Introduction to Strength of Material (SOM)-Mechanics of Deformable body
Strength of Material :-
It is study of internal resisting force developed due to elastic deformation of a body under the action of load.
Assumption made in Strength of Material Equation:-
Material is assumed to be homogeneous and isotropic.
Component is assumed to be prismatic.
Load is assumed as static load
Effect of self weight is neglected.
Static Load:-
When magnitude and direction is constant with respect to time.
Prismatic:-
All dimension are constant or same throughout the structure.
Homogeneous:-
Material is said it be isotropic, when it exhibit same elastic property at a point in a given direction.
Isotropic:-
Material is said it be isotropic, when it exhibit same elastic properties in any direction at a given point.
Wednesday, 10 October 2018
Hi Every one welcome to my engineering blog.I am glad to introduce that we are starting new video series fully dedicated to FEA and CAE field . Manly we will cover some journal topics based on Hypermesh and Ansys Workbench software with theoretical concept.Hopeing that you will support the chnanel.
Pressure vessel is defined as closed
cylindrical or spherical container which is designed to hold or to store fluids at
pressure substantially different from ambient pressure.
Classification of Pressure Vessel.
1.based on d/t ratio:-
1.Pressure vessel whose d/t ratio is greater than 20 units, such type of vessel is categorized to Thin walled pressure vessel (d/t
≥ 20).
Ex. Boiler shell, LPG cylinder
pressure cooker, storage tank
2. Pressure vessel whose d/t ratio is less than 20 units, such type is called as Thick walled pressure
vessel (d/t≤20).
Ex. Hydraulic cylinder, gun Barrel,
Storage tank
under high pressure
2. Based on Shape
of shell
1. Cylindrical
pressure vessel
2.
Spherical pressure
vessel DO comment !!!!!! 1.Why Spherical vessel better then cylindrical pressure vessel? 2.Which vessel we should used for safety purpose? 3.Which vessel we should used, keeping manufacturing cost in mind?
Bursting of pressure vessel occurs circumferential.
Condition-1
At particular
pressure, when longitudinal stress in thin walled pressure vessel is greater than ultimate strength, circumferential bursting occurs in pressure vessel.
σL> sut
FF
=
FR
FF= (π D2 P)/4-------------------------------i
FR=σLxπ𝐷x𝑡--------------------------ii
(πD2P)/4 =σLxπ𝐷x𝑡
σL=σ2= σlongitudinal= pd/4t = σ1/2
Bursting of pressure vessel occurs longitudinally.
Condition-2
At particular pressure, when Hoops stress in thin walled pressure vessel is greater than ultimate strength, bursting occurs longitudinally in pressure vessel.
σh> sut
FF = 2xFR
FF= PxLxD-------------------------------i
FR=2xσhxLxt--------------------------ii
PxLxD= 2xσhxLxt
σh = σ1 = σhoop= pd/2t
Thin pressure vessel can be considered bi
axial state of stress
(due
to longitudinal
stress).
σ1 = σhoop = pd/2t
σ2 = σlongitudinal = pd/4t = σ1/2
In plane τmax
=(σ1-σ2)/2 = pd/8t
Absolute τmax
=σ1/2 = pd/4t
Strain
stress
Major principal strain
ε1=εhoop=δD/D----------i
ε1= 1/E [σ1-μσ2]-----ii
σ2 = pd/4t = σ1/2
Equating i & ii
εh=δD/D=σ1/2E x[2-μ]
εh =pd/4tEx[2-μ]
Minor principal
strain
ε2=εlongitudinal=δL/L----------i
ε2= 1/E [σ2-μσ1]-------------ii
σ2 = pd/4t = σ1/2
Equating i & ii
εL=δL/L=σ1/2E x[1-2μ]
εL= pd/4tEx[1-2μ]
Volumetric strain
δV/V=pd/4tEx[5-4μ]
Thickness
of the shell
Safe condition of design (σ max)ind ≤(σt )per
σ hoop ≤(σt )per
σ hoop cylindrical=pd/2t≤ (σt )per
σ hoop spherical=pd/4t≤ (σt )per
Thin
C.P.V
According to failure theory (MPST,MSST)
PD/2t= ≤(σt )per
t≥PD/2(σt)per+corrosion
Added
Thin
S.P.V
According to failure theory
(MPST,MSST,MDET)
PD/4t= ≤(σt )per
t ≥PD/4(σt)per+corrosion Added
Refer Static Structure Analysis for thin Pressure Vessel in Ansys for better understanding .
Structural steel design is an area of knowledge of structural
engineering where we used to design steel structures. The structures can range
from schools to homes to bridges. Structures such as buildings, bridges,
aircraft and ships are all examples which comes under steel structure.
The
effects cause on structure due to
application of load is determine through structural analysis Strength of materials
is the branch of engineering which deals with the study of structural design. Engineering
software such as STADD Pro, TEKLA , SACS, ANSYS
etc. are used to analyze their strength.
Basically Steel structure is steel
construction material with a unique
profile and a specific shape or
cross section with certain standards of chemical composition and mechanical
properties.
The American Institute of Steel
Construction (AI SC), Inc. publishes the Steel Construction Manual (Steel
construction manual, or SCM), which is currently in its 14th edition.
Structural engineers use this manual in analyzing, and designing various steel
structures.
The mentioned link will give you
the complete description of AISC 's structural steel shapes in the US and will provide you the reference to
determine the availability and engineering design data of specific structural
steel shapes.
(Click Here) Link:- AISC Structural Shapes
Click above link to find ASIC Structural Shape Properties
