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Measurements of surface stress evolution
We recently have reported first measurements of surface stress evolution in a material as a function of uniaxial time dependent deformation and at temperatures upto 100 degree C using a new analytical technology, Nanomechanical Raman Spectroscopy developed in our lab (Interfacial Multiphysics Lab directed by Dr. Vikas Tomar at Purdue).
In particular, we wanted to bring to your attention the following publications:
Surface stress evolution during microscale uniaxial creep/time dependent low stress deformation as a function of temperature upto 100 degree-C (see esp. Fig. 8)
http://nanoengineeringmedical.asmedigitalcollection.asme.org/article.aspx?articleID=1899465
Breakup of Raman Signal into stress and temperature signals during in-situ deformation to predict stress and thermal properties at material surfaces simultaneously as a function of in-situ applied deformation
http://scitation.aip.org/content/aip/journal/rsi/85/1/10.1063/1.4861201
Comparing Applied stress with elastic stress and surface stress (MEMS based techniques for measuring applied stress consider the applied stress the same as stress calculated based on elastic constants..What we show is that high temperatures this assumption needs to be checked). It is shown that as temperature increases surface stress deviates significantly from applied stress which also differs from stress calculated from elastic constants (albeit slightly). (see Fig. 7) We also give an expression for stress variation as a function depth/distance from surface.
http://scitation.aip.org/content/aip/journal/jap/116/7/10.1063/1.4892623
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