Integrity Evaluation of Composite Cylindrical Structures

2018 ◽  
Author(s):  
Jikai Du
Keyword(s):  
Residual Stress ◽  
Composite Material ◽  
Incident Angle ◽  
Composite Layer ◽  
Field Calculation ◽  
X Ray Diffraction ◽  
Cylindrical Structures ◽  
X Ray ◽  
Ultrasound Evaluation ◽  
Steel Layer

The application of composite material in structures can not only lower the component weight but also improve the system performance through its tailorable thermal and mechanical properties. However, because of the harsh environmental conditions that such structures may encounter during operation, the successful applications of such structures cannot be realized without appropriate techniques for their structural integrity evaluation. In this study, composite cylindrical structures consisting of composite and steel layers are being evaluated with X-ray diffraction technique and various ultrasound techniques. First, X-ray diffraction technique was applied for the quantitative determination of the residual stress in the steel layer. The influence of composite layer on the stress distribution was analyzed and how such residual stress study will improve the performance of the structure was discussed. Then various ultrasound techniques were applied for the detection of various defects, such as the defects at the surface and subsurface of inner steel layer, the different types of defects in the outer composite layer, and the defect, which is the most critical one, at the interface of steel/composite layer. During ultrasound evaluation, the composite material may not only increase the ultrasound attenuation but also change ultrasound traveling direction, and this can make the inspection more challenging. Theoretical calculations were carried out for the optimization of experimental parameters such as ultrasound frequency, incident angle, and focused ultrasound field calculation and so on. The limitations of ultrasound technique and the potential of other non-destructive techniques were also discussed according to experimental results.

Measurement of Residual Stresses in Thin Films by Two-Dimensional XRD

2006 ◽  
Vol 524-525 ◽  
pp. 613-618 ◽  
Author(s):  
Bob B. He
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Residual Stresses ◽  
Recent Progress ◽  
Stress Measurement ◽  
Incident Angle ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Stress Analysis

This paper introduces the recent progress in two-dimensional X-ray diffraction as well as its applications in residual stress analysis in thin films. The stress measurement with twodimensional x-ray diffraction can be done with low incident angle and is not limited to the peaks with high two-theta angles like the conventional method. When residual stresses of thin films are measured, a low incident angle is preferred to maximize the diffraction signals from the thin films surfaces instead of from the substrates and matrix materials. Since one stress measurement at one fixed incident angle is possible, stress gradients in depth can be measured by series of incident angles. Some experimental examples are given to show the stress measurement at low and fixed incident angle.

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

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.

Simulation and Experiment on the Residual Stress in Super-High Speed Grinding

2010 ◽  
Vol 135 ◽  
pp. 238-242
Author(s):  
Yue Ming Liu ◽  
Ya Dong Gong ◽  
Wei Ding ◽  
Ting Chao Han
Keyword(s):  
Residual Stress ◽  
High Speed ◽  
Element Model ◽  
Residual Stress Distribution ◽  
X Ray Diffraction ◽  
Machined Surface ◽  
X Ray ◽  
High Speed Grinding ◽  
Simulation And Experiment ◽  
Cylindrical Workpiece

In this paper, effective finite element model have been developed to simulation the plastic deformation cutting in the process for a single particle via the software of ABAQUS, observing the residual stress distribution in the machined surface, the experiment of grinding cylindrical workpiece has been brought in the test of super-high speed grinding, researching the residual stress under the machined surface by the method of X-ray diffraction, which can explore the different stresses from different super-high speed in actual, and help to analyze the means of reducing the residual stresses in theory.

Problems Associated with Kα Doublet in Residual Stress Measurements

1979 ◽  
Vol 23 ◽  
pp. 333-339
Author(s):  
S. K. Gupta ◽  
B. D. Cullity
Keyword(s):  
Residual Stress ◽  
Silicon Powder ◽  
Lattice Parameter ◽  
Diffraction Peak ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
The Difference ◽  
Similar Accuracy

Since the measurement of residual stress by X-ray diffraction techniques is dependent on the difference in angle of a diffraction peak maximum when the sample is examined consecutively with its surface at two different angles to the diffracting planes, it is important that these diffraction angles be obtained precisely, preferably with an accuracy of ± 0.01 deg. 2θ. Similar accuracy is desired in precise lattice parameter determination. In such measurements, it is imperative that the diffractometer be well-aligned. It is in the context of diffractometer alignment with the aid of a silicon powder standard free of residual stress that the diffraction peak analysis techniques described here have been developed, preparatory to residual stress determinations.

Service Loading Analysis of Wind Turbine Gearbox Rolling Bearings Based on X-Ray Diffraction Residual Stress Measurements

2013 ◽  
Vol 768-769 ◽  
pp. 723-732 ◽  
Author(s):  
Jürgen Gegner ◽  
Wolfgang Nierlich
Keyword(s):  
Residual Stress ◽  
Wind Turbine ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
X Ray Diffraction ◽  
Rolling Bearings ◽  
Wind Turbine Gearbox ◽  
X Ray ◽  
Stress Measurements

Rolling bearings in wind turbine gearboxes occasionally fail prematurely by so-called white etching cracks. The appearance of the damage indicates brittle spontaneous tensile stress induced surface cracking followed by corrosion fatigue driven crack growth. An X-ray diffraction based residual stress analysis reveals vibrations in service as the root cause. The occurrence of high local friction coefficients in the rolling contact is described by a tribological model. Depth profiles of the equivalent shear and normal stresses are compared with residual stress patterns and a relevant fracture strength, respectively. White etching crack failures are reproduced on a rolling contact fatigue test rig under increased mixed friction. Causative vibration loading is evident from residual stress measurements. Cold working compressive residual stresses are an effective countermeasure.

Revision and extension of the standard laboratory technique for X-ray diffraction measurement of residual stress gradients

2007 ◽  
Vol 40 (4) ◽  
pp. 675-683 ◽  
Author(s):  
Cristy L. Azanza Ricardo ◽  
Mirco D'Incau ◽  
Paolo Scardi
Keyword(s):  
Residual Stress ◽  
Hole Drilling ◽  
Al Alloy ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
X Ray ◽  
Stress Gradients ◽  
Layer Removal ◽  
Removal Technique

A new procedure is proposed to determine sub-surface residual stress gradients by laboratory X-ray diffraction measurements at different depths using a chemical layer-removal technique. The standard correction algorithm for stress relaxation due to layer removal is improved by including corrections for X-ray absorption, and by the addition of constraints imposed by the mechanical equilibrium conditions. Besides correcting the data,i.e.providing more reliable through-thickness residual stress trends, the proposed procedure also provides an elastically compatible and plausible estimate of the residual stress inside the component, well beyond the measured region. The application of the model is illustrated for a set of Al-alloy components shot-peened at different Almen intensities. Results are compared with those given by `blind hole drilling', which is an independent and partly destructive method.

Sign in / Sign up

Export Citation Format

Share Document