Elastic-plastic analysis of deformation induced by thermal stress in eutectic composites — II. Thermal expansion

In a previous paper, the authors discussed the classification of membrane stresses caused by piping loads resulting from restrained free thermal expansion. In that paper the authors proposed that although these stresses exhibit both primary and secondary characteristics, it is more appropriate to classify the resulting stresses as primary. In this paper, the authors present further FEA-based justification of this hypothesis. First, the vessel-nozzle intersection is modeled with 3D solid elements. Next, an elastic-plastic analysis of the previously examined piping/vessel layout is presented, with an examination of the final strain levels. Finally, a shakedown evaluation is performed. The results of these evaluations show that, unless additional analysis indicates otherwise, the membrane stresses resulting from restrained free thermal expansion piping loads should be classified as primary.

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On the Interaction of Thermal Membrane and Thermal Bending Stress in Shakedown Analysis

Volume 1: Codes and Standards ◽

10.1115/pvp2008-61628 ◽

2008 ◽

Cited By ~ 1

Author(s):

Wolf Reinhardt

Keyword(s):

Thermal Stress ◽

Bending Stress ◽

Membrane Stress ◽

Secondary Stress ◽

Elastic Plastic ◽

Plastic Analysis ◽

Thermal Bending ◽

Asme Code ◽

The Impact ◽

Current Code

When the primary plus secondary stress range exceeds 3 Sm, the current ASME Code rules on simplified elastic-plastic analysis impose two separate requirements to evaluate the potential for ratcheting. The range of primary plus secondary stress excluding thermal bending must be less than 3 Sm, and the thermal stress must satisfy the Bree criterion for thermal stress ratchet. It has been shown previously that this method can be unconservative, i.e. predict shakedown when elastic-plastic analysis shows ratcheting. This paper clarifies the interaction between thermal membrane and bending stress in the presence of a primary membrane stress. An analytical model is used to derive the closed-form ratchet boundary for combined uniform loading of this type. The impact of having stress gradients along the wall that are typical for discontinuities is studied numerically. Simple modifications of the current Code methods are suggested that would achieve a clearer and better-justified set of rules.

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A COMPARATIVE STUDY OF NUMERICAL METHODS OF ELASTIC - PLASTIC ANALYSIS

10.2514/6.1967-1122 ◽

1967 ◽

Cited By ~ 1

Author(s):

PEDRO MARCAL

Keyword(s):

Numerical Methods ◽

Comparative Study ◽

Elastic Plastic ◽

Plastic Analysis

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Out-of-Plane Thermal Expansion Coefficient and Biaxial Young’s Modulus of Sputtered ITO Thin Films

Coatings ◽

10.3390/coatings11020153 ◽

2021 ◽

Vol 11 (2) ◽

pp. 153

Author(s):

Chuen-Lin Tien ◽

Tsai-Wei Lin

Keyword(s):

Thin Films ◽

Thermal Expansion ◽

Thermal Stress ◽

Young’S Modulus ◽

Thermal Expansion Coefficient ◽

Expansion Coefficient ◽

Young's Modulus ◽

Heating Temperature ◽

Glass Substrates ◽

Ito Thin Films

This paper proposes a measuring apparatus and method for simultaneous determination of the thermal expansion coefficient and biaxial Young’s modulus of indium tin oxide (ITO) thin films. ITO thin films simultaneously coated on N-BK7 and S-TIM35 glass substrates were prepared by direct current (DC) magnetron sputtering deposition. The thermo-mechanical parameters of ITO thin films were investigated experimentally. Thermal stress in sputtered ITO films was evaluated by an improved Twyman–Green interferometer associated with wavelet transform at different temperatures. When the heating temperature increased from 30 °C to 100 °C, the tensile thermal stress of ITO thin films increased. The increase in substrate temperature led to the decrease of total residual stress deposited on two glass substrates. A linear relationship between the thermal stress and substrate heating temperature was found. The thermal expansion coefficient and biaxial Young’s modulus of the films were measured by the double substrate method. The results show that the out of plane thermal expansion coefficient and biaxial Young’s modulus of the ITO film were 5.81 × 10−6 °C−1 and 475 GPa.

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