Challenge

Assignment 4-RADIOSS Material Laws Challenge

SSarbesh Kumar25 Jun 2023

Report on Assignment 4-RADIOSS Material Laws Challenge

we follow the instruction as mention in all the cases then we proceed

1. The Total number of cycles, Energy error, mass error, and simulation time.

Number of Cases	Total number of cycles	Energy error(%)	Mass error(dM/M)	Simulation time(sec)
1	49380	0.8	0	49.77
2	49217	4.1	0	75.54
3	49408	0.8	0	49.34
4	48737	3.0	0	49.92
5	47969	1.3	0	45.67
6	53144	-1.8	0	50.74
7(1)	41113	-7.1	0	42.29
7(2)	49508	0.8	0	53.49

Note :- case 7 has two part, 7(1) one is without implimentation of recommended shell properties, 7(2) is with implimentation of recommended shell properties,

In above 7 cases there is no mass error , as we have applied different material card and recommended shell properties, In case 2 ERR is increases as compared to case -1,In case-3 ERR is remains same as compared to case -1,

2. Notice the animation of all 5 and describe the animations in brief based on whether the elements are being deleted or cracked

Number of Cases	Failure of Elements	Remarks and Comparisions
1) Law2_epsmax_failure		Here Elements are getting deteled after failure because here Ixfem value is 0
2) Law2_epsmax_crack.		Here Crack is propogated and element is not deleted here Ixfem value set as 1 , it means it will not delete the element after failure and that's why it will break after crack propogation
3) Law2_epsmax_nofail		Here we performing the simulation by removing the fail_Johnson failure card, the elemental failure, Hence element failure can't be observed, it will not detect criteria for failure of element without fail johnson card and in the only presence of EPS_p_max it might give unreal result for strains
4) Law2_epsmax_nofail		Here we performing the simulation by removing the fail_Johnson and failure plastic strain (EPS_p_max) , Here Eps_max is plastic strain at failure, failure happen when 1 integration point reach Eps_max. sometime it give unrealastic result at some instance hence we are using fail johnson card to get more control hence if we remove both the cards we can detect the failing element and their reasons
5) material card to Law 1		Since we had used Law_1 material card, it is linear elastic which follow hook's law , and we can see that the elements are neither deleted nor cracked because after impact it regain it origional shape
6) law 36 material card		Law_36 helps in modelling isotropic linear elasto-plastic using user defined function for work hardening portion of the stress-strain curve for different strain rates This Material law is available for both brick and shell element Law_36 have 4 damage and rupture parameter Eps_max is for deletion of any loading like tensile, compressive or shear Eps_t is for begining of tensile damage Eps_m is end for tensile damage Eps_f is for tensile failure strain value for element deletion So here we can observe that elements are getting deleted
7(1) law 27 material card without Recommended shell properties		Law_27 holds good results for orthotropic brittle material Since brittle is mention , the failure happen only in tensile loading and this law is only available for shell element So here we can observed elements are getting deleted due to sudden fracture as observed in brittle material due to tensile loading
7(2) law 27 material card with Recommended shell properties		Here the Materials are not deleted due to implimentation of recomended shell properties I shell-24 i.e QEPH , it is an improved under-integrated 4 noded element with 1 integration point on the surface, it stabilized the physical hourglass and in this case hourglass is reduce to zero Hourglass modes are non-physical modes of deformation that occur in underintegrated element and produce no stress I stmr-2 i.e large strain with full geometrical nonlinearities , it means it is suitable for the problem with large displacements and strains

3. Plot energies and notice any difference.

Number of Cases =>`	1) Law2_epsmax_failure	2) Law2_epsmax_crack.	3) Law2_epsmax_nofail Deletion of only fail johnson card	4) Law2_epsmax_nofail Deletion of both Eps_max and fail johnson card	5) material card to Law 1	6) law 36 material card	7(1) law 27 material card without Recommended shell properties	7(2) law 27 material card with Recommended shell properties	Remarks
Internal Energy									Here case-1,2,3,6,7(2) has almost same trend but in rest of the cases internal energy variation is changes due shell formulation and material property changes
Kinetic Energy									In case 1,2,3,5,6,7(2) K.E chages is almost same first it is vary slowly and after some time is it shoot up that means after impact whatever the total energy its maximum part is shared in K.E in case 7(1) K.E chages is most abruptly because absent recomended shell property
Contact Energy									Contact Energy is zero in all the cases
Hourglass Energy									Here alsoHourglass Energy is zero in all the cases except case-7(1) due to absent recomended shell property
Total Energy									Here Total Energy variation is same in case- 1,2,3,6,7(2) is following same trend n case-4,5 the slope of the curve increasing , it is not a good sign because total energy must be constand for a stablity, case-7(1) due to absent recomended shell property hence the T.E curve different from other

So in plotting graph of different energies for different cases we can make a conclusion that whatever the Total energy it is shared in internal energy and Kinetic energy (contact and hourglass energy is zero in most of the cases) i.e T.E=Internal.Energy+K.E

for stability condition T.E remains constant

Assignment 4-RADIOSS Material Laws Challenge

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