Bullet impact simulation problem
Altair EmployeeDear all,
I'm facing with the simulation of the impact of a bullet on a steel plate. The bullet travels at 710 m/s and the plate is 6.3 mm thick. The bullet and the plate are simulated with solid element (BRICK). P14_SOLID is used for the solid and the johnson-cook material model (M2) is used for the steel plate and the bullet. The interface is a type7 vith bullet nodes as slave and plate as master.
Radioss return to me the error 'ZERO OR NEGATIVE VOLUME FOR 3D-ELEMENT'.
in PSOLID definition i've used both the Isolid option 1 and 24 and the Ismstr option 2 for large deformations but the error still remain. Does anyone could tell me something?
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Answers
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Hi Alessio,
The NEGATIVE VOLUME error happens when solid elements are very deformed and their characteristic length goes to 0. For large strain formulation the time step of an element goes to 0 when the element is compressed. In RADIOSS Starter input file (Runname_0000.rad), use Ismstr =2 in the solid property and in RADIOSS Engine file (Runname_0001.rad) use the option/DT/BRICK/CST which will set the time step value tmin at which the solid elements will switch to small strain.This means that the solid elements using Ismstr =2 will use large strain formulation while their time step remains greater than tmin, and will then switch to small strain formulation.
Please try with the attached model file.
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thanks George,
Do you think that type7 interface is good for this kind of simulation or there is some better way to simulate the interaction between bullet and plate. Because the bullet deformation during the impact is not so good.
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Hi Alessio,
I made some modifications in the model. Please check the files attached and let us know whether you are looking for a similar simulation.
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Hi George,
no i don't want to use a rigid body for the bullet... i'd like to simulate the real bullet which impact the plate. I would to see the bullet that hit the plate and becomes something like that in the pictures... Thanks for your help
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Hi Alessio,
In such a case the workaround possible is you can make the wall rigid and make the bullet to impact on the same so that the bullet will deform. It also depends on the material properties of the bullet and the geometry. And so ensure the material values are correct.
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thanks George. I'll try to apply different values for the material. I've just used some data form a work i've found on the internet.
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