The difference between true stress & engineering stress is summarised as follows:
Engineering stress assumes that the area a force is acting upon remains constant, true stress takes into account the variation in the cross sectional area as a result of the stress induced deformation (strain) of a material.
For example a steel bar in tension once its yield point or stress is reached will start to "neck". Necking is the localized concentration of strain in a small region of the material, causing a reduction in cross sectional area at this point.
To calculate the engineering stress in the above case, the applied load is divided by the original cross sectional area, however the true stress would be equal to the load divided by the new deformed cross sectional area. Therefore true stress is likely to be significantly higher than engineering stress. Note that while the material is deforming elastically before the yield point is reached there will be some difference between true and engineering stress (as the material is changing shape) but it will be much smaller than the difference after the yield point is reached.
A rock core in a uni-axial compression test will typically expand radially under loading. Therefore in this case, the engineering stress (based on the original diameter) will be larger than the true stress within the material.
True stress accounts for the change in area as the material is stressed:
Assuming homogenous plastic deformation at a constant volume, sigma_true=sigma_engineering*(1+strain)
However, as far as I know, that assumption is no longer correct once necking occurs, as the stresses within that region become unknown equations based on the deformation. I suppose with the right measuring equipment one could possibly find it, but I'm assuming that you'd be at a far more advanced level than my expertise could provide if that were true.
When you apply tensile pull on a specimen ex: rod, its length increases at the same time its cross sectional area decreases.when find stress by taking original area of cross section than it is known as engg stress. If you take reduced area than it becomes true stress.
As the material begins to fail, it stretches and yields and the cross sectional area is reduced. Thus, the true stress (load over area) is higher since area is smaller than the original area, on which engineering stress is based.
To illustrate this you can take a stick of soft Chewing Gum and stretch it; you will see the area reduce significantly before failure
because as failure approaches the cross sectional area necks down (reduces) then true stress is load divided by the reduced area. Engineering stress uses the initial area, and is the usual way to report stress
see following question:
What_the_difference_between_true_strain_and_engineering_strain
secret
Fracture stress is only less than ultimate tensile strength in an engineering stress-strain diagram. This is because the material will experience a maximum stress before it undergoes necking. After necking, stress will decrease again until the material snaps.
True
True!
T351 is stress relieved. Usually material certified to be T351 would also meet the requirements of- and could be dual cert'ed as T4. This is not true the other way around (material cert'ed as T4 may not dual cert as T4).
When engineering and administrative controls are not feasible or effective in reducing job related hazards the use of PPE is required.
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.
We almost always use engineering stress as that is the number reported in strength tests.
nominal stress is the engineering stress, which is the force divided by the original Area. true stress is the force divided by the area of the deformed specimen as it deforms. Since the area of the deformed specimen is usually smaller than the original area true stress is higher than the nominal stress... Ali D
see the following questionWhat_the_difference_between_true_strain_and_engineering_strain
One difference between Herkimwe diamonds and true diamonds is that the Herkimwe diamonds are softer than true diamonds.
A story can be true or not where as a tale is not true.
true
True means that it is correct. False means it is not true.
The Banker's Gain (BG) is the difference between a banker's discount and a true discount. It is a deduction with simple interest.
Dear friends,I hereby is trying to solve your problem.Diff b/w CS and IT in engineering:The Computer Science engineering is something which contains the specialization in particular computer field and the IT engineering is which contains all the technologies.Ya it is true that now a days in most of the technologies computer science is essential but if we sharply notice at the difference then-"A computer science engineer develops the logic but an IT engineer implements it into different equipments and that is the difference which CS and IT engineering have respectively."- Tomar
Knowledge is true, and belief is something that is claimed to be true.
True means correct, factual. False is the opposite - it means not true or not correct.