Use of Full Field of Strains Found By Grating Shearography to Determine Residual Stress

2005 ◽  
Vol 40 (7) ◽  
pp. 621-630 ◽  
Author(s):  
G Montay ◽  
J Bulhak ◽  
Y Surrel ◽  
A Vautrin ◽  
J Lu
Keyword(s):  
Residual Stress ◽  
Strain Field ◽  
Hole Drilling ◽  
The Finite Element Method ◽  
Full Field ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Drilling Method ◽  
Very High Spatial Resolution ◽  
High Level

A new method combining grating shearography and the incremental hole drilling method has been developed to determine the residual stress distribution in depth. Grating shearography is a technique designed to determine directly the strain field with a high level of sensitivity and a very high spatial resolution. The hole drilling method is one of the most popular methods used in mechanical engineering to determine the residual stress locked into a structure. This new optical method enables the strain to be measured while taking into account the entire strain field around the hole. The finite element method is used to calibrate the method. The method was tested on an ultrasonic shot-peened aluminium specimen.

Dependence Between Aging Treatments and Residual Stresses on Composite Laminate

2006 ◽  
Vol 524-525 ◽  
pp. 813-817 ◽  
Author(s):  
Olivier Sicot ◽  
X.L. Gong ◽  
Xiao Jing Gong ◽  
Abel Cherouat ◽  
Jian Lu
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Composite Structures ◽  
Hole Drilling ◽  
The Finite Element Method ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Drilling Method ◽  
Initial Cycle ◽  
Calibration Coefficients

The objective of this paper is to study the influence of residual stresses due to fabrication conditions on the thermomechanical behavior of carbon/epoxy laminate structures (cross ply). These studied laminates have undergone various cycles of thermal aging. The addition of a post-cure cycle after the end of the initial cycle makes it possible to reduce the residual stresses level. The incremental hole-drilling method is used to measure the residual strain in the laminates. These measured strains and the numerical calibration coefficients obtained by the finite element method allow to calculating the residual stress distribution in composite depth. The obtained results show that heat treatments of composite structures do not lead to an important reduction the initial residual stress due the fabrication conditions.

scholarly journals Incremental Hole-Drilling Method Vs. Thin Components: A Simple Correction Approach

2014 ◽  
Vol 996 ◽  
pp. 283-288 ◽  
Author(s):  
Esther Held ◽  
Simone Schuster ◽  
Jens Gibmeier
Keyword(s):  
Residual Stress ◽  
Thin Metal ◽  
Hole Drilling ◽  
Depth Profiles ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Metal Sheets ◽  
Drilling Method ◽  
Measured Strain ◽  
The Impact

The incremental hole-drilling method is a widely used technique to determine residual stress depth profiles in technical components. Its application is limited in respect to the components geometry, for instance the components thickness. In this paper, a direct correction of the measured strain relaxations is proposed to consider the impact of deviant geometries, here the component thickness, on the residual stress evaluation that moreover, allows the application of commercially available evaluation software. The herein proposed approach is based on finite element simulation of the incremental hole drilling. The simulated strain relaxations for thin metal sheets are evaluated with an algorithm as used in commercially available evaluation software (i) for uncorrected data as well as (ii) for strain data corrected by the proposed correction procedure. It is shown that the correction approach leads to a significant improvement of the measurement accuracy. Further, by means of the approach residual stress depth profiles in thin metal sheets can be as usual determined using commercial evaluation software for the incremental hole-drilling method regardless of the algorithm used, i.e. differential or integral.

Potentialities of Ultrasonics for Evaluating Residual Stresses: Influence of Microstructure

2002 ◽  
Vol 124 (3) ◽  
pp. 349-353 ◽  
Author(s):  
H. Walaszek ◽  
H. P. Lieurade ◽  
C. Peyrac ◽  
J. Hoblos ◽  
J. Rivenez
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Ultrasonic Method ◽  
Thermal Relaxation ◽  
Good Control ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Drilling Method ◽  
Ultrasonic Measurements

The good control of residual stress level in mechanical components is an important factor, particularly for a good fatigue strength of these components. This paper presents advances obtained at the technical center for mechanical engineering industries (CETIM) in the field of development of an ultrasonic method for stress measurements. This method is potentially advantageous because it is nondestructive, has good portability, and is easy to use. In the paper are discussed the results obtained with ultrasonics on steel welded plate, and a comparison is made with stress measurement obtained by incremental hole-drilling method, and X-ray diffraction. These results are also validated by thermal relaxation of the plates. The paper discusses also the microstructure influence on ultrasonic measurements and methods for adjusting the ultrasonic measurements to improve the agreement with results obtained from other techniques. In conclusion is emphasized the interest for studying the ability of the ultrasonic residual stress measurement method in different industrial cases.

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