Week - 9 Material modeling from raw data

OBJECTIVE-

the objective of this project is to extract stress-strain data from a curve and find young's modulus and yield stress, convert into true stress, effective plastic strain. the extracted data must be loaded into material card and simulated by simple dog bone specimen

Procedure

1. extract data from curve( using digitalizer)

the data is extracted and saved as excel file

2. Data cleanup

the purpose of data clean up is to make sure there are no discrepancies and smooth curve is obtained because Ls-dyna need to smooth curve to understand material behaviour

In my case the curve is smoooth there is noo need to create another curve using trend line

3. Unit conversion

the given units are in KSI they must be coverted into GPA

1 Ksi= 0.00689 Gpa

youngs modulus is found and it is converted into KG-MM-MS, Youngs modulus is found and converted into KG-MM-MS

4.Conversion of ENG stress and Eng strain into TRUE STRESS and EFFECTIVE PLASTIC STRAIN

by Necessary formulas the the values are converted into true stress and true strain

5.Conversion of given data into curve

ls dyna understands elastic region by using youngs modulus, but the plastic region is given after yield point. the curve after yield point is given by DEFINE_CURVE the data obtained is loaded into it in note pad ++

6.Simulation- for the given file boundary conditions are given as follows

one side is fixed(SPC), displacement is given to other side for given model or geometry in x direction(BOUNDARY_PRESCRIBED_MOTION) and lcid is given for it

section shell is defined for given for this geometry

MATERIAL PROPERTIES are give in MAT_24 with obtained values

LCSS curve is given from values given after yield point

MAT and SECTION are given or referenced in PART keyword

database options and control termination is given

the .k file is saved and solved

RESULTS

.k file is solved

the results have been obtained

v-m countour

it is evident that max v-m stress or true stress obtained is 0.189 gpa in the red region in displayed contour at element 116

EPS Contour

it is evident that max eps at element 116 is 0.05.

eps and v-m graphs

validation of material data by comparing with curve obtained in excel

the curve looks same as input data.

Conclusion-

The raw data is obtained form given image and cure fitted,converted into material card Using mat 24 and the simulation has been done by using dog bone specimen

the validation has been done by comparing results obtained and input data.