Hi, I’m trying to model a simply supported square cross-ply (00/900 and 00/900/00) laminated plate and subjected to thermal gradient in ABAQUS, I have to trace the normal stress (Sxx, Syy ie S11,S22, S13); Transvers shear stress (Sxz, Syz) and displacements.
I’m modeling this by using Continuum shell; Homogenous section (SC8R element).
Please check the following ERROR message is displayed by ABAQUS.
“Stiffness defined by type=LAMINA is not physically reasonable. The total work done by all strain components must be positive. Check choice of poisson’s ratio. An invalid set of property value has been specified for *ELASTIC, TYPE=LAMINA. The value of [1.0 – (E2/E1) * Nu12**2] must be greater than zero. The specified set of E1=10000, E2=150000, and Nu12=0.30 does not meet this criteria”
Following material properties defined for each ply (0,90,0):
Material for ply-1: E1=150000, E2=10000, and Nu12=0.30, G12=5000, G13=5000, G23=3356
Material for ply-2: E1=10000, E2=150000, and Nu12=0.30, G12=5000, G13=3356, G23=5000
Material for ply-3: E1=150000, E2=10000, and Nu12=0.30, G12=5000, G13=5000, G23=3356
Please check the material properties defined for 1 and 2 material after conversion/transfer of zero degree to 90 degree material orientation, as shown above.
Thanks and regards,
Omprakash
The answer is already described in the error message.
In highly anisotropic material, the Poisson ratio must be quite small. There are relationships between the modulus and the Poisson ratios. In following publication, the relationship is described.
https://www.researchgate.net/publication/308940405_Stress_redistribution_as_an_effect_of_non-uniform_in-plane_laminate_stresses_in_laminate_composite_plates?_iepl%5BviewId%5D=QtlJK60VsPLmSBWLPgIelMLg&_iepl%5BprofilePublicationItemVariant%5D=default&_iepl%5Bcontexts%5D%5B0%5D=prfpi&_iepl%5BinteractionType%5D=publicationTitle
Article Stress redistribution as an effect of non-uniform in-plane l...
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