Explicit Dynamics Jun 2026

That tiny step isn't a bug; it's the physics. You are literally simulating the propagation of a stress wave across your model. For a steel beam being hit by a projectile, that wave moves fast. To capture it, you must move faster.

Notice that the solution for $u_n+1$ relies only on quantities known at time steps $n$ and $n-1$. The stiffness matrix ($K$) does not need to be inverted. This is typically solved using a "Lumped Mass Matrix" (diagonal mass matrix), where the inversion of $M$ is trivial. explicit dynamics

Because there is no matrix inversion, explicit methods are incredibly robust at handling severe non-linearities—provided you use a very small, stable time step. That tiny step isn't a bug; it's the physics