StaffStress
Aerospace
- Nov 11, 2004
- 8
Hi all, I'm a frequent reader but this is the first question I've posted. I have severe confusion regarding stiffness values to use for MAT2 card 2D anisotropic manual material input in Nastran/Patran.
I need to evaluate a membrane material card and a bending material card for a particular laminate. The MAT2 input fields are G11, G12, G13, G22, G23, G33.
Nastran user guide is rather incomplete in defining the equations for the Gij values for membrane material and also for the bending material and which matrix, i.e. reduced stiffness or rotated reduced stiffness, to use. The literature typically defines these matricies as [Q] and [Q-bar] respectively and not as [G]. I asume for the bending material the [D] matrix must be involved??
Questions are, which of the stiffness matricies from CLT is appropriate to use for the Gij's (Qij or Qij-bar)?
How do the stiffness calcs for Gij differ for the membrane material vs. the bending material?
Regards.
I need to evaluate a membrane material card and a bending material card for a particular laminate. The MAT2 input fields are G11, G12, G13, G22, G23, G33.
Nastran user guide is rather incomplete in defining the equations for the Gij values for membrane material and also for the bending material and which matrix, i.e. reduced stiffness or rotated reduced stiffness, to use. The literature typically defines these matricies as [Q] and [Q-bar] respectively and not as [G]. I asume for the bending material the [D] matrix must be involved??
Questions are, which of the stiffness matricies from CLT is appropriate to use for the Gij's (Qij or Qij-bar)?
How do the stiffness calcs for Gij differ for the membrane material vs. the bending material?
Regards.