  An error control technique aimed to assess the quality of smoothed finite
element approximations is presented in this paper. Finite element techniques
based on strain smoothing appeared in 2007 were shown to provide significant
advantages compared to conventional finite element approximations. In
particular, a widely cited strength of such methods is improved accuracy for
the same computational cost. Yet, few attempts have been made to directly
assess the quality of the results obtained during the simulation by evaluating
an estimate of the discretization error. Here we propose a recovery type error
estimator based on an enhanced recovery technique. The salient features of the
recovery are: enforcement of local equilibrium and, for singular problems a
"smooth+singular" decomposition of the recovered stress. We evaluate the
proposed estimator on a number of test cases from linear elastic structural
mechanics and obtain precise error estimations whose effectivities, both at
local and global levels, are improved compared to recovery procedures not
implementing these features.
