Engineering Constants of Laminates — Lesson 2

This lesson covers the concept of laminate stiffness, focusing on special cases and how to eliminate undesirable characteristics. It explains the significance of making some elements of the BBD Matrix zero, such as eliminating bending extension coupling by making the B Matrix zero. The lesson also discusses how to evaluate the effective engineering constants for a laminate, characterized by the ABBD Matrix. It further explains how to determine the effective Young's modulus in extension and flexure, and the in-plane shear modulus for a symmetric laminate. The lesson concludes with the explanation of how to obtain the shear extension coupling for a general symmetric laminate.

Video Highlights

02:09 - Explanation of the ABBD Matrix and its elements
07:54 - Determination of the effective Young's modulus in extension
15:03 - Determination of the effective Young's modulus in flexure
22:56 - Explanation of the in-plane shear modulus for a symmetric laminate
32:29 - Effective in-plane shear modulus (Gxy) of a symmetric laminate
34:49 - Young's modulus in flexure along X and Y for a symmetric laminate

Key Takeaways

- The BBD Matrix plays a crucial role in understanding laminate stiffness. Making some elements of this matrix zero can help eliminate undesirable characteristics.
- The effective engineering constants for a laminate can be evaluated, which are characterized by the ABBD Matrix.
- The effective Young's modulus in extension and flexure, and the in-plane shear modulus for a symmetric laminate can be determined.
- For a general symmetric laminate, it is possible to obtain the shear extension coupling.