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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Frames and Machines
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Truss and it's Types:
Truss is a structure of connected elements forming triangular units, and a bridge whose load-bearing superstructure is composed of a truss.
There are three types of truss and they are:
1. Simple Truss:
A truss is a structure composed of slender members joined together at their end points.
2. Planar Truss:
Planar truss lies in single plane and typically used in parallel to form roofs and bridges.
3. Space Truss:
A space Truss consists of members joined together at their ends to form a stable three-dimensional structure.
Assumptions for Designing Truss:
To design the truss, we have two assumptions:
All loadings are applied at the joints.
The members are joined by smooth pins.
The Method of Joints:
In order to analyze or design a truss, it is necessary to determine the forces in each of its members. Method of joints consists of fool owing steps:
Truss is in equilibrium so does its joints.
Draw Free-body diagrams for each joint.
Apply the force equilibrium equations and obtain the required ones.
ΣFx = 0
ΣFy = 0
The Method of Sections:
By using the method of sections, you need to follow the instructions below:
Truss is in equilibrium so does the segments of truss.
Draw free Body diagram indicating all forces.
Cut the free Body diagram into its simple parts.
Apply the equilibrium equations to find the required forces and moments.
ΣFx = 0
ΣFy = 0
ΣMo = 0
Zero Force Members:
Zero-force members in a truss members which do not have any force in them. Zero-force members are used to increase the stability of the truss during construction and to provide added support of the loading is changed.
Frames:
Frames used to support loads which are often composed of pin-connected multi-force members that are subjected to more than two forces.
Machines:
Machines contain moving parts which are often composed of pin-connected multi-force members that are subjected to more than two forces.
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: Flexural (or bending) failure Diagonal Tension failure Shear-Tension failure Shear-Compression failure Following are the types of Shear : Longitudinal Shear 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 i...
Strain Energy or Resilence It is defined as, " energy absorbed in a body when deformation is done on material " . Depend on Material . Strain Energy Density is defined as, " strain energy per unit volume " . Independent of material . Used to tell which deformation component is greater with direction. If greater in specific direction ↔ crack propagates in that direction. Stress (in Dynamic effect) > Stress (in Static effect) Types of Loading Energy Conservation It states that, " Energy can neither be created nor be destroyed but can transfer in other forms " . We only deal with mechanical energy. External work = internal energy or strain energy . If this external force is in elastic limit, strain energy restores body back to its original undeformed position. Note: For Castigliano's Theorem ↔ See Energy Method . With the application of force on Car chassis , How it behaves? References: Material from Class Lectures + Book named Engineering Mec...
Gear Generation by Machining Tooth profile is provided by much simpler form cutting tool through hobbing, gear shaping. It involves the following methods: Gear Hobbing Gear Shaping 1. Gear Hobbing It is defined as, " a machining process in which gear teeth are progressively generated by a series of cuts with a helical cutting tool " . Most accurate machining process. Used for gears production because it has excellent surface finish. Continuous Indexing Process ↠ in which both cutting tool and workpiece rotate in constant relationship while hob is being fed into work. Feed Directions The direction of feed during hobbing operation depends upon the type of gear to be cut. Following are the types of feed directions: Axial Feeding ↠ cutting spur and helical gears (Hob axis is parallel to Blank axis). Radial Feeding ↠ for bevel gears (Hob axis is perpendicular to Blank axis). Tangential Feeding ↠ for worm, straight, spiral...
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