Tensile Test Lab Report

One element tensile test is conducted for element size of 5mm at strain rates mentioned in Fig. 7 7. The true stress versus plastic strain results of the simulation in comparison to the load curve is shown in Fig. 7 9. As the damage is coupled to the stress tensor by Eq. 4 1, there is a continuous reduction of stress. The plastic strain at failure for different strain rates is shown in Fig. 7 11 which is in accordance to the scaling factor given for different strain rates.
One element tensile test is also conducted for element size ranging from 1mm to 7mm at a constant strain rate of 1s-1. Element size dependent regularization factors for equivalent plastic strain to failure in the GISSMO model is inputted by means of LCREGD curve. A reasonable
7 9: True stress versus Plastic strain- One element tensile test Fig. 7 10: One element tensile test – Variation of element size
Two element formulations in *SECTION_SHELL namely the Belytschko-Tsay (ELFORM2) and fully integrated shell element (ELFORM16) were analysed for the one element tensile test at different strain rates. ELFORM16 is 10-20% faster compared to ELFORM2 and produces the same results as ELFORM2 as shown in Fig. 10 5.
Another investigation done in the one element tensile test is the variation of Young’s modulus between 0.9GPa to 1.9GPa. Increasing the Young’s modulus reduces the strain in the elastic and plastic region. This can be seen in Fig. 10 6.
In order to check the stability of the material model in different LS-DYNA versions, the one element simulation is conducted for two more versions namely SR511 and SR611. The test is conducted for different strain rates and for the element formulations 2 and 16. The true stress-plastic strain curve remains the same for the versions SR511 and SR611 in comparison to the results of version SR612. The results are shown in Fig. 10 7 and Fig. 10 8

Strain rate (s-1) Plastic strain at failure for one element simulation (-) Tensile test Compression
7 13. The specimen is modelled with shell elements of thickness 2mm. To simulate the tensile test, the nodes on the bottom end of the model were fixed in x, y and z directions, while the nodes on the top end of the model were given a constant velocity. The test is simulated under test velocities 0.00083m/s, 1m/s and 4m/s. The displacement of the test sample was obtained from the top side of the specimen, which was the same side as where the boundary condition with constant velocity was located. The force was obtained from a cross section of the test