Measurement of residual stress using fiber electronic speckle pattern interferometry

Author(s):  
Jingbo Zhang ◽  
Wing C. Fok ◽  
Tow Chong Chong
2013 ◽  
Vol 768-769 ◽  
pp. 79-86 ◽  
Author(s):  
Horst Brünnet ◽  
Dirk Bähre ◽  
Theo J. Rickert ◽  
Dominik Dapprich

The incremental hole-drilling method is a well-known mechanical measurement procedure for the analysis of residual stresses. The newly developed PRISM® technology by Stresstech Group measures stress relaxation optically using electronic speckle pattern interferometry (ESPI). In case of autofrettaged components, the large amount of compressive residual stresses and the radius of the pressurized bores can be challenging for the measurement system. This research discusses the applicability of the measurement principle for autofrettaged cylinders made of steel AISI 4140. The residual stresses are measured after AF and after subsequent boring and reaming. The experimental residual stress depth profiles are compared to numerically acquired results from a finite element analysis (FEA) with the software code ABAQUS. Sample preparation will be considered as the parts have to be sectioned in half in order to access the measurement position. Following this, the influence of the boring and reaming operation on the final residual stress distribution as well as the accuracy of the presented measurement setup will be discussed. Finally, the usability of the FEA method in early design stages is discussed in order to predict the final residual stress distribution after AF and a following post-machining operation.


2017 ◽  
Vol 890 ◽  
pp. 344-347 ◽  
Author(s):  
Mohamed Ackiel Mohamed ◽  
Yupiter H.P. Manurung ◽  
Markus Laakkonen

Tensile residual stress in friction stir welded (FSW) Aluminum alloy joints is well known to be detrimental to fatigue resistance properties of joints imperiled to dynamic loading. Hence, it is important to translate the prevailing tensile residual stress to a more favorable compressive residual stress to enhance the fatigue life cycle of the welded joints. In this study, the longitudinal and transverse residual stress for FSW AA 6061 joints is measured using the hole-drilling method with electronic speckle pattern interferometry (ESPI) for various conditions. This method combines the tried-and-true hole-drilling method with digital imaging and ESPI, eliminating the application of a strain gage through stress depth profile measurements by incremental drilling. The residual stress is measured for the FSW as-welded and high frequency mechanical impact/pneumatic impact treatment (HFMI/PIT)-treated conditions.


2002 ◽  
Vol 750 ◽  
Author(s):  
Dong-Won Kim ◽  
Nak-Kyu Lee ◽  
Kyung-Hoan Na ◽  
Dongil Kwon

ABSTRACTBased on the identification of the residual stress-free state using electronic speckle pattern interferometry (ESPI), we modeled the relaxed stress in annealing, the thermal strain/stress and the residual stress field in case of both single and film/substrate systems by using the thermo-elastic theory and the relationship between relaxed stresses and displacements. Thus we mapped the surface residual stress fields on the indented bulk Cu and the 0.5μm Au film by ESPI. In indented Cu, the normal and shear residual stress are distributed over -800 MPa to 700 MPa and -600 MPa to 600 MPa respectively around the indented point and in deposited Au film on Si wafer, the tensile residual stress is uniformly distributed on the Au film from 500 MPa to 800 MPa. Also we measured the residual stress by the x-ray diffractometer (XRD) for the verification of above residual stress results by ESPI.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Claudia Barile ◽  
Caterina Casavola ◽  
Giovanni Pappalettera ◽  
Carmine Pappalettere

Hole drilling is the most widespread method for measuring residual stress. It is based on the principle that drilling a hole in the material causes a local stress relaxation; the initial residual stress can be calculated by measuring strain in correspondence with each drill depth. Recently optical techniques were introduced to measure strain; in this case, the accuracy of the final results depends, among other factors, on the proper choice of the area of analysis. Deformations are in fact analyzed within an annulus determined by two parameters: the internal and the external radius. In this paper, the influence of the choice of the area of analysis was analysed. A known stress field was introduced on a Ti grade 5 sample and then the stress was measured in correspondence with different values of the internal and the external radius of analysis; results were finally compared with the expected theoretical value.


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