Literature Review vs. Literature Survey

Many a time, a student does not really understand if there is a difference between a 'literature review' and a 'literature survey'.
Now, is there a difference? YES there is!
Then, what is the difference?
In a survey, you show the fact that a work exists published/unpublished in the past. One does not read in detail and discuss about it in the case of a survey. So we collect the documents, sort and compiles them and give a survey report.
In a review, one would read the facts in a document referred and discusses about it. He/she tends to connect the facts and join the dots to tell the reader a story. That story would have a flow which takes you to the purpose of the review and tells you what exactly was done in the history/background, why and how was that done and the output in brief.

Having said that, you need to be sure when you are doing a literature search. Be sure if you are making a survey.. or a proper review!

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Are our Stress & Strain calculations reliable?

It has been taught that Load and deflection across specimens can vary. But not the stress and strain. True! And that is why while characterizing /testing a material, we express load and deflection in terms of stress and strain for the convenience of comparison and standardization.

BUT what one should realize is that the stress and strain are user dependent parameters in real time tests. You are inputting area A and gauge length GL for stress and strain respectively. Have you thought of the variation in stress or strain, per unit error in the area or length that you are calculating?

What Gauge Length is to be taken for a typical tensile test?

Gauge Length (GL) is basically the length of interest for which one measures the deflection during a standard tensile test. As the name suggests, you 'gauge' the ength of your interest for the study being conducted.

Several standards give specifications for the GL to be considered for these tests. What has been observed in American codes is a standard length of 5D where D is the diameter of the steel rod tested. IS code defines it as 5.65*sqrt(A) where A is the Area of cross section of steel. But if you substitute A in terms od D as pi*D*D/4, it turns out to be same as 5xD.

So why can't we take a longer or shorter GL?
Too long a GL?
Your strain is going to be averaged if you increase your GL. So you need to be sure that the length you are considering is enough to e the influential length of plastic deformation (In elastic region, nothing to worry about as we assume all the whole bar to deform at the same strain rate. But note that that the strain% is very low at the elastic limit which is typically 0.2% compared to the ultimate strains of 16-20% or more)

Too less a GL?
Well, you need to make sure that you are not focusing in too much in the complex stress area. You need to have a distance wherein the the stress flow becomes uniform, for which distance it is standardized to be considered for tensile test. It was 4xD initially which was revised to 5xD(Said to be based on test results by the Standardization Agency)

Is TMT same as QST?

TMT or 'Thermo Mechanical Treatment' is a generic term. There are several manufacturing processes under TMT which produces different varieties of steel (Islam 2010). One of the different varieties is called QST or 'Quenched and Self-Tempered' steel, which is used under the misnomer of TMT in India. It is special with having an outer hard 'tempered-martensite' layer and an inner ductile 'ferrite-pearlite' layer as shown in the figure.It is important to know the right terminology and avoid confusion in this regard. Currently in India, the one which we call TMT is none other than QST.