Modern aerospace engineering constantly pushes the boundaries of launch vehicle design. To maximize payload capacity and minimize launch costs, structural engineers strive to reduce the dry mass of rockets. This optimization leads to highly flexible structures.
: Engineers typically use Finite Element Models (FEM) to represent the vehicle's dry structure. These models must account for the changing mass and stiffness as propellant is consumed during flight. dynamics and simulation of flexible rockets pdf
Rockets are commonly represented structurally using beam theories: Euler-Bernoulli Beam Theory: dynamics and simulation of flexible rockets pdf