What is Yield stress: Definition and 25 Discussions
In materials science and engineering, the yield point is the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation.
The yield strength or yield stress is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing permanent deformation. In some materials, such as aluminium, there is a gradual onset of non-linear behavior, making the precise yield point difficult to determine. In such a case, the offset yield point (or proof stress) is taken as the stress at which 0.2% plastic deformation occurs. Yielding is a gradual failure mode which is normally not catastrophic, unlike ultimate failure.
In solid mechanics, the yield point can be specified in terms of the three-dimensional principal stresses (
σ
1
,
σ
2
,
σ
3
{\displaystyle \sigma _{1},\sigma _{2},\sigma _{3}}
) with a yield surface or a yield criterion. A variety of yield criteria have been developed for different materials.
Hi guys. Recently I've been assigned to know / calculate the capacity of the racks in our section. Our racks has layered steel pipes that are carrying the loads. After actual testing it can carry a load around 25 tons after yielding or having a bend. So my next step was to calculate for its...
I've been digging through literature the last few days, and I'm starting to wonder if increasing strain rate EVER decreases yield stress? I found anomalies which increase it with increasing temperature. But I cant' find the reverse, so I was wondering if it was possible?
Hi Forum,
I´m happy I found this forum...
I hope someone can answer my (simple) question:
According to this thread https://www.physicsforums.com/threads/calculating-0-2-proof-stress-of-aluminium.206648/ on page 2 the stress/strain diagram is not the same as force/elongation.
Due to the constant...
Hey guys,
Desai Yield Surface:
I have a hard time understanding the parameters of the model for soils. If I have three principle stresses, σ1, σ2, σ3. And R is defined as the Tri-axial strength in tension, how would I define R.
Lastly can I just say that
I1 = σ1+σ2+σ3
J2= 1/6 * ((σ1-σ2)2...
Homework Statement
In Euler's theory , it's stated that the critical stress of beam is always larger than the yield stress of beam ...I don't really undertstand the differnce between them . Critical stress is defined as the stress that the mximum stress applied before the beam starts to...
I am going through a literature where the terms like ( 'plastic yielding' , 'plastic yield strength', plastic strength' and 'plastic stress') are regularly used and I am confused. Are they different and if yes then how each term differs from the other? I also want to know relation of plastic...
Homework Statement
For a larger project we had to redesign a truss to prevent certain members going beyond yield stress.
I've found that due to the nature of the reaction forces and the supports used, the only way to do this is to introduce an X-brace in the bay nearest the supports (as well...
Some metal give two yield point in stress strain diagram. One is called Upper yield point and Lower yield point. Why lower yield point is considered as more reliable. I can think of Upper yield point is much more dependent upon experimental apparatus settings. So why lower yield point is much...
I need to know why the Engineering stress increases after reaching the yield stress point, and continues to increase until reaching the UTS. Am I correct when I remember that there is strain hardening that occurs along the region from Yield stress to the Ultimate tensile stress? Engineering...
It seems to me that the ultimate strength of a brittle material can be easily determined by a bending test, but what about the yield? In the brittle regime, I can see how you couldn't, since the sample would fail before it would flow significantly. However, brittle materials can be made to flow...
If I have the differential yield stress σd=(σ1-σ3) for a material, what can I derive from that for use with the von mises criterion? Do I have k=0.5×(σ1-σ3) or σy in axial tension, where σ3 = 0? Essentially is my axial yield stress = σd or √3 × σd /2? (in plane stress)
I have a cylindrical steel sample tested in tension. It's cross-sectional area is 500 mm2. I am also told that:
Force at yield = 205 kN
Maximum force = 258 kN
Force at fracture = 200 kN
I am asked to calculate the yield stress, ultimate tensile stress and fracture stress if the reduction of...
Hi, from what I know, the crushing force for sugar cane is somewhat similar to pine wood which is about 40 MPA. But since there's water content in it, I need to readjust the yield stress for to crush the sugarcane.
I've tried googling it but couldn't find much useful information. Anyone knows...
Greetings all,
I have been trying to find a method of calculating the yield stress for a material when only given;
-The loading type (Two bars soldered together in tension)
-The dimensions of the shaft and solder (ie thickness of solder, length, cross sectional area)
-The Ultimate...
Are those the same? if not, how do I calculate the initial yield stress from the tensile strength? all the materials properties I see on the web only specify tensile strength, and I need the initial yield stress as an input on non-linear FEA analysis. Is it possible to extract the initial yield...
1. Homework Statement I have a bar, 500mm long (0.05m) 10mm wide (0.01m) and 3mm deep (0.003 m)The bat has a load applied in the centre of 30nI know the maximum yield stress is 150 mpa 150x10^6How do I calculate the maximum load the bar can take?2. Homework Equations I used stress = m y / I3...
Homework Statement
I have a bar, 500mm long (0.05m) 10mm wide (0.01m) and 3mm deep (0.003 m)
The bat has a load applied in the centre of 30n
I know the maximum yield stress is 150 mpa 150x10^6
How do I calculate the maximum load the bar can take?
Homework Equations
I used...
Hello,
I'm new here and so if I've put this in the wrong section or anything, please let me know and I'll fix/change whatever needs to be done.
I just wanted to see if someone could help me understand something.
When choosing a torque value, is it just ~90% of the yield stress of the...
Right this is the question,
Determine the yield stress for a metal with an average grain diameter of 0.045mm, if the yield stress for a metal changed from 650Nmm^-2 to 720Nmm^-2 when the average grain diameter decreases from 0.054mm to 0.037mm.
I cannot figure this out, I've been trying...
Homework Statement
I am given the trends for yield stress and fracture toughness as functions of temperature for steel. I need to explain the trends
Homework Equations
none
The Attempt at a Solution
I am guessing the yield stress is the stress that the material can withstand...
Is Yield Stress for a fluid a real property?
Or is it a time dependent illusion we are measuring?
For example - some glass materials are referred to as super-cooled fluids and yet behave and appear like solids. In reality though these super cooled fluids flow - very slowly.
Some old...
Is it possible to find the yield stress of a material with only modulus of elasticity and Poisson's ratio?
I was given a problem that:
What is the min. aluminum needed to support a block (10 Newton) to 1 meter high? E=70GPa and v=0.3 are the only given aluminum properties.
I would know...