I want to get Johnson-Cook model for 3 septicemic in the same size and dimensions.

I want to get Johnson-Cook model for 3 septicemic in the same size and dimensions. will be enough or I should play in the thickness of my septicemic?I saw numbers of papers play in the diameter (Obtaining Constants of Johnson-Cook MaterialModel Using a Combined Experimental, NumericalSimulation and Optimization MethodF. Rahimi Dehgolan, M. Behzadi, J. Fathi Sola)but my samples are flat. so what should I do?