Where 𝐸𝐸 � is the plane strain modulus, 𝐸𝐸 � = 𝐸𝐸/(1 -𝜈𝜈 2 ), and 𝜇𝜇 is the shear modulus, 𝜇𝜇 = 2𝐸𝐸/(1 + 𝜈𝜈). The only two length scales present in this problem are the film thickness and the crack length. According to Nakamura and Kamath , in the limit that the crack length is larger than the film thickness, the strain energy release rate (and thus stress intensity factor) is independent of crack length. This allows us to invoke the analysis from Beuth to estimate the steady state energy release rate (𝐺𝐺 𝑒𝑒𝑒𝑒. ) for a uniform stress 𝜎𝜎 on the crack face: