  Mass lumping techniques are commonly employed in explicit time integration
schemes for problems in structural dynamics and both avoid solving costly
linear systems with the consistent mass matrix and increase the critical time
step. In isogeometric analysis, the critical time step is constrained by
so-called "outlier" frequencies, representing the inaccurate high frequency
part of the spectrum. Removing or dampening these high frequencies is paramount
for fast explicit solution techniques. In this work, we propose robust mass
lumping and outlier removal techniques for nontrivial geometries, including
multipatch and trimmed geometries. Our lumping strategies provably do not
deteriorate (and often improve) the CFL condition of the original problem and
are combined with deflation techniques to remove persistent outlier
frequencies. Numerical experiments reveal the advantages of the method,
especially for simulations covering large time spans where they may halve the
number of iterations with little or no effect on the numerical solution.
