Register to reply

ANSYS-Steel beyond yield point -Engineering strain or true strain for Plastic strain

Share this thread:
Dec2-12, 05:50 PM
P: 45
I am trying to do a problem on Material Non-linearity , to model steel for large deformation , beyond yield point ,
I have tensile testing data for the steel ( in form of Engineering stress vs Engineering strain).

for defining the model , I chose Multilinear Isotropic hardening
now there are 2 options
stress vs total strain & stress vs Plastic strain

Which option should I choose ( I was asked to choose Stress vs Plastic strain )
Also , what values should I use ? Engineering stress , Engineering Plastic strain (engineering strain - engineering stress/youngs modulus ) ;
or True stress and true strain values ( I know how to calculate them )

can any one clarify?

Also , to make it clear , I am trying to simulate a 4 point bending test , I know how to do contact analysis etc , I am only confused about the material modelling part
Phys.Org News Partner Science news on
'Smart material' chin strap harvests energy from chewing
King Richard III died painfully on battlefield
Capturing ancient Maya sites from both a rat's and a 'bat's eye view'
Dec26-12, 06:45 AM
P: 2
Sir, since you are concerned with the field of material science, may I ask a question in that regards??

I wanted to know why are there two yield points in a stress strain curve ?
Dec26-12, 07:16 AM
P: 5,462
The difference between engineering strain and true strain only becomes significant when phenomena such as tensile necking occur.

In normal engineering structures plastic analyis is conducted as a transition from linear-elastic to full plastic and the resulting stress block deduced, often as the formation of a plastic hinge. In this type of analysis the strain remains small and limited by elastic engineering considerations.

Dec26-12, 08:26 AM
P: 2
ANSYS-Steel beyond yield point -Engineering strain or true strain for Plastic strain

thnksss.....but i was asking about the upper and lower yield points....the case of true engineeriing stress-strain curve and normal stress-strain curve arises only after the ultimate failure stage...
can you tell something regarding the reason as to why there are two yield points, upper and lower??

Register to reply

Related Discussions
True Stress-Strain Curve on the Log Scale: Which portion is the plastic region? Mechanical Engineering 3
Getting stress-strain data using the 'strain hardening exponent'. Mechanical Engineering 0
Where to place strain gauges to measure shear strain on a continuous supported beam Mechanical Engineering 0
Strain, thermal strain and agle of twist Engineering, Comp Sci, & Technology Homework 0
What's the physical meaning of true shear strain and simple shear strain Atomic, Solid State, Comp. Physics 2