Hello every one,
An analysis of residual stresses on aluminum alloys is required. Is a new useful method available for evaluating the residual stresses on aluminum alloys?
Best,
As you knew the residual stress is a crucial factor when assessing the integrity of engineering components and welded assemblies. The contour method is widely used method to measure the residual stress in Alminumm alloys especially in my interest work in friction stir welding.
The contour method is a recent fully destructive residual stress measurement technique, developed by Prime in 2001. With this technique it is possible to determine residual stress state on a surface inside a body in the direction perpendicular to the cutting plane.
This technique has been used in a great variety of situations.
There are several articles discuss this method and how to use it in determining the residual stress such as:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://bibliotecadigital.ipb.pt/bitstream/10198/4047/1/FSW_contour_ECRS8.pdf&ved=0ahUKEwi0kpLr9fPYAhVR2qQKHWAqDCIQFgg3MAI&usg=AOvVaw3mAoL2lxIdX4z7cuLfeT6s
If you think this answer help you, please recommend it.
Thanks for your answer. It seems "the contour method" is a numerical method. I have some results of a residual test in our labs, and the analysis of the accuracy of the test data is required now. Some methods like power series are used, but they are old.
Best,
I´m sorry, but the analysis of residual stresses on polymer composites are not applied to the condition of your study.
The contour method is indeed an experimental method for measuring residual stress. See
http://www.lanl.gov/contour/
which includes two good examples on aluminum forgings.
Picking the best method for an application requires more information about the type of specimen you want to measure. For example, if you only need a through-thickness profile (1D, as compared to a 2D map), incremental slitting can work quite well, see this: http://www.lanl.gov/residual/alum.shtml
Depending on your needs, the are other methods that also might work well.
Dear Ali,
undoubtedly, the contour method is an established technique for residual stress measurements in metals, particularly suitable when the material undergoes to phase transformations (e.g. weldings). However, based on the same principle (stress relaxation) the ring-core/hole drilling method is a good alternative to obtain point measurements. Beside the well-known macroscopic version of this method, lately a considerable amount of effort has been put to pre-standardise the micro-scale version of it, based on Focused Ion Beam and Digital Image Correlation (FIB-DIC). An example of this technique applied to Aluminium Alloys can be found here: Chapter Residual Stress Measurement on Shot Peened Samples Using FIB-DIC
Anyway, as Michael Prime correctly pointed out, knowledge about type of sample is very important when choosing the most suitable method.
Enrico
Thanks for your answers.
I have extracted a residual stresses of an aluminum part and used the hole-drilling method. Now, I need to verify the residual stresses extracted by hole-drilling method. Is a new method (numerical method) available to examine the residual stress test results?
Best,
Dear Ali,
have you come across the Integral method? This is a widely accepted method for the back calculation of residual stresses when the ring-core method is employed.
Enrico
Dear Enrico,
Thanks for your response. I have used the Integral method, but I am looking for a newer method which is used recently.
Best,
Dear Ali,
if you are looking for something new, well I suggest you to be a little patient. Our research group is actively working on the development of a novel method for the reconstruction of residual stress from the ring-core strain relief curve. Such method will no longer require the use of FEM simulations for the calculation of the matrix coefficients since the sensitivity functions will be provided in the manuscript, which will be valid for the larger majority of problems. Hopefully this work will be released in the next few weeks. I can keep you posted if interested.
Regards,
Enrico
Dear Enrico,
Sure! Please let me know! Thanks in advance!
Best,
Ali
Dear Ali,
as promised, here is the method we recently developed for the evaluation of residual stress depth profiles using the FIB-DIC micro ring-core method:
Article Nanoscale residual stress depth profiling by Focused Ion Bea...
The great advantage of this method is that the calibrated sensitivity functions provided are independent from the milling step size and core diameter. The method can be even used for the macroscopic version of the ring-core technique, provided that Digital Image Correlation (DIC) is employed for monitoring the deformation taking place on the core surface.
However, in case you wish to use classic strain gauges, then you will need to perform a FEM simulation to obtain the specific sensitivity function for this configuration.
Hope this helps.
Regards,
Enrico
I recommend to try X-rays diffraction side-inclination method. You need to know elastic properties of the examined material. Performing a series of XRD tests at near-representative peak 2 Theta zone through sample's tilt, you obtain peak shift vs tilt angle. Using this data (line slope) together with the elastic constants, you can simply calculate a residual stress in your material. If you need a detail description of the method, I can send you.
Dear Alexander,
Thanks for your answer. please let me know more about the details whenever you feel free.
Best,
Ali
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