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 ).
Get link
Facebook
X
Pinterest
Email
Other Apps
Equilibrium of a Particle and Force System Resultants
Get link
Facebook
X
Pinterest
Email
Other Apps
-
Equilibrium of a Particle
Equilibrium:
A particle is said to be in equilibrium if it remains at rest or moving with constant velocity and does not rotate about any axis.
This condition of rest or moving with constant velocity is also called Static Equilibrium.
Coplanar Force Systems:
If a particle is subjected to a system of coplanar forces that lie in the x-y plane then every forces can be resolved into its components.
Since, it is 2D so the equilibrium equations are:
Σ Fx = 0
Σ Fy = 0
3D Force System:
In case of three-dimensional force system, we can resolve the forces into their respective rectangular components.
So the equations of equilibrium are:
Σ Fx = 0
Σ Fy = 0
Σ Fz = 0
Force System Resultants
When a force is applied to a body it will produce a tendency of rotation of body about a point which us not on the line of action of force.
Moment of a Force (Scalar Formulation):
In this sense, the momen is considered as scalar and us calculated as:
Moment = (Force) × (Moment Arm)
M = Fd
Cross Product Formulation of Moment of A Force:
The moment of a force will be formulated using Cartesian vectors is given by:
Principle of Moment:
Principle of moment or Varignon's Theorem states that:
The moment of a force about a point is equal to the sum of the moments of the components of the force about that point.
This method is generally easier than finding the same moment using M = Fd.
Moment of a Force about a Specified Axis:
To determine the turning effect of a force, we can use scalar or vector analysis.
1. Scalar Analysis:
By using the scalar analysis of Turning effect of a force, we have:
M = Fd
2. Vector Analysis:
The vector analysis of moment of a force about an axis is given by:
Couple:
It is defined as:
Two parallel forces that have the same magnitude bit opposite directions and are separated by a distance (d).
Moment of Couple:
The moment produced by a couple is called Moment of a Couple.
We determine the moment of Couple of a system by the algebraic sum of moments acted on the object, which is given by:
M = Ma + Mb
Couple moment is a free vector, so it only depends on the position vector between the forces.
There are two analysis of formulating couple moment:
1. Scalar Formulation:
The moment of Couple by using scalar Formulation is given by :
M = Fd
2. Vector Formulation:
The moment of Couple by using vector Formulation is given by:
M = r × FΣ
Equivalent Couples:
If two couples produce a moment with the same magnitude and direction, then these two couples are equivalent.
Resultant Couple Moment:
Since, couple moments are vectors, their resultant can be determined by vector addition.
M = Σ(r × F)
Or
Resultant Force = ΣF
Resultant Moment = ΣM at origin + ΣM
Or
Resultant Force along x = ΣFx
Resultant Force along y = ΣFy
Resultant Moment at O = ΣMo + ΣM
Reduction of a Simple Distributed Loading:
A uniformly distributed load is a load that is distributed or spread across the whole region of an element. In other words, the magnitude of the load remains uniform throughout the whole element.
Magnitude of Resultant Force:
The Magnitude of resultant force Fr is equivalent to the sum of all the forces in the system, which is given by:
Location of Resultant Force:
The location of force or the geometric center or centroid of the area under the distributed loading is given by:
And, the location of centroid of area under distributive loading for different shapes are:
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...
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...
Radiation Radiation effects are significant at high temperature. No material medium required. Every body above 0 kelvin emit electromagnetic waves (disturbance of photons). Radiation heat fluxes: Emissive Power (E) ⇔ rate of emitted radiations. It is a function of temperature. Irradiation (G) ⇔ rate of incident radiation on a body. Radiosity (J) ⇔ total radiation that leaves the surface. Net Radiative Flux ⇔ it is difference between radiation outgoing to radiation incoming. Solid Angle: Radiation Intensity: It is defined as, "rate of emitted radiation per unit area per spectral intensity (wavelength) per solid angle". Blackbody Radiations It is a hypothetical body with: No reflection and transmission. Radiation intensity is governed by Planck distribution 1. Wien's Displacement Law To find maximum emissive power, differentiate function with respect to wavelength and put it equals to zero. 2. Stefan - Boltzmann Law For finding total emi...
You can better get Engineering statics material from YouTube by the same name engineering statics
ReplyDelete