Hello,
For cubic solids, the bulk modulus is expressed in terms of the elastic constants as K = (C11+2*C12)/3.
On the other hand, the bulk modulus is quoted as K = -V*dP/dV. This is somewhat confusing to me, since according to the first definition, the bulk modulus depends on direction. So, if I rotate my coordinate system by some amount, K will change (C11+2*C12 is not invariant under rotation).
However, this is not the case for the second definition, so it seems these are incompatible? Is the second definition simply valid for an isotropic material such as a fluid?
Thanks!
Bulk modulus anisotropy
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maartendft
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Bulk modulus anisotropy
Last edited by maartendft on Sat Aug 09, 2014 9:25 am, edited 1 time in total.
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support_vasp
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Re: Bulk modulus anisotropy
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