Radiation Heat Transfer

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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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Shear In Beams

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Introduction To Structural OR Concrete Design

Beams must have adequate strength against different types of failure which are:
  • Shear more dangerous than Flexural (or Bending) failure because it creates additional tensile stresses.
  • E.g.: Airplane wing (act as cantilever beam) and made of Nanocomposites, composites, aluminum.
Following are the types of failures in Beam:
  1. Longitudinal Shear
  2. Transverse Shear

Shear Failure

  • Diagonal Tension Failure  ↠  Shear failure of reinforced concrete beam (difficult to predict).
  • Only valid for Homogenous beams.
  • When we apply load on beam  ↠  Bending as well as Shear stresses are produced.
  • Shear stress have maximum value at Neutral axis N.A.
  • Bending stress have maximum value at Extreme fibers.
  • At maximum bending stress  ↠  shear stress = 0.
Assumptions for shear stresses in beams are:
  • Shear stress is constant across the width of the cross-section (for Rectangular cross-section).
  • It is aligned with Y-axis.
Shear in I-Beams
  • 2-Flanges  ↠  Bending Resistant
  • Web  ↠  Shear Resistant

Shear Flow in Built-Up Members

Build-up Members are defined as, "members or geometries which are made by joining two parts by glue, nails or rivets".
  • Made from several composites parts to achieve a greater resistance to loads.
  • Shear Flow 'q'  ↠  Shear force per unit length.

References:

  • Material from Class Lectures + Book named Engineering Mechanics of Materials by R.C. Hibbeler (6/9th Edition) + my knowledge. 
  • Pics and GIF from Google Images.  
  • Videos from YouTube (Engineering Sights).

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