SANDWICH SHELL INITIALIZATION
Altair EmployeeHi,
I am solving one crash analysis, i received the following warning message,
WARNING ID : 519
** WARNING IN SANDWICH SHELL INITIALIZATION
DESCRIPTION :
-- PROPERTY ID : 8100003
-- PROPERTY TITLE : Windshield
SHELL ID=3664432 MASS
SUM OF LAYER MASS(0.6913370997374E-06) DIFFERS FROM TOTAL(0.7407183211472E-06)
can you please suggest me a solution
Answers
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Hi,
These messages concern a shell element using a Type 11 property (“sandwich shell”).
They mean that the mass (or inertia) of the shell, as it is computed from the characteristics of each layer (position, thickness, associated material), is not equal to the mass (or inertia) which is computed from the global material associated to the PART and the total thickness of the shell given in the property type 11.
The stability time step is computed from the global characteristics of the shell; it can not be ensured if the mass and inertia computed for the shell are not close enough to the mass and inertia which is computed from the density of the global material and the total thickness given in the shell property. So these messages are written if the relative error with respect to the mass (or inertia) computed from the global characteristics is greater than 1%. In order to ensure the stability, it is recommended to set a Young modulus for the global material, at least equal to the maximum modulus of the materials associated to all layers.
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Altair Forum User said:
Hi,
These messages concern a shell element using a Type 11 property (“sandwich shell”).
They mean that the mass (or inertia) of the shell, as it is computed from the characteristics of each layer (position, thickness, associated material), is not equal to the mass (or inertia) which is computed from the global material associated to the PART and the total thickness of the shell given in the property type 11.
The stability time step is computed from the global characteristics of the shell; it can not be ensured if the mass and inertia computed for the shell are not close enough to the mass and inertia which is computed from the density of the global material and the total thickness given in the shell property. So these messages are written if the relative error with respect to the mass (or inertia) computed from the global characteristics is greater than 1%. In order to ensure the stability, it is recommended to set a Young modulus for the global material, at least equal to the maximum modulus of the materials associated to all layers.
thank you George, it was very helpfull
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