Student : Kalyan Nadella
Sponsor : NASA Constellation University Institutes Projects / Advanced Composites Technologies Program
A complete 3D-elasticity based formulation becomes extremely complicated for modeling sandwich structures because of the interface conditions and accounting the shape of the unit cells in the formulation and Traditional numerical tools such as FEM inefficient due to large computational cost associated with small wavelength discretizations. So, a numerical method is being implemented to model the composite structures.
The LISA method is based on iterative equations (IE) for “unit cells” that are used to represent/discretize the model as shown in figure below.
The actual IEs are derived from the elastodynamic equilibrium equations. The coefficients in these iterative equations depend only on the local physical properties.
Continuity of displacements and stresses are enforced at the interface between the cells (sharp interface method). Therefore, changes in stiffness, density, or attenuation can be accounted for as the IE coefficients in adjacent cells with different properties will be different.
Objectives of the project are to develop a working and robust 2-D and 3-D modeling to analyze guided wave propagation in complex composite structures like honeycomb composite structures.