Shear Stiffness in x-Direction

D_{44, c a l c}^{"} = \frac{1}{\int_{- t / 2}^{t / 2} \frac{G_{22}^{"} (z)}{G_{11}^{"} (z) G_{22}^{"} (z) - {G_{12}^{"}}^{2} (z)} (^{\frac{\int_{z}^{t / 2} E_{x}^{"} (\bar{z}) (\bar{z} - z_{0, x}) d \bar{z}}{\int_{- t / 2}^{t / 2} E_{x}^{"} (\bar{z}) {(\bar{z} - z_{0, x})}^{2} d \bar{z}}) 2} d z}

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