  We study the deflection and fluctuations of a clamped elastic fiber embedded
in 2D foam under quasistatic flow. At all times, the fiber conformation results
from the elasto-capillary interactions with the foam. We independently measure
the action of capillary and pressure forces on the fiber, and show that the
fiber deformation is adequately described assuming a uniform continuous normal
force acting on it. When bending energy exceeds a threshold value, the fiber
relaxes to a less deflected shape, generating a cascade of plastic
rearrangements within the foam, and the process repeats periodically. We
analyze the statistical distributions of stored and released energy, and
estimate the yield stress and shear modulus of the foam, as well as the number
of elementary plastic events involved in a cascade.
