In Situ Stress Measurement Method Based on X-Ray Diffraction under Biaxial Tensile Loading

The purpose of this investigation is to detect damage from stress distribution in the surface of near pre-crack tip by using X-ray diffraction technique during biaxial tension test. An measurements apparatus to measure stress distribution along pre-crack direction was fabrication by use of a biaxial tensile test device and a stress analyzer based on single exposure technique with one position sensitive proportional counter. Stress distribution with different tensile applied stress ratios were measured during biaxial tension test. As results, the shape of actual stress was keeping increase with increasing tensile applied stress. At maximum applied stress, the residual stress increases with the increasing distance from the crack tip; after reaching a maximum it gradually diminish.

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Measurement of Residual Stress Distribution of Ground Silicon Nitride by Glancing Incidence X-ray Diffraction Technique

Advances in X-ray Analysis ◽

10.1154/s0376030800022746 ◽

1995 ◽

Vol 39 ◽

pp. 331-338

Author(s):

Yoshihisa Sakaida ◽

Keisuke Tanaka ◽

Shintaro Harada

Keyword(s):

Residual Stress ◽

Surface Layer ◽

Stress Distribution ◽

Stress Measurement ◽

Scintillation Counter ◽

Ground Surface ◽

Residual Stress Distribution ◽

X Ray Diffraction ◽

X Ray ◽

Very High

A new method of X-ray stress measurement was proposed to estimate non-destructively the steep residual stress distribution in the surface layer of ground Si3N4. We assumed an exponential decrement of the residual stress near the ground surface, and derived a formula for the lattice strain as a function of sin2Ψ. In the experiments, the diffraction angles were measured on the ground surface for a widest possible range of sin2ѱ using an Ω-goniometer. In order to measure the diffraction angle at very high sin η values, a scintillation counter was located on the -η side and an incident X-ray beam impinged on the ground surface with a very low angle from the +η side using the glancing incidence X-ray diffraction technique. A strong non-linearity was found in the 20-sin2ѱ diagrams especially at very high ѱ -angles. From the analysis of non-linearity, the stress distribution in the surface layer was determined. Tine residual stress took the maximum compression of 2 GPa at a depth of about 0.5 μm from the surface, and then diminished to zero at about 25 μm in depth. In the close vicinity of the ground surface, the compressive residual stress was relieved because of both the surface roughness and microcracking induced during the grinding process.

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Statistical analysis of the reproducibility of residual stress measurements in cold extruded parts

Archive of Applied Mechanics ◽

10.1007/s00419-021-01953-x ◽

2021 ◽

Author(s):

Fabian Jaeger ◽

Alessandro Franceschi ◽

Holger Hoche ◽

Peter Groche ◽

Matthias Oechsner

Keyword(s):

Residual Stress ◽

Statistical Analysis ◽

Stress Measurement ◽

Industrial Applications ◽

Cold Extrusion ◽

X Ray Diffraction ◽

Forming Process ◽

X Ray ◽

Stress States ◽

Key Aspects

AbstractCold extruded components are characterized by residual stresses, which originate from the experienced manufacturing process. For industrial applications, reproducibility and homogeneity of the final components are key aspects for an optimized quality control. Although striving to obtain identical deformation and surface conditions, fluctuation in the manufacturing parameters and contact shear conditions during the forming process may lead to variations of the spatial residual stress distribution in the final product. This could lead to a dependency of the residual stress measurement results on the relative axial and circumferential position on the sample. An attempt to examine this problem is made by the employment of design of experiments (DoE) methods. A statistical analysis of the residual stress results generated through X-Ray diffraction is performed. Additionally, the ability of cold extrusion processes to generate uniform stress states is analyzed on specimens of austenitic stainless steel 1.4404 and possible correlations with the pre-deformed condition are statistically examined. Moreover, the influence of the coating, consisting of oxalate and a MoS2 based lubricant, on the X-Ray diffraction measurements of the surface is investigated.

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