SN curve(s) of an anisotropic material
I was just wondering how many S-N curves would i need to define the fatigue properties of an anisotropic material. For an isotropic material we just use 1-curve. Would that also be enough for an anisotropic material? We need 21 elastic constants to define anisotropic material. Would the number of SN curves be similar or be somehow related to the number or would the number of S-N curves required would be probabilistic in nature. i.e. we find the S-N curves along several planes and get a some sort of probabilistic distibution.
I have strung and unstrung my instrument,
but the song i came to sing remains largely unsung