Structure optimization of electrical penetration assemblies: Experimental facts and stress field analysis by the finite element method

Cai, Yangyang; Hu, Kezhen; Li, Shenhou; Zhu, Qinglin; Zheng, Liaoying; Gong, Keqian; Zhang, Yong

doi:10.1016/j.mtla.2022.101381

Cited by 6 publications

(5 citation statements)

References 45 publications

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“…XFEM was used to simulate crack initiation and propagation, as it allows the position of the crack in the material to be completely free, rather than relying on mesh generation. The glass was simulated as a linear elastic material and would break after a certain tensile strength was reached, with a Young's modulus of 76300 MPa measured by compression method using a universal testing machine (SHIMADZU, WDW-100, Jinan, China) at a loading rate of 0.2 mm min −1 and Poisson's ratio of 0.33, which had been confirmed in our previous study [4,26]. Excessive first principal stress is the main cause of glass fracture, so the maximum principal stress (MAXPS) criterion was selected.…”

Section: Finite Element Analysissupporting

confidence: 55%

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Gong

Cai

Liu

et al. 2023

Mater. Res. Express

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In order to evaluate the influence of preform preparation processes on thermal cycle stability of glass-to-metal seals, this work embraced two different methods to produce the preform for seals. For the conventional powder metallurgy (PM) method, the molten glass was quenched to form frits, then the frits were ball milled to prepare glass powders. These glass powders were pressed into green bodies and heated to prepare preforms. While for the casting-machining (CM) method, the molten glass was cast into a graphite mold and annealed before accurate machining to preforms. In contrast to the PM method, the CM method provided an ultralow-porosity preform structure and a low porosity glass seal region. Field emission scanning electron microscope (FE-SEM) was conducted to investigate the bubbles and cracks in glass region. Furthermore, thermal cycling tests confirmed that these two tremendously different glass regions strongly affected the thermal cycle stability of the seals. To support the understanding of cracking in seals, the damage features of the samples were observed by FE-SEM and the extended finite element method (XFEM) was used to simulate the crack initiation and propagation. The experimental results demonstrated that cracking in the seals made from CM preforms occurred in the glass region near the sealing interface. However, cracks initiated from the bubbles in the seals made from PM preforms, which was verified by the XFEM simulation results. In addition, the CM seals demonstrated little degradation of the leakage rate until 105 thermal cycles, while cracking was found in the PM seals after 70 thermal cycles, indicating a decreased thermal cycle stability and resulting in hermetic failure.

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Section: Finite Element Analysissupporting

confidence: 55%

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Gong

Cai

Liu

et al. 2023

Mater. Res. Express

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“…Additionally, a novel trait of stress distribution was observed in which tensile stress concentration appeared at both ends of the diameter of the pores. It was generally assumed that the rapid cooling and shrinking of the 304SS metal housing exerted a large compressive stress concentration on the glass along the radial direction of the seal (blue arrows in Figure 8G), 4,16 and it is shown in Figure 8I that the location of tensile stress concentration coincidently appeared perpendicular to the site of compressive stress (orange arrows in Figure 8G). Here, the arrows indicate the location of the stress concentration rather than the directional stress tensors since the hydrostatic stress is a scalar.…”

Section: Stress Distribution Around Poresmentioning

confidence: 99%

“…FEA has been applied in the field of stress simulation in GtM seals thanks to the rapid development of computer performance. [16][17][18][19] However, establishing intricate finite element models for viscoelastic glass and for glass-metal interfaces formed by chemical reactions can be challenging, resulting in fundamental limitations for microregion stress analysis using FEA. 17,18 Therefore, a novel method is urgently needed to advance the determination of stresses in GtM seals.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, stress detection and simulation methods for glass or glass matrix composites include X-ray diffraction (XRD), [6][7][8] nuclear magnetic resonance (NMR), 9 fiber Bragg grating (FBG), 10,11 indentation, [12][13][14][15] finite element analysis (FEA), [16][17][18][19] and so on. XRD is utilized for stress detection based on the principle that the diffraction peak can be shifted by stress within the crystal phase.…”

Section: Introductionmentioning

confidence: 99%

“…This approach, while efficient and inexpensive, causes irreversible damage to the surface and relies primarily on subjective assessment of the crack length by operators, limiting its spatial‐ and stress‐resolution. FEA has been applied in the field of stress simulation in GtM seals thanks to the rapid development of computer performance 16–19 . However, establishing intricate finite element models for viscoelastic glass and for glass‐metal interfaces formed by chemical reactions can be challenging, resulting in fundamental limitations for microregion stress analysis using FEA 17,18 …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photoluminescence spectroscopy to detect microregion stress distribution in glass‐to‐metal seals

Liu,

Gong,

Cai

et al. 2024

J Am Ceram Soc.

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The stress distribution in sealing glass is one of the most concerning issues for glass‐to‐metal (GtM) seals. In this study, photoluminescence spectroscopy was applied by exploiting the piezospectroscopic effect of Cr‐doped α‐Al2O3 (ruby), and the overall stress distribution along the radius of a concentric seal was detected and analyzed. It was discovered that the compressive stress first increased and then decreased at the edge of the seal. The maximum compressive stress of 91 MPa was detected at ∼20 µm from the interface and was ascribed to the interaction between the glass and surface oxide film of the metal. Stress distributions in pore regions were also investigated and obvious stress fluctuations were observed clustering around pores. A circle of compressive stress was observed around the pores in a single glass without a metal housing; for the pores in the center of the concentric seal, the stress distribution was dominated by the inner contraction of the metal housing; and for the pores near the edge of the seal, the concentration of tensile stress located perpendicular to that of the compressive stress. This study demonstrates a high‐resolved and nondestructive method to detect the stress field and explores the potential for future tailorability of stress distribution in GtM seals.

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Effects of Al2O3 nanoparticles on the properties of glass matrix composites for sealant applications

Liu

Cai

Gong

et al. 2023

Ceramics International

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Structure optimization of electrical penetration assemblies: Experimental facts and stress field analysis by the finite element method

Cited by 6 publications

References 45 publications

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Photoluminescence spectroscopy to detect microregion stress distribution in glass‐to‐metal seals

Effects of Al2O3 nanoparticles on the properties of glass matrix composites for sealant applications

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