Font Size: a A A

Research Of Data Processing And Nano-indentation Residual Stress In Raman Mechanical Experiments

Posted on:2015-09-16Degree:MasterType:Thesis
Country:ChinaCandidate:Y T HanFull Text:PDF
GTID:2311330485493671Subject:Solid mechanics
Abstract/Summary:PDF Full Text Request
In recent years, with the rapid development of science and technology in the field of micro-nano, it has become an issue of growing concern for how to accurately measure the mechanical properties of materials and structures in the micro-nano scale. However, the testing techniques of macroscopic field can always hardly meet the test requirement, so it is necessary to explore new testing methods and techniques. The mechanical measurement technique using Micro-Raman Spectroscopy is developed in recent years, it has many advantages such as non-contact, high sensitivity, high spatial resolution(?1?m), and real-time on-line measurement, so it has the development potential in the field of micro-nano experimental mechanics. This method based on the Raman spectrum information obtained from experiments for mechanical measurements, is quite sensitive to peak position of Raman characteristic peak, so a systemic research to the influence of peak fitting by noises is an important foundation in Raman mechanical measurement.Firstly, in this study the effects on peak fitting by random noise, baseline and sharp peak is studied. By the means of numerical simulation, it is found that the effect of random noise is relative to noise level, FWHM and spectral resolution; if we assume that the form of baseline is linear, then the effect of baseline can be characterized by the specific value of the slope of baseline and the intensity of the peak; the effect of sharp peak is related to its intensity and relative position to Raman characteristic peak position.Secondly, according to the characteristics of three kinds of different noise, this study did research on how to improve the accuracy of peak fitting. With respect to random noise, the effects on peak fitting of four typical filtering methods are analyzed, and discussed the effect of filtering on the accuracy of peak fitting; in regard to baseline, a method called baseline fitting is proposed to eliminate the effects of baseline, and the effect of which is analyzed then, the outcome revealed that this method did make a difference; a suggested method is proposed to deal with sharp peak according to its characteristic.At last, this study conducted a study on the distribution of residual stress on loaded monocrystalline silicon, measured and gave the residual stress fields around the indentations of two kinds of different crystal orientation monocrystalline silicon which are loaded by a Bercovitch indenter by using Raman spectroscopy scan imaging technique, discussed the zone size around the indentation influenced by residual stress, gave the numerical value of residual stress near the edge of the indentation quantitatively, Besides, the effect of different crystal orientation on residual deformation was analyzed, as well as FWHM, peak intensity and other experimental information. This work indicates that Raman spectroscopy technique is an effective method in residual stress experimental measurement.
Keywords/Search Tags:Micro-Raman Spectroscopy, Numerical Simulation, Peak Fitting, Monocrystalline Silicon, Residual Stress
PDF Full Text Request
Related items