrast, it increases for samples without irradiation.

가공열처리 및 2단시효처리에 의한 8090알루미늄 합금의 석출거동 (PRECIPITAlON BEHAVIOR OF 8090 ALUMINIUM ALLOY BY HERMOMECANICAL AND DUPLEX AGING TREAMENT)

  • 이학용;김석원;우기도
    • 열처리공학회지
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    • 제7권4호
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    • pp.270-276
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    • 1994
  • The effects of thermomechanical and duplex aging treatment on precipitation behavior were investigated for the 8090 aluminium alloy by tensile test, hardness test, plane-strain fracture toughness test and electron microscope. Both pre-aging stretch and duplex aging with pre-aging stretch were effective to homogenize the distribution of S' phase in this alloys. The latter makes more homogeneous distribution of S' phase than that of the former, but the sizes of S' phase in both specimens are almost same. The size and distribution of 0' phase were not changed by thermomechanical or duplex aging treatment. The strength was increased by thermomechanical treatment, but the elongation was decreased. Duplex aging treatment couldn't change the strength and elongation. Pre-aging stretch and duplex aging with pre-aging stretch have same effect on the strength and elongation. The increase of strength by thermomechanical treatment in 8090 alumunium alloy was caused by homogeneously precipitated S' phase.

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Experimental training of shape memory alloy fibres under combined thermomechanical loading

  • Shinde, Digamber;Katariya, Pankaj V;Mehar, Kulmani;Khan, Md. Rajik;Panda, Subrata K;Pandey, Harsh K
    • Structural Engineering and Mechanics
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    • 제68권5호
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    • pp.519-526
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    • 2018
  • In this article, experimental training of the commercial available shape memory alloy fibre (SMA) fibre under the combined thermomechanical loading is reported. SMA has the ability to sense a small change in temperature (${\geq}10^{\circ}C$) and activated under the external loading and results in shape change. The thermomechanical characteristics of SMA at different temperature and mechanical loading are obtained through an own lab-scale experimental setup. The analysis is conducted for two types of the medium using the liquid nitrogen (cold cycle) and the hot water (heat cycle). The experimental data indicate that SMA act as a normal wire for Martensite phase and activated behavior i.e., regain the original shape during the Austenite phase only. To improve the confidence of such kind of behavior has been verified by inspecting the composition of the wire. The study reveals interesting conclusion i.e., while SMA deviates from the equiatomic structure or consist of foreign materials (carbon and oxygen) except nickel and titanium may affect the phase transformation temperature which shifted the activation phase temperature. Also, the grain structure distortion of SMA wire has been examined via the scanning electron microscope after the thermomechanical cycle loading and discussed in details.

리올러지 모델을 이용한 열적 기계적 변형 거동 모사 (A Description of Thermomechanical Behavior Using a Rheological Model)

  • 이금오;홍성구;이순복
    • 대한기계학회논문집A
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    • 제30권7호
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    • pp.757-764
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    • 2006
  • Isothermal cyclic stress-strain deformation and thermomechanical deformation (TMD) of 429EM stainless steel were analyzed using a rheological model employing a bi-linear model. The proposed model was composed of three parameters: elastic modulus, yield stress and tangent modulus. Monotonic stress-strain curves at various temperatures were used to construct the model. The yield stress in the model was nearly same as 0.2% offset yield stress. Hardening relation factor, m, was proposed to relate cyclic hardening to kinematic hardening. Isothermal cyclic stress-strain deformation could be described well by the proposed model. The model was extended to describe TMD. The results revealed that the hi-linear thermomechanical model overestimates the experimental data under both in-phase and out-of-phase conditions in the temperature range of $350-500^{\circ}C$ and it was due to the enhanced dynamic recovery effect.

열기계적 분석법으로 측정된 레진 포뮬레이션의 경화 수축 특성 (Cure Shrinkage Characteristics of Resin Formulations by Thermomechanical Analysis)

  • 서안나;이종현
    • 대한금속재료학회지
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    • 제50권9호
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    • pp.629-636
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    • 2012
  • Volume shrinkage behavior accompanying the cure of resin formulations might be a critical factor when assembly processes using polymer materials are considered. In this study, cure shrinkage behavior with respect to resin formulation type and heating method was measured on sandwich structure samples by a thermomechanical analyzer (TMA). Quartz, used as a cover material for the sandwich structure, indicated the coefficient of thermal expansion close to $0ppm/^{\circ}C$. When a dynamic heating mode was conducted, a squeeze-out region and a cross-linking region for each resin formulation could be separated clearly with overlapping differential scanning calorimeter results on the TMA results. In addition, a cure shrinkage dominant region and a thermal expansion dominant region in the cross-linking region were distinguished. Consequently, the degree of cure at the initiation of the thermal expansion dominant region was successfully measured. Measurement of all resin formulations indicated the thermal expansion behavior exceeded cure shrinkage before full cure.