Superplastic Cone-Shaped Sandwich Cores

A new sandwich core is formed by using the superplastic sheets and the vacuum pressure- or gas pressure-forming technique, or both. It is capable of providing opportunities for structural optimization and better bonding with the facing sheets than the conventional honeycomb core. The shear modulus of a truncated, hollow, cone-shaped core with square symmetry is determined. Energy principles are used for finding the upper and lower bounds solution. Results presented in graphic form indicate that these bounds are indeed very close. The methodology developed here is effective for providing an excellent engineering solution to the problem. The new superplastically-formed core also offers a competent approach for those who seek a more efficient metallic structural design, particularly when it is used in combination with the difussion bonding technique for weight and cost savings.