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A Method for Obtaining Residual Stress Distribution from Hypothetical Temperature Distribution of Fused Silica

A technology of imaginary temperature and residual stress, applied in the direction of material excitation analysis, force/torque/work measuring instrument, instrument, etc., can solve the problems of large residual stress prediction deviation, complex and cumbersome process, and obtain the specific distribution of residual stress, etc., to achieve easy Achieve and overcome complex and cumbersome, convenient and flexible effects

Active Publication Date: 2022-03-01
LASER FUSION RES CENT CHINA ACAD OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Existing studies have shown that to accurately predict fused silica CO 2 Laser-induced residual stress involves complex nonlinear plasticity problems. Simple models have large deviations in the prediction of residual stress. Although complex models predict residual stress more accurately, they require CO 2 The study of the whole process of laser action is extremely complicated and cumbersome, not only the specific laser parameters are required, but also the specific structural parameters dependent on the temperature of the material are required
Therefore, the existing fused silica residual stress research methods are difficult to quickly and conveniently obtain the specific distribution of residual stress

Method used

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  • A Method for Obtaining Residual Stress Distribution from Hypothetical Temperature Distribution of Fused Silica
  • A Method for Obtaining Residual Stress Distribution from Hypothetical Temperature Distribution of Fused Silica
  • A Method for Obtaining Residual Stress Distribution from Hypothetical Temperature Distribution of Fused Silica

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Effect test

Embodiment 1

[0062] Estimation of Fused Silica CO by Obtaining Residual Stress Distribution from Hypothetical Temperature Distribution of Fused Silica 2 Residual stress in laser irradiation area:

[0063] S1: Choose Corning 7980 fused silica with a size of 40mm (length)×40mm (width)×4mm (thickness). First, the fused silica is optically polished. After the polishing is completed, the fused silica is cleaned with deionized water and absolute ethanol respectively and dried, which can clean the fused silica simply and efficiently. Then, the CO is excited by RF 2 The laser passes the 1 / e through the optical system 2 A Gaussian spot with a diameter of 4.2 mm is irradiated on the fused silica. The laser power is first irradiated at 13.7 watts for 30 seconds for preheating. Then, the laser power is increased to 25.3 watts for 4 seconds, and then the laser is turned off. 2 After heating by laser irradiation, a heat-affected zone of fictitious temperature change is formed on the surface of the fu...

Embodiment 2

[0080] Adopt the method of the present invention to assess the CO reported by Matthews et al. (Proc.SPIE 2009,7504:750410) 2 The residual stress caused by the hypothetical temperature distribution in the axial depth of the laser irradiation point:

[0081] In this embodiment, steps S2, S3 and S4 are the same as in embodiment 1, the difference being steps S1 and S5:

[0082] S1: Fused silica CO obtained by confocal Raman spectroscopy reported by Matthews et al. (Proc.SPIE 2009,7504:750410) 2 The hypothetical temperature distribution of the axial depth of the laser irradiation point is as follows: Figure 8 Shown, respectively, 2300K peak temperature treated and quenched fused silica CO 2 Fused silica CO with peak temperature reduced from 2300K to 300K by a slope after laser irradiation point and 2300K peak temperature treatment 2 Laser irradiation point. According to CO 2 The characteristics of the spherical crown distribution of the hypothetical temperature distribution a...

Embodiment 3

[0089] The method of the present invention evaluates the residual stress of silica optical fiber:

[0090] S1: A single-mode optical fiber with a diameter of 125 μm and a cladding of pure silica, annealed at 1373K for 66 hours, and then quenched in dry air to obtain an optical fiber with a uniform temperature distribution at 1373K (J.Appl.Phys.2008,103:083506), and set doped GeO 2 The cores of have the same fictive temperature.

[0091] S2: Set the initial freezing state of the fictitious temperature of the silica fiber at 1373K as the residual stress zero point. During the subsequent temperature drop from 1373K, which is equal to the fictitious temperature, to room temperature, the silica fiber only undergoes a linear cooling and contraction process, while the fictitious temperature of 1373K The distribution no longer changes. According to the density and thermal expansion coefficient given by Huang et al. (J.Non-Cryst.Solids 1978,127:29-37) and GeO 2 The relationship betw...

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Abstract

The invention discloses a method for obtaining residual stress distribution from the imaginary temperature distribution of fused silica, which is carried out according to the following steps: S1: construct the imaginary temperature distribution of fused silica; S2: draw the initial freezing state curve and volume change curve; S3: calculate each Volume shrinkage at the position; S4: Obtain the distribution of relative volume strain; S5: Solve to obtain the residual stress distribution of fused silica. The above technical scheme is simple, accurate, and easy to implement, which overcomes the complicated and cumbersome technical problems of evaluating residual stress in existing methods, and solves the problem that the current virtual temperature state of glass only characterizes its structural state and cannot obtain residual stress through its distribution; method can not only obtain CO 2 The residual stress distribution of fused silica after laser action, and the residual stress of silica fiber can be obtained conveniently and flexibly, which has important application value in the field of fused silica processing.

Description

technical field [0001] The invention relates to the technical field of obtaining residual stress of optical elements, in particular to a method for obtaining residual stress distribution from the imaginary temperature distribution of fused silica. Background technique [0002] CO 2 Laser has been widely used in the processing of fused silica materials, such as: damage repair, surface polishing, cutting, surface pattern preparation, etc., and its processing usually requires depositing enough laser energy to heat the fused silica above the glass transition temperature, or even above the boiling point. Although fused silica has a relatively low coefficient of thermal expansion and is insensitive to the thermal gradient of the heating process, it can still accumulate large residual stress due to the limited relaxation time near the glass transition point when the temperature is rapidly cooled. Excessive residual stress is generally harmful. Stress and strain will not only caus...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L5/00G01N21/65
CPCG01L5/0047G01N21/65
Inventor 张传超廖威陈静蒋晓龙方振华张丽娟王海军蒋晓东朱启华
Owner LASER FUSION RES CENT CHINA ACAD OF ENG PHYSICS