answersLogoWhite

0


Best Answer

Short answer:
strain engineering = change in L / original L
true strain = ln(1+strain engineering)

Engineering strain is the change in length divided by the original length, so that a 1 inch part strained 50% or .5 in/in would become 1.5 in or if strained -50% or -.5 in/in would become .5 inches. But these two strains are not the same amount of deformation since as a material is stretched further the change in length is distributed over a longer length for positive values and over a smaller length for larger values. Consider progressing from the now 1.5 in. (50%) strained part and continuing to 100% and the .5 in. (-50%) strained part and continuing to -100%. The next change in length is distributed over 1.5 in. and .5 inches respectively despite this the equation considers this change relative to the same original length of 1 inch. True strain is the change in length divided by the instantaneous length integrated from the original length to the instantaneous length. This resolves to the equation above.

Engineering Stress is more of an approximation. As stress levels increase, the actual cross sectional area of the object will change due to the force (think of a rubber band getting thinner as it gets stretched out).

Since stress is force divided by area the stress changes as a product of two variables. If you think of it that way, you are thinking of true stress.

Engineering stress holds the cross sectional area constant at its original value.

So if you look at a stress strain diagram, engineering stress levels off at the ultimate strength but true stress continues to climb because it is being divided by a smaller and smaller number as the object is stretched to the point of failure.

User Avatar

Wiki User

βˆ™ 15y ago
This answer is:
User Avatar
More answers
User Avatar

Wiki User

βˆ™ 15y ago

Strain is the deflection divided by the original length. It is unitless, and usually reported as a percentage. As an example, lets say you have a 1.000 long specimen. Under tensile load, it measures 1.020 in the same units (inches, centimeters, etc...). The deflection is .020 in those units. The strain is .020/1.020 = .0196, which is unitless. This would normally be reported as a %, so the strain = 1.96%.

This answer is:
User Avatar

User Avatar

Wiki User

βˆ™ 14y ago

true strain

This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: Which is more accurate-true strain or engineering strain and why?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Continue Learning about Mechanical Engineering

What is the relationship between engineering strain and percent elongation?

strain is percent elongation/100; for example a strain of 0.02 is 2% elongation. Often we refer to elongation at failure; for example if a material fails at 10% elongation its strain is 0.10


What is the difference between engineering strain and true strain?

Without getting into all the math, the engineering strain utilizes the initial length of the specimen in the calculation, the true strain utilizes the instantaneous length of the specimen.Getting into the math:strain engineering = change in L / original Ltrue strain = ln(1+strain engineering)Engineering strain is the change in length divided by the original length, so that a 1 inch part strained 50% or .5 in/in would become 1.5 in or if strained -50% or -.5 in/in would become .5 inches. But these two strains are not the same amount of deformation since as a material is stretched further the change in length is distributed over a longer length for positive values and over a smaller length for larger values. Consider progressing from the now 1.5 in. (50%) strained part and continuing to 100% and the .5 in. (-50%) strained part and continuing to -100%. The next change in length is distributed over 1.5 in. and .5 inches respectively despite this the equation considers this change relative to the same original length of 1 inch. True strain is the change in length divided by the instantaneous length integrated from the original length to the instantaneous length. This resolves to the equation above.


What is strain and equivalent strain?

There are 6 vectors used to describe the strain field of an element. An equivalent strain is just a single numerical value used to represent the strain field.


What is better automobile engineering or civil engineering?

I will suggest you to choose oil and gas field which has good market in upcoming years compare to other fields u can do mechanical or civil engineering both or an evergreen field. After your engineering get specialized in Piping Engineering or Process Plant civil Engineering . To have more confident in Piping or process plant Civil engineering field you can choose Seabird engineering institute


Strain of bacteria?

s-strain bacteria make

Related questions

What is plane strain condition?

the plane- strain conditions in civil engineering is that state in which the strain in one direction is zero as in long retaining walls, strip foundations, ...etc.


What is the relationship between engineering strain and percent elongation?

strain is percent elongation/100; for example a strain of 0.02 is 2% elongation. Often we refer to elongation at failure; for example if a material fails at 10% elongation its strain is 0.10


Define shear strain in civil engineering?

Strain shows how much longer a beam becomes after applying a force in a chosen direction.Strain = change of length of the the beam / original length of the beamIn case of Shear Strain force is applied only parallel to the surface of the beam (not normal to it).The same principal can be applied not only to beams, but to other civil engineering components as well.


Out of civil engineering and mechanical engineering which have more value?

civil engineering has more value civil engineering has more value


What is the difference between E and nu in engineering geology?

E is generally taken to be the elastic constant known as Young's modulus which describes the relationship between axial stress and axial strain where Hooke's law still applies (i.e. linear elasticity). Nu is Poisson's ratio which is the relationship between axial strain and radial or transverse strain. For more information, please see the related link.


Are they more physics in electronics engineering or mechanical engineering Which one goes deeper?

There is more Physics in Mechanical engineering as compared to Electronics engineering.


What is the difference between engineering strain and true strain?

Without getting into all the math, the engineering strain utilizes the initial length of the specimen in the calculation, the true strain utilizes the instantaneous length of the specimen.Getting into the math:strain engineering = change in L / original Ltrue strain = ln(1+strain engineering)Engineering strain is the change in length divided by the original length, so that a 1 inch part strained 50% or .5 in/in would become 1.5 in or if strained -50% or -.5 in/in would become .5 inches. But these two strains are not the same amount of deformation since as a material is stretched further the change in length is distributed over a longer length for positive values and over a smaller length for larger values. Consider progressing from the now 1.5 in. (50%) strained part and continuing to 100% and the .5 in. (-50%) strained part and continuing to -100%. The next change in length is distributed over 1.5 in. and .5 inches respectively despite this the equation considers this change relative to the same original length of 1 inch. True strain is the change in length divided by the instantaneous length integrated from the original length to the instantaneous length. This resolves to the equation above.


What are the applications of mathematics in engineering field?

Math allows you to calculate load, forces, stability, fragility, stress, strain, it goes on for ever.


What is true stress and stain?

I'm assuming you mean the difference between true stress and engineering stress: Engineering stress is only accounting for the area given at the time before deformation. True stress accounts for the change in area that occurs as the material is stressed. If you stay in the elastic region, there will be almost no difference between the two.


Difeerence in engineering and engineering technology?

Engineering leads to a degree in engineering or applied science, while engineering technology does not. Engineers get paid more, typically get to do less hands-on stuff, and get a cool ring. And chicks like them more.


Is cyclobutane more reactive than butane?

Yes, cyclobutane is more reactive than butane due to its ring strain caused by the angle strain in the cyclobutane ring. This strain makes cyclobutane more prone to ring-opening reactions compared to butane.


The main goal of genetic engineering is to create oddities of science.?

No - the main goal of genetic engineering - is to eliminate weaknesses in the subject organism. Example 1 - Creating a strain of wheat that is resistant to disease False A+ls - Awesomeness399 :P