What is "BINGE WATCHING"?

            Binge watching is when you get so addicted to a TV series(or web series) that you stop caring about the rest of the world, leave all your problems and worries behind and start watching it even when the tingly feeling in your gut keeps telling you "I have deadlines to meet, I should not be doing this". You say to yourself, "this is the last episode I am going to watch today", but, you start watching the next episode before your gut tells you otherwise.

              For example, when I started watching Game of Thrones, four seasons were already out and I started watching just because I was bored and had nothing else to do. Once I watched the first episode of the first season, I was hooked onto it like a monkey on a branch. I finished four seasons in two days. That s about fifteen hours of watching in a day.

             Here is a meme I found on binge watching.

            Lately, I have realised this also happens with random YouTube videos. The suggestion algorithm is so good(It's a bitch actually) that you end up watching totally unconnected videos until your battery runs out or your data cap is reached. If you have broadband and are connected to the mains, GOD SAVE YOU!!!

What is theory of elasticity? What is the physical meaning of theory of elasticity?

    Why study theory of elasticity before FEM? Well, because all of the major universities have it as the first chapter or at least as a part of the first unit of their FEM course plan. But, why is that so? Well, keep reading to know.

Consider mild steel. We have all performed the infamous destructive test to determine the yield strength of mild steel. That was a fun experiment. Now consider this, if in case you had not loaded up to the ultimate stress, or until the yield stress and just loaded the test piece until the stress Vs strain graph stayed in the linear region. What would happen then? The experiment definitely would not have been fun but if you observed the material carefully, the extended test piece after removing the load, would come back to its initial length. This is known as ELASTIC behaviour. So, guess what theory of elasticity deals with... yeah right it’s about the behaviour of bodies within the elastic range.

The theory of elasticity assumes that the bodies are perfectly elastic along with this there are a few other assumptions. They are:

·   Molecular Structure: The molecular structure of bodies will not be considered here. It will be assumed that matter is homogeneous and continuously distributed over its volume. Hence if you cut out a chunk out of the body, it will have the same physical properties as that of the remaining body.

·  Isotropic: it is assumed that the molecular structure is the same in all the directions.

These assumptions are not really accurate for real world materials (E.g.: consider steel, the properties of steel far away from being homogenous when studied at the microscopic level.) but there is proof that the values obtained from this theory and that from the experiment are in agreement. So the results depend on the size of the chunk that you take. If it has micro dimensions, the theory will not hold good.

What are the forces acting on the element? There are two kinds, body forces and surface forces body forces are the one which act on the volume say the forces of gravity acting on your body right now. Surface forces could be the air pressure acting on the surface of your skin.

This is how surface forces and stresses are denoted. The letter σ_a denotes normal stresses parallel to the coordinate axes where a is the direction of the coordinate axis it is acting along. Similarly, τ_ab denotes shear stresses acting on a surface where a is the surface the shear force is perpendicular to and b is the direction the force is parallel to. I feel it is the easiest way to remember. The directions shown in the image are taken as positive. If the forces act in the opposite direction, the sign changes.

Let us consider strain,

I have this cube and let us say it is not free to move around (stuck to the table with superglue) but, it is free to deform when force is applied. Now the displacement of the particles are resolved into u, v, and w which are parallel to the axes x, y and z, respectively. Since I have a cube of dimensions dx, dy and dz as shown in the figure, the displacement would be something like this (in 2D) you just have to have a look at the diagram to get the idea. Totally self-explanatory.

Let us use the letter ϵ for strains that are parallel to the coordinate axes and ϒ for shear strains,(i.e. the ones that are parallel to the surface of the body). Determining the directions of strains parallel to the coordinate axes is easy as there is only one subscript (like ϵ_x or ϵ­­_y or ϵ_z) and the shear strains have the same naming pattern as that of the shear stresses. So now we know what theory of elasticity is, the notations used to denote stresses, strains and the directions. In my next post, I will complete the basic equilibrium equations involved in the theory of elasticity.

 References:

Theory of elasticity-Timoshenko & J.N. Goodier

Almost finished my B.E....YAY!!!

Now that I am almost a mechanical engineer, I am going to have a break of about two months after I finish my finals and join my company. This I feel is a good time to start understanding stuff that I hadn't understood while I was doing my course and study new softwares. I am planning on starting with NX, Ansys and do some physical understanding of maths(especially Diff. Eqn's(ya I kno, that bitch ryt, but it is soooo important)). While on it, I will be making tutorial videos on all of it so others can benefit from it too. So stay tuned. 

cheers!!!

"Money Isn't Everything", "Try to enjoy the little things in life"- who really says this stuff???

Don't ever say these things.

• Money is one of the most important things in life. Of course, it can't buy you happiness but without money, you are as good as dead in this ruthless world. If you cannot feed yourself you will either end up as someone pet animal ie., have no self-respect, will be tossed around like an object. Maybe if you are lucky you will end up like Stuart from the Big Bang Theory.
• Little things in life?What are little things in life? in the french movie "Amelie", by little things in life she refers to sinking her hands in a drum full of rice at the grocery store etc., but if you analyse Amelie's life in greater detail you draw a conclusion that she had not accomplished anything in life, so the little things in life could just be a cover up for not tasting success. Not just her, I have observed (and will add examples when I come across) everyone who says such stuff is in a pathetic state.

Work hard stay blessed and don't say such nonsense. have some achievements of your own that you are proud of.

Thanks for reading and comment what you think

What is a VTOL???

     A VTOL is an aircraft that can takeoff or land vertically ie.,WITHOUT A RUNWAY!!! just like a helicopter. But, it is still an airplane. Common examples include the Harrier Jumpjet, The Lockheed F32 Lightening II. 

     Recently, I watched Deadpool (I know its about a year old now, I am Late) and while I was doing so, I came across something really funny. See that here( https://youtu.be/dXq-zKq8YDk ). 

Now, the SR-71 Blackbird is a supersonic aircraft with a top speed of Mach 3.2 (That is 3.2 times the speed of sound!!!). It is a legendary aircraft with a TurboRamjet Engine and, it is my Favourite Aircraft. But It really Cannot do that...:(...

What is vapour pressure, partial pressure? what is boiling? evaporation?

      Vapour pressure and partial pressure is a beautiful concept and need a bit f clarity while studying psychrometry in thermodynamics. I just fond a beautiful explanation on the net which i thought was worth sharing.
Follow the link - Click Here!!!

What is exhaust gas dilution?

Exhaust gas dilution is something I did not find an elaborate explanation for on the internet so here goes.

                In a naturally aspirated I.C. Engine, there are basically three ranges of operation:

1.       Idling Range

2.       Cruising Range

3.       Power Range

Exhaust gas dilution mainly occurs during idling and is insignificant during the other two ranges. The pressure distribution in the Inlet manifold, Exhaust manifold and Cylinder head while idling is given in the diagram below. We see that the pressure at the inlet manifold is very low when compared to the other two regions. This occurs due to the closed throttle.

Case 1: When fresh charge is admitted into the cylinder while idling, the quantity of fresh charge is quite less when compared to the charge admitted while throttling. The fresh charge and the exhaust gas in the cylinder mix up to reduce the air fuel ratio significantly. This results in poor combustion and as a result, a loss of power.

Case 2: With Nearly closed throttle, the pressre in the intake manifold is significantly less when compared to the other regions. The pressure differential causes a backward flow of exhaust gasses into the intake manifold as soon as the inlet valve opens. When the piston moves down, sucking the charge, the charge is already diluted with the exhaust gasses leading to poor combustion.

Case 1 and 2 both act together to dilute the intake charge to an extent where the engine stalls and shuts down.

This can be avoided by sending a richer mixture into the cylinder such that the air-fuel ratio stays within the combustible range even after dilution.
Image is from the book Internal Combustion Engines(2nd Edition)-V. Ganesan