What is Stress concentration: Definition and 24 Discussions
A stress concentration (also called a stress raiser or a stress riser) is a location in an object where the stress is significantly greater than the surrounding region. Stress concentrations occur when there are irregularities in the geometry or material of a structural component that cause an interruption to the flow of stress. This arises from such details as holes, grooves, notches and fillets. Stress concentrations may also occur from accidental damage such as nicks and scratches.
The degree of concentration of a discontinuity under typically tensile loads can be expressed as a non-dimensional stress concentration factor
K
t
{\displaystyle K_{t}}
, which is the ratio of the highest stress to the nominal far field stress. For a circular hole in an infinite plate,
K
t
=
3
{\displaystyle K_{t}=3}
. The stress concentration factor should not be confused with the stress intensity factor, which is used to define the effect of a crack on the stresses in the region around a crack tip.For ductile materials, large loads can cause localised plastic deformation or yielding that will typically occur first at a stress concentration allowing a redistribution of stress and enabling the component to continue to carry load. Brittle materials will typically fail at the stress concentration. However, repeated low level loading may cause a fatigue crack to initiate and slowly grow at a stress concentration leading to the failure of even ductile materials. Fatigue cracks always start at stress raisers, so removing such defects increases the fatigue strength.
Say I have a rod with a notch at the very centre and another ro with a notch at the very end. Both rods are identical in length radius materials etc. Who would be impacted by the notch more? And if then both were to support a load at the end of the rod (both in tension), what effects would the...
1. In my materials science's exam, I had the following question: What would be the maximum force F to cause failure in a block that has been drilled at two place?
See following drawing:
(Lame paint skills, I know..)
2. Homework Equations
1) D/W
2) σ = F/S
The Attempt at a Solution
1)First...
Homework Statement
[/B]
I can't seem to get the image links to work sorry! Also, I think the question is supposed to say 2.5mm radius notch, not 10mm
https://imgur.com/Klxw4gG
https://imgur.com/C9d81Rl
https://imgur.com/7H421ou
Homework Equations
[/B]
q = Ka - 1 / Kt - 1
M = Fd
(σa / σ'e)...
Hi,
I had been reading about the fatigue stress concentration factor (Kf) which is reduced compared to the geometric stress concentration factor (Kt). The reduction in turn dpends upon the material's sensitivity to notches...
Homework Statement
The stress distribution along the section of a bar is shown below. From this distribution, find the approximate axial force P in kip.
Homework Equations
δavg=P/A
A= (.6+.6)(.5)
δavg=30ksi[/B]The Attempt at a Solution
P=(30ksi)(.6in2)=18kip
It says this answer is wrong...
Homework Statement
A flat part with constant thickness b is loaded in tension as shown. The height changes from 50 to 87 mm with a radius r = 4.0 mm. Find how much lower a load can be transmitted through the bar if the height increases from 50 to 100 mm and the radius increases from 4.0 to 10...
Hi,
I want to understand how stress concentration factor or notch factor is considered in FEA method.
Lets assume a case of stepped shaft which has got the left end of the shaft fixed with rigid wall and the other end being pulled by an axial load.
In the case of conventional calculation...
Can someone link a website or attach a picture of a chart distinguishing the differences between the stress risers in a shear pin (round circular shaft) with a V-notch groove versus if it was a rounded groove. I have been looking but can only find charts, tables and graphs for round circular...
Hi everyone,
I wanted to know the stress concentration factor (Kt) for a cantilever beam with a fillet at the root with a point load applied at the end. Can I get the stress concentration factor if this beam is a 3D beam (thickness is comparable to length)?
I had a look at Peterson's SCF...
Hi there
Are anyone familiar with tables of stress concentration factors, or the like for short beams for different span/depth ratios.
My beam is technically not a beam, but I would still like to estimate maximum bending stresses related to normal stresses caused by bending moment (sigma =...
Hi everone,
I am trying to make a rough estimate of fatigue life of a hollow shaft under pure bending at a particular load level.The hollow shaft has a shoulder fillet. The minuimum outer diameter is 69mm and the maximum outer diameter is 72mm with a transition radius of 6mm.The thickness of the...
i want to design a machine which is capable of applying all three types of loads that is axial, bending and torsion. Using this application of static loads , I want to measure the stress concentration factor.
Hello
I have done a Soderberg shaft design calculation, taking into account the stress concentration for a keyway. However, I've just noticed that I might need to adapt this for a feather type keyseat, or 2 (parallel, 180deg apart) keyways in the same cross section.
I'm sure I read...
Hi i was wondering if anyone could help me by showing me how to re-arrange this equation:
a=2b*(c\d)½ i need to make c the formula. Any help would be greatly appreciated.
Chris
Ansys WB, getting non-realistic stress conce. (stiffener tip on pipe column face)??
Hi,
I am facing a problem in getting accurate stress in Ansys WB for stiffened base plate supporting pipe column (See attached pics)
The problem is that I'm getting very high stress concentration at the tip...
Hello, I have a rod of two different diameters and I'm trying to find the stress concentration at the chamfer between the two diameters. I understand how to find the stress concentration factor, K, if the joint was a fillet (using r/d and D/d to find K in the appropriate table). However I can't...
Homework Statement
Square panel , elliptical hole, uniform pressure p in x direction. calc stress at end of minor axis. pt A
L=40in p=10psi a=1in b=0.5 in t=0.2 in
Homework Equations
i know that stress at end will be max stress multiplied by stress conc. factor.
bt i don't know...
Hello, in a recent lecture on introductory engineering, our professor made reference to a stress concentration factor that pops up due to inconsistencies or changes in the shape of a material subject to a load.
The introduction he gave referenced a method of stopping cracks by drilling a hole...
Most texts have stress concentration factors for a stepped shaft in tension that has a radius where the smaller shaft meets the larger one such as this reference:
http://www.pirate4x4.com/tech/billavista/PR-BV60/Materials/7.jpg
I'm looking for a reference (perhaps "Peterson's Stress...
Can anyone help with how to find the analytical solution to problem involving finding the stress concentration around a circular hole in a flat plate.
The plate is has tensile load on both sides.
What are the cases for section 1 and 3??
this is a stress concentration factor of notched or fillet bars problem.
From the picture,how can we choose whether it is t=tension,z=compression or b=bending??
http://files.filefront.com//;5410211;;/
and...