Analysis on Rupture Plate for different Cases

Aim and Objective

To Simulate the Rupture Plate and run for different cases and infer the results

Case Setup and Execution

Case 1

Default given file FAILURE_JOHNSON_0000 and FAILURE_JOHNSON_0001 was given and analysis was done

Material Properties

Image and Graph

Inference

• Johnson failure card is used Law 2 is applied
• `sigma = a+b epsilon^n_p;` considering Temperature and strain rate as constant
• Isotropic elasto- plastic behaviour is applied
• Von mises hardening takes place without damage
• `epsilon_f =[ D1+D2 exp(D3 sigma^@)]` Maximum Stress, EPS_p_max are defined so, failure elements are predefined
• If Ixfem =0: failure - elements are deleted

Case 2

Same model in Failures Changed ifail_sh =1; Dadv=1 ; Ixfem =1 and analysis was done

Image and Graph

Inference

• In this case Same model is run by changing
• I_{fail_sh = 1 ; If Ixfem =1: failure - element cracked.}
• _{Dadv =1 Then Dadv = 1 (max accumulation damage value D, used for crack initiation)}
• _{Ixfem =1 ;Realistic behaviour can be observed- Discipates Energy; Represents crack over an element}

Case 3

Same model Deleted Failure and Analysis was done

Image and Graph

Inference

• In this case same model is run for analysis but failure card is deleted
• Now element deformation takes place based on EPS_p_max and Maximum stress value
• As the failure card is deleted we can see elements are getting deleted.

Case 4

Deault file was taken, In materials Properties Eps_p_max value was made 0 and analysis was done

Image and Graph

Inference

• EPS_p_max it is material failure determining criteria; it also defines when/ at which particular integration point the elemet fails
• When EPS_p_max is equal to 0 we can see the elment is getting deleted un-uniformly unrealistic manner

Case 5

Default file was taken Material Property was changed to Law 1 M1_ElAST default values were given analysis was done

Image and Graph

Inference

M1_ELast

• It applies for linear elastic material based on hooke's law
• This material card is used to models of purely plastic materials
• As we can see in animation the impact is unrealistic
• It's like impact taking on a blanket rather than rupture plate
• The impact on model is non linear so, Law27 can be substituted instead of Law1
• The deformation is smooth and cracking at the end pointwise.

Case 6

Given LAW27_0000.rad file is imported and analysed with default conditions

Image and Graph

Inference

• Law 27 is Elastic Plastic Brittle
• As we can clearly see the element is getting deleted
• I_shell, I_smstr , I_sh3n, I_thick are default values due to which there is increase in hourglass energy
• Uneven distribution of elements during impact
• Nodal distribition issue is found
• Irregular pattern of impact is seen

Case 7

Given file FAILURE_JOHNSON_0000.rad is imported and new Curve is added with Stress VS Strain graph and analysed by applying Law 36 M36_PLAS_TAB

Image and Graph

Inference

• In this case Stress Strain curve is defined from experimented values
• Law36 is applied; Elastic Plastic - Tabulated
• Failure johnson card is defined
• The Elements are deleted during impact
• Ixfem is 0 in this case so, failure creteria based on `epsilon` which is dependent on D1 D2 D3 values
• Higher curve leads to higher strain which is faster failure

Graphs

• If we look into graphs Engergies are similar with slight variations except in case 6 and 5(Parabolic) there has been increase in hourglass energy due shell properties
• Case 5 has parabolic curve which shows elastic property
• Case 7 better results can be obtained by changing Stress Strain values

This data is taken from _0001.out file of every case when opened using Notepad

Results and Conclusion

• If we look into case 6 energy error is -7.1% it means more energy has been discipated
• In case 2 due to effect of I_failsh , Dadv, Ixfehm values had effect on element deformation
• Remaining cases except case5 the Simulation can be accepted for on field scenario; Case 5 Law 1 is applied based on linear deformation
• But here in rupture plate the deformation is non linear
• In case 1 the analysis is based on `epsilon_f`value and sig_max value as EPS_p_max value is 0
• In case 3 deletion of elements due to deletion of Failure card; deletion of elements is based on Ixfehm
• In case 4 Ixfehm = 0 with failure card; but elments were deleted based on `epsilon_f` value
• In case 5 is based on law 1 which is applicable for linear deformation; the simulation unrealsitic and impractical
• In case 6 LAW 27 is applied , In which beyond yield stresss the material damage is accounted before failure
• In case 7 LAW 36 is applied; higher the curve higher strain then faster failure; better results can obtained by altering Stress Strain values.