View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge. Photoshoped pics are developed. Some pics and GIF from Google. Videos from YouTube ( Engineering Sights ).
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Advance High Strength Steel (AHSS)
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Advance High Strength Steel
Conventional low carbon mild steel has simpler ferritic structure (α-iron) and good ductility.
Common type of HSS is High Strength Low Alloy (HSLA) ⇥ has yield strength 550 - 690 N/sq.mm.
Manganese ⇥ supporter (stabilizer) of ferrite.
Conventional HSS:
Is single-phase ferritic steel with a potential for some pearlite in C-Mn steel.
Lower strain hardening capacity.
Advance HSS:
primarily steel with a microstructure containing a phase other than ferrite, pearlite, cementite.
Crumple Zone ⇥ Made with those materials which absorb maximum amount of energy.
Safety Cage ⇥ Multiple areas (like cabins, structural elements).
Areas of Safety cage are described ahead:
Cabins (Blue Areas) ⇥ Should have high strength with a good balance of strength, formability, energy absorption and durability.
Structural Elements (Red Areas) ⇥ Safety critical parts.
Conclusion is:
Dual phase (DP) & Transformation induced plasticity (TRIP) steels are excellent in crash zone (high energy absorption capacity), so it is used to make Crumple Zone.
For structural elements ⇥ Extremely high strength steels such as Martensite and Boron-based Press Hardened (PHS) steels are used.
Advance HSS Family
Dual Phase (DP)
Complex Phase (CP)
Ferritic Bainitic (FB)
Martensite
Transformation Induced Plasticity (TRIP)
Hot Formed (HF)
Twinning Induced Plasticity (TWIP)
Dual Phase (DP) Steel
It consist of a ferritic matrix containing a hard martensite second phase in the form of island.
Microstructure is produced by giving steel a Sub-Critical Anneal at 800℃ and is quenched to room temperature.
Sub-Critical Anneal ⇥ Heating a material (steel) lower than the equilibrium line between austenite and α-phase and then cool it.
Ferrite is unaffected by heat treatment but Austenite grains transformed to martensite during quenching and is tempered at low temperature to increase ductility.
Tempering ⇥ heat treatment process that is performed in steels containing martensite just to relief some stresses.
DP Steel exhibits high work hardening rate, ultimate tensile strength, Tensile & Yield strength ratio.
Transformation Induced Plasticity (TRIP) Steel
It consist of Austenite embedded in a primary matrix of ferrite.
To get retained austenite ⇥ use Step Quenching (from Transformation Time VS Transformation Temperature Graph)
TRIP steel has lower initial work hardening rate than DP.
It uses higher quantities of carbon than DP to obtain sufficient carbon content for stabilizing the retained austenite phase to below ambient temperature.
Si & Al ⇥ used to avoid carbide precipitation in the bainite region.
Projection: The term Projection is defined as: Presentation of an image or an object on a surface. The principles used to graphically represent 3-D objects and structures on 2-D media and it based on two variables: Line of Sight. Plane of Projection. Line of Sight & Plane of Projection: Line of sight is divided into 2 types: Parallel Projection Converging Projection & A plane of projection is an imaginary flat plane upon which the image created by the lines of sight is projected. Orthographic Projection: When the projectors are parallel to each other and perpendicular to the plane of projection. The lines pf sight of the observer create a view on the screen. The screen is referred to as the Plane of Projection (POP). The lines of sight are called Projection lines or projectors. Rules of Orthographic Projection: Edges that are parallel to a plane of projection appear as lines. Edges that are incl...
Angles & Directions Angles are also called bearings. Bearings are the acute angles between lines and meridians. They are divided into following types. Related Terms : Meridian : Imaginary line joining North and South poles. Declination : Difference between magnetic and true meridians. Azimuth : Clockwise angle taken from Geodatic North. * If area is greater ➤ use Geodatic North * If area is smaller ➤ use Magnetic North Magnetic Declination maybe towards East or West. For east ➤ Magnetic bearing=true bearing - Declination For west ➤ Magnetic bearing=true bearing + Declination Forward Bearing : Bearing taken in the direction of traverse. Backward Bearing : Bearing taken in opposite direction of traverse. Forward bearing - Backward bearing=180 For anti-clockwise : FB of line = BB of previous line + angle Example: In an anti-clockwise traverse <A=102'30',...
Pressure: Pressure is defined as: ' Normal force per unit area of body'. There are different pressures which we described ahead: Atmospheric Pressure ⟺ Pressure exerted by atmosphere. Absolute Pressure ⟺ The actual pressure at a given point. It is calculated with respect to absolute zero pressure. Gage Pressure ⟺ It is difference between the absolute pressure and the local atmospheric pressure. Vacuum Pressure ⟺ Pressure below atmospheric pressure. Pressure At A Point In A Fluid: For the pressure at a point in fluid, consider a triangular area of fluid. Consider a free body diagram with in a fluid mass. The force and weight components along Z-axis is given by: So, pressure at a point of a fluid at rest or motion is independent of direction as long as there are no shearing stresses present. Types Of Forces: There are two types of forces which are described ahead: Body Forces ⟺...
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