I currently have a model of a stainless steel cylinder and have used the linear static frequency analysis to inspect some of the structures vibrational frequencies. 

Eventually I want to load the inside of the cylinder with different pressure values, from experiments I know that increasing interal pressure causes an increase in the vibrational frequencies of the structure (even when the sample plastically deforms). Which type of analysis is best for this, considering that stainless steel is a non-linearly elastic material with a small linear region at the beginning of the stress-strain curve?

Thanks in advance.