DA11_Park 2*c/(I0c/intop3(shell.DA11)+I0s/(5/6*intop3(shell.DAs11))+I2/intop3(shell.DD11)) "Equivalent extensional stiffness matrix, 11-component" DA12_Park intop3(shell.DA12/shell.DA11)*DA11_Park "Equivalent extensional stiffness matrix, 12-component" DA22_Park intop3(shell.DA12)*DA12_Park/intop3(shell.DA11)+lh/c*intop3((shell.DA11*shell.DA22-shell.DA12^2)/shell.DA11) "Equivalent extensional stiffness matrix, 22-component" DA33_Park c/lh*intop3(shell.DA33) "Equivalent extensional stiffness matrix, 33-component" DD11_Park c/lh*intop3(shell.DD11) "Equivalent bending stiffness matrix, 11-component" DD12_Park intop3(shell.DD12/shell.DD11)*DD11_Park "Equivalent bending stiffness matrix, 12-component" DD22_Park 1/(2*c)*(I2*intop3(shell.DA22)+I0c*intop3(shell.DD22)) "Equivalent bending stiffness matrix, 22-component" DD33_Park lh/c*intop3(shell.DD33) "Equivalent bending stiffness matrix, 33-component"