# What is Yield strength: Definition and 35 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.

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1. ### Find Yield displacement and Yield strength of steel under cyclic load

TL;DR Summary: I have experimented metal bars under cyclic load, you can find the picture attached of the hysteresis loops of "Load vs displacement" of the experimental work... 13 steps (each step 3 cycles) Now I want to find the point where the steel started yielding and the yield strength so...
2. ### Determining the Yield strength and Ultimate tensile strength of HDPE

Help would very appreciated. Also I am new to this website so if something seems wrong please tell me :)
3. ### Work related problem: Yield strength as well as max load

Summary: Yield Strength value as well as maximum load capacity. Need equations and possibly a break down on how to solve the issue. So let's say I have a Wooden Street pole and I want to mount a steel bracket using metal bands to the street pole. The bracket will be mounted to the beam using 4...
4. ### How to calculate flexural yield strength?

I'm trying to learn some new engineering, so if something I ask doesn't make sense -- remember I'm new to this. I need to calculate how much force a part can take before breaking. Material: resin (Flexural Yield Strength: 6752 psi) - (Tensile Strength: 3390 psi) - (Density [lbs/gal]: 9.64) -...
5. ### Elasticity (Yield Strength) of Carbon Nanotubes

I'm trying to find the Yield strength, that is how much force can be applied to carbon nanotubes so that they stretch to the limit before plastic deformation. And also how much they stretch at this limit. Do they stretch at all? Or are they always the same length until the Ultimate Tensile...
6. ### Tensile yield strength of fiber reinforced plastic

Hello! I am in a student-run engineering team that heavily utilizes fiber reinforced plastics, and I am just trying to get a better understanding of FRPs. I am wondering how exactly the fiber reinforces the plastic. Let's say the yield strength of the fiber in the 0 degree tensile direction is...
7. ### Understanding Yield Strength & Stress Strain Curve

Hi all I was hoping someone could shed some light on the following:- I am trying to understand what Yield strength is and understand the exact limit of where elastic and plastic deformation occurs on a stress strain curve. Correct me if I am wrong but I define:- Yield strength as the amount...
8. ### Steel hardness vs yield or ultimate strength?

I have found sources that state hardness can't be correlated to yield strength, but only to ultimate strength. Other sources state the opposite. Yet other sources claim you can do both with different equations. Can someone direct me to a source that addresses my question, or addresses the...
9. ### 40 foot shipping containers, yield strength / buckling

Hi, I am currently needing to place (and weld to the ground) a shipping container on a low bridge that is perpendicular to the shore. I was wondering if anyone knows how much force the sides of the container can withstand before buckling and/or bending. In essence, we have to account for very...
10. ### Desai Yield Surface, Parameters

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...
11. ### Difference between 'plastic yielding' & plastic strength?

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...
12. ### Torsion constant of a bent spring

How do I find torsion constant (Kt) of a spring which is bent, as shown in the image below
13. ### Finding the maximum load of a bar from the yield strength

I have a flat steel bar (30 mm width, 5 mm thick, 1100 mm long). The bar has a load applied in the centre of 100N. the bar is fixed at both ends with a single concentrated load P applied mid-span the maximum yield stress is 250 MPa (250x10^6 Pa) How do I calculate the maximum load the bar can...
14. ### The yield strength at temperature SA-789/SA-789 М

Hi! Could you help me to find the yield strength at temperature SA-789/SA-789 М.
15. ### Unraveling the Stress-Strain Curve: Find Young's Modulus & Yield Strength

Homework Statement The figure shows the stress-strain curve for a material. The scale of the stress axis is set by s = 280, in units of 10^6 N/m2. What are (a) the Young's modulus and (b) the approximate yield strength for this material? Homework Equations E=stress/strain The Attempt at a...
16. ### Maximum stress as percentage of Yield Strength

Homework Statement Hi guys, I have a question here, which asks me to express the maximum stress from my simply supported beam, which I worked out to be 1.165MPa, to be expressed as a percentage of the Yield strength 95MN/m^2. I also have a follow on from that which asked me how much the...
17. ### 0.2% Offset vs. 0.5% Extension Under Load Yield Strength

Hello everyone, I have designed a part that should be able to withstand a shear stress of 43 MPa ( give or take). The part will be made of Nickel Aluminum Bronze (CuAl10Ni5Fe4). When I check yield strength values for this material (I'll multiply it by 0.6 to estimate its shear strength), they...
18. ### Calculating Yield Strength for Dowell Pins

So how do I figure out if say a part is being made with a .250 round dowell pin at 100,000 yield strength and I want to use a material at 60,000 yield strength how much bigger would I have to make the dowell pin to achieve the same yield strength?
19. ### Brittle Materials: Bending Yield Strength

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...
20. ### Finding yield strength with modulus of elasticity

Homework Statement Grade 1020 Steel has a yield strength of 42ksi and E modulus of 30 mpsi. Another grade of steel has yield strength 132 ksi. What is its E modulus? Homework Equations E=FL/EA This is the equation i should be using to find e modulus I thing The Attempt at a Solution I don't...
21. ### Do you just multiply the Yield strength by the thickness?

The term yield strength is always bugging me deciphering the actual use in some cases. If I had a plate 3m x 2m 30mm material of Yield Strength 355N/mm², does this mean the maximum allowable force at one point on the plate is 10,650N (355 x 30mm), not taking into account safety factors...
22. ### Calculation Based on Yield strength and Ultimate strength

Hello Gurus, I am new to mechanical design calculations. Since I have came across one interesting fact there are two methods using for finding the shear capacity of the components. Yield Strength and Ultimate strength. Shear yeild strength=1/√3* Yield strength Ultimate shear strength=...
23. ### Mohrs Circle, Von Mises and Minimum Yield Strength Help

Hi Wasn't sure where to post this, hope it's ok in here! I've gotten myself very confused as to how to find the minimum yield strength for an element. I have used Mohrs circle to find sigma1 and sigma2, then plugged that into the von mises equation to find sigma-von = 636.8MPa. The...
24. ### Strengthening, crystalline alloys, and yield strength questions?

Hi, these are questions from my exam from the mechanical behavior of materials. I seriously screwed the exam up. Can you guys help me out? a) Provide two reasons why C is more effective than Ni in strenghtening Fe. b) Explain why single crystalline alloys with fine grains are more...
25. ### Using Stress/Strain Curve to Find Yield Strength and Modulus of Elasticity

Hey guys, I recently did a compression lab with different materials (wood and pvc pipe) and I have to plot the stress/strain curves given the data collected, as well as find yield strength (0.2% offset), ultimate compressive strength, and modulus of elasticity. I've already calculated...
26. ### Effect of Strain Hardening on Yield Strength

Homework Statement The strain hardening behavior of an annealed, low‐carbon steel is σ = 100,000ε0.2 If a bar of this material is initially cold worked 20%, followed by additional cold work of 30%, determine the probable yield strength of the final bar. Homework Equations σ=κεη...
27. ### Fan failure and yield strength

What will fail if the aluminium impeller rotating at 7500 rpm and powered by 355 kw motor strikes against the stationary 10 mm thick ms plate welded at both the ends having length of 350 and width 200 mm and impeller blade is 12 mm thick. I am confused in first glance we think that blade will...
28. ### Specific Yield Strength Question for A572 material

My industry (tubular steel poles) standardly uses A572, Gr65 and A871, Gr65 for shaft design with the designs taken to the minimum ASTM defined Yield and using loading factors in the design. The A572 specification has for years listed all grades as "Yield Point". The A871 specificaion (which...
29. ### Calculating Yield Strength using a Load vs. Displacement Curve

Hi, This question came up on my midterm and I had no idea how to answer it without redrawing the entire curve as a stress vs. strain curve (which obviously took too long to do). Anyway, I'm just requesting a general procedure, not a numerical answer. If you had a Load (y-axis) vs...
30. ### Finding Yield Strength, E, and TS

Heres my given problem: Gauge Length = 2 in. Area = 0.5 in^2 The specimen yields under a load of 32,000 lb The corresponding gauge length is 2.0083 (the 0.2 yield point) Max load = 60,000 lb @ gage length = 2.60 in I need to determine the yield strength, modulus of elasticity, and...
31. ### Need Help with Yield Strength for FEA

Hi, folks, I'm an aspiring Mechanical Engineer, & as such am very new to the subject of stress, strain, etc. I'm designing an assembly using a hi-performance polymer that has the following characteristics: Tensile Strength, 73°F 10.1 kpsi (10,100 psi) Tensile Modulus (E) 340 kpsi...
32. ### Difference between tensile and yield strength of a metal

Homework Statement differance between tensile and yield strength. please help. Homework Equations The Attempt at a Solution
33. ### Yield strength variation with temperature

anyone can help me out by providing the mathematical relationship between yield strength and temperature
34. ### Find the yield strength for an elastomer

Hey, Just wondering, how would you find the yield strength for an elastomer just from the engineering stress-strain curve. My professor said its complix and different books have different ways of finding it. Any ideas?
35. ### Yield Strength of Metal Plate: Rolling, Heating, and Cooling

Can someone help me explain how a plate of metal's yield strength changes as it is 1) Rolled (flattened) then 2) Heated for some hours and cooled, and then finally 3) Cooled and rolled additionally. Does the yield strength increase at first, then drop, and then increase again? That's what I...