Theory of Metal - Strain and stress computation based onvisioplasticity
TASK:
The plane-strain deformation for a marked grid with 1 mm spacing is given below. Compute the strain rates, total equivalent strain and stresses at point P. It is estimated that the Cauchy stress in the perpendicular direction at the inlet is σ3 = 200 MPa. Flow curve of the material is defined as
σ = 500(0.003 + ε)0.18.
You will get a high percentage of bonus if you can program this computation in MATLAB. For this what you need is as follows: - Pixel to real scale factor (open the picture in MATLAB and specify two locations which has a given amount of millimetric distance) - click on the pixel locations necessary for the computation - corresponding real distances are computed using the scale factor You can also solve the exam question manually. Please note that this is plane-strain deformation. Don't forget to use the strain definitions accordingly.
In case you need a value for either quasi-time or quasi-velocity please take it unity "1". By this way you will get a normalized strain rate computation. But the total strains will remain the same.