## Comparison of Different Material Cards Laws for the Aluminum And Its Behaviour

1.Objective :

To compare the simulation of different cases by assigning different laws and also observing the corresponding behaviour of the material for the given model.

2.Explanation:

• Regarding files such as 0000.rad and 0001.rad files are required to run the simulation.
• Import the given 0000.rad file to the Hypermesh
• Now different law for materials is set such as law1, law2, law36, law27.
• The brief explanation of every law will be explained and the behaviour of the materials is also observed.

2.1.1 CASE 1:

• The simulation is carried out of the model where the aluminium ball is creating a huge impact on the aluminium plate.
• Here, both the material assigned is aluminium.
• The material is assigned as Law 2 which is nothing but the PLAS_JOHNS.
• No properties have been changed and run as such as the given model.
• Now run the simulation and the following outcome have been observed.

CASE 1 SIMULATION

CASE 1 GRAPH

2.1.2 CASE 2 :

• Now copy the 0000.rad and 0001.rad file of case 1 and put in the new folder for better understanding.
• Rename the file as Law2_eps_max_crack_0000.rad and Law2_eps_max_crack_0001.rad which is nothing but the starter and engine file.
• Now import the file to the Hypermesh and assign the material as FAIL_JOHNS law by giving the properties as Ifail_sh=1, Dadv=1, Ixfem=1.
• Then after running the simulation, the following observation has been made.

CASE 2 SIMULATION

CASE 2   GRAPH

2.2 COMPARISON OF CASE1 AND CASE 2

2.2.1 CASE 1

• In case 1 EPS_Max values are set as 0.151 which is 15%.
• Thus at 15% of the plastic strain, the material undergoes the rupture which is a failure.
• The material undergoes rupture due to the value assigned above. The EPS_Max value is as close as 1, the material undergoes rupture late according to the plastic strain deformation.
• We can observe in the above simulation that the rupture is so soon.
• The graph is plotted, The internal energy keeps ascending due to the impact.
• The material keeps on observing the internal energy and at some point, the internal energy curves stop due to the rupture of the material.
• The kinetic energy remained constant till the time of 3.8 milliseconds. The slight changes are due to the material element undergoes deflection which is the starting point for rupture.
• The total energy followed the traces of internal energy but at the time of 3.9, there is variation due to the effect of the kinetic energy.

2.2.2 CASE 2

• In this case, FAIL_JOHNS law is imposed on the material property
• By assigning the values of properties to the material, the following observation has been made.
• The cracking of each element can be seen visibly and also how much the particular element undergoes stress. The image in case 2 shows it clearly.
• The graph shows the result that cracks have been carried out for each element and the deflection occurs at the time of 4.6 milliseconds, which meant that due to the impact the crack is developed till the time of 4.6 milliseconds and ultimately ruptures.

2.2.3  RESULT :

• Thus the rupture in the case1 is so soon compared to the case2.
• In case 1 only the max plastic strain is set, but in case 2 due to the FAIL/JOHNS the material undergoes crack followed by the rupture.
• Thus the case 1 is better compared to case 2 in terms of internal stress and energy errors.

2.3  CASE 3 :

• The simulated rad files of case2 are taken as the input for the case 3
• Now after importing it to the Hypermesh, the FAILS/JOHNS card is deleted and the simulation is carried out to find the better results.

CASE 3

2.4 CASE 4 :

• The simulated rad file of case 3 is taken as the input for the case4
• Right after importing, the following material properties such as Eps_max is set as 0.
• And the simulation is carried out.

CASE 4 SIMULATION

CASE 4 GRAPH

2.5 COMPARISON OF CASE 3 and CASE 4:

2.5.1 CASE 3 :

• In case 3, The FAILS/JOHNS card is deleted and the simulation is ran.
• Again it is same as case 1, where the rupture takes place but not in the crack wise due to the removal of PLAS/JOHNS card.
• The rupture still takes places due to the eps_max value is still assigned the same as the 15%.
• The rupture took place at the time of 3.9 milliseconds which is as same as the case 1 as shown in the graph but the stress induced in the surfaces changes because of the plasticity region of the material.

2.5.2 CASE 4 :

• Since the removal of the FAIL/JOHNS and as well as the eps_max value, There is no rupture of the material as shown in the simulation image.
• It is because that the max plastic deformation value(eps_max) is not set.
• The graph shows the accurate results that internal energy keeps on ascending smoothly due to the energy absorption of the material and there is no kinetic energy because there is no deflection or rupture in the material.
• The total energy follows the same curve path of internal energy.

2.5.3 RESULT:

• Even the though the fail/johns are set and removed, it shows that the rupture takes place at the same time but stress induced in the surface of the case 1 is higher compared to the case 3. This is due to the material cannot able to withstand high stress because of more plasticity.
• In case 4, since there is no eps_max value, the rupture of the material in the plastic strain region is not assigned. The max stress-induced as 424 N/mm^2. The material acts more like a tensile material.
• The case 3 is better compared to the case 4 in terms of internal stress and energy errors.

2.6 CASE 5 :

• The simulated rad file of case4 is the input file for case 5.
• The model is imported in the Hypermesh and the material card is changed from PLAS/JOHNS to /ELAST.
• And the same density, youngs modulus as well as nu values are assigned.
• Then the simulation is carried out.

CASE 5 SIMULATION

CASE 5 GRAPH

• Thus the material acts tensile and absorbs more energy compared to the plastic region which prevents it from the deformation or rupture.
• The induced stress exceeds up to 1098 N/mm^2.
• The internal energy ascending smoothly and there is no variation because of there is no rupture or deflection of a material or element.
• The kinetic energy remains almost constant.
• The total energy follows the trace of the internal energy because the kinetic energy factor does not affect the curve much.

2.7 CASE 6 (Law 36) :

• The new downloaded Johnson cook file is taken as the input for the case 6.
• Import the rad file to the Hypermesh.
• Now before running the simulation, the material cards is set as PLAS/TAB.
• Also the values such as rho = 0.0027, E = 71000, eps_max = 0.9, eps_t = 0.4,            eps_m = 0.5
• New test curve is created for the values for x co-ordinates and y co-ordinates according to the stress strain value of the engineering lab.
• This implementation of the new curve is obvious to get the exact result.
• This is why because, the material has to follow only the plasticity curve to get accurate plastic strain. but in case PLAS/JOHNS the curve at start follows the tensile region and move on to the plasticity region in which it neglects the true stress and true strain value.
• Thus PLAS/TAB gives accurate results compared to PLAS/JOHNS but both are more or less same.

CASE 6 SIMULATION

CASE 6  GRAPH

• Thus the rupture takes place as same as the case1(law 2)
• In this case, more stress is induced in the material compared to the PLAS/JOHNS.
• Thus the material absorbs more energy compared to the PLAS/JOHNS and the rupture took place at the time of 4.1 milliseconds which is a bit late compared to the PLAS/JOHNS.
• The internal energy is ascending constantly but after the time of 4.1 milliseconds, the material undergoes deformation or rupture.
• Kinetic energy is constant but at the time of 4.1 seconds, the material started to deform.
• The total energy follows the same curve path of internal energy till the time of deformation due to the factor of kinetic energy.

2.8 CASE 7(law 27) :

• Import the file to the Hypermesh.
• Now assign the card as PLAS/BRIT(law 27) for the material.
• This law combines an isotropic Elasto-Plastic Johnson-cook material model with an orthographic brittle failure.
• This law is most applicable to the brittle material such as safety glass, windshield, etc.,
• Ifail_sh = 1, Dadv = 1, ixfem = 1
• d_max accelerate the failure of the model.
• The stress-induced gives accurate results.

CASE 7 SIMULATION

CASE 7 GRAPH

• Internal energy ascending until the deformation occurs
• Kinetic energy was constant and shows spikes at the end stating the deformation or deflection of the material.
• The total energy curve follows the internal energy and gets deviated at the end due to the kinetic energy.

3.Conclusion:

• CASE 5 -- Law 1(ELAST) produces internal stress of 10980 N/mm^2 which is maximum and the energy errors exceeding between -0.3 to 4.2% which is not recommended.
• CASE 1 -- Law 2(PLAS/JOHNS) produces internal stress of 287 N/mm^2 and the energy errors are exceeding between -0.2 to 0.7% which is appreciable.
• CASE 2 -- LAW2(FAIL/PLAS) produces internal stress of 294.7 N/mm^2 and the energy errors are in between 0.1 to 4.3%, so this process is not recommended.
• CASE 3 -- Law 2(PLAS/JOHNS) produces internal stress of 270 N/mm^2 and the energy errors are in between 0.3% to 0.8%, so the process is taken for the consideration.
• CASE 4 -- Law 2(PLAS/JOHNS) with the eps_max value of 0, produces internal stress of 424.7 N/mm^2 and the energy errors are in between of -0.03 to 3.0%, so this law is not recommended.
• CASE 6 -- Law 36(PLAS_TAB) produces internal stress of 270.05 N/mm^2 and the energy errors are in between -0.3 to 0.8%, which is considerable.
• CASE 7 -- Law 27(PLAS_BRIT) Produces internal stress of 362.1 N/mm^2 and the energy errors are in between -0.3 to 4.4% which is not recommended.
• The mass errors are 0% for every Law.

From the above discussion, CASE 6(PLAS_TAB) and CASE 3(PLAS/JOHNS) are preferred.

### SIDE CRASH ANALYSIS OF CHRYSLER S NEON Sachin M · 2019-10-31 05:44:44

SIDE CRASH OF CHRYSLER NEON The Chrysler Neon is a front-engine, front-wheel-drive compact car introduced in January 1994 for the model year 1995 by Chrysler\'s Dodge and Plymouth divisions in two and four-door body styles over two generations. BIW : BIW (Body in Whi Read more

### FRONTAL CRASH ANALYSIS OF CHRYSLER S NEON MODEL Sachin M · 2019-10-31 04:40:26

FRONTAL CRASH OF CHRYSLER NEON The Chrysler Neon is a front-engine, front-wheel-drive compact car introduced in January 1994 for the model year 1995 by Chrysler\'s Dodge and Plymouth divisions in two and four-door body styles over two generations. BIW : BIW (Body in Read more

### Comparison of different Contact Interface Cards for Crash tube and the Behaviour of the Material Sachin M · 2019-10-22 07:48:07

Objective :   To mesh the given bumper model using Hypermesh and simulate crash tube with different contact interface type using Radioss. Explanation : The given Bumper is meshed under given conditions.                 Read more

### Crash Worthiness of Rail Elements Using Hypermesh and Radioss Sachin M · 2019-09-20 10:01:34

1.Objectives:      To compare the result of the base simulation and improve shell element properties. 2.Explanation :   2.1 Simulation 1 : First, 0000.rad file is imported to the Hypermesh. To get a minimum of 25 animation files, frequency is Read more

### 2-D Meshing Of A Given Model using Hypermesh Sachin M · 2019-09-17 05:41:53

Objective:     The aim of this project is to do a geometry clean up for given models and perform 2D mesh using the midplane surface extract for the given parameters for the shell element. Procedure: Import the given model to Hypermesh --- Radioss. The Rad Read more

### File Parsing using Python Sachin M · 2019-09-14 04:42:56

Objective :    The aim of this project is do file parsing using python for different data provided in the file. Explanation:    File Parsing :         Text parsing is a common programming task that splits the given s Read more

### Curve Fitting of Linear and Cubic Polynomial Equation using Python Sachin M · 2019-09-13 14:21:00

Objective :      The main aim of the task is to perform a curve fit for linear and cubic polynomials equation and to find which curve fits the best to the actual data curve. Explanation :            The main aim of the cur Read more

### MESHING OF FRONT PANNEL AND HEMMING PROCESS Sachin M · 2019-09-12 07:13:09

Objective:   The main objective the process is to mesh the given hood model using ansa and do the hemming process at last. Hemming:    The hemming process is used in many automation where it helps to join two different surfaces with different material Read more

### Constraint Minimization-Pen and Paper Calculation Sachin M · 2019-09-11 05:46:50

f(x) = 5-(x-2)^2 - 2(y-1)^2        5 - x^2-4+4x-2y^2-2+4y = 0        -x^2-2y^2+4x+4y-1=0          g(x)=f(x)+λ g(x) = -x^2-2y^2+4x+4y-1 + λ (x+4y-3)   `(del g)/(d Read more