The second Bianchi identity is a well-known and fundamental
differential identity which holds on any smooth (semi-)Riemannian
manifold. In general relativity, due to the relation of the curvature
tensor and the energy-momentum tensor via the Einstein equations, this
identity then naturally implies energy and momentum conservation for
matter fields. What happens in situations where curvature singularities
associated with timelike singularities occur and the classical Bianchi
identity no longer makes sense? In this talk we establish a
distributional version of the contracted Bianchi identity, and
investigate for which matter fields this identity holds. Surprisingly,
the well-known Reissner-Weyl-Nordström spacetime of a single point
charge does not belong to this class, but other electromagnetic theories
and certain perfect fluids with one-dimensional timelike singularities
satisfy the second Bianchi identity weakly. Joint work with Michael
Kiessling and Shadi Tahvildar-Zadeh.