  We present a detailed analysis of the molecular packing of a strained liquid
crystal elastomer composed of chiral mesogens in the smectic A phase. X-ray
diffraction patterns of the elastomer collected over a range of orientations
with respect to the X-ray beam were used to reconstruct the three-dimensional
scattering intensity as a function of tensile strain. For the first time, we
show that the smectic domain order is preserved in these strained elastomers.
Changes in the intensity within a given scattering plane are due to
reorientation, and not loss, of the molecular order in directions orthogonal to
the applied strain. Incorporating the physical parameters of the elastomer, a
nonlinear elastic model is presented to describe the rotation of the
smectic-layered domains under strain, thus providing a fundamental analysis to
the mechanical response of these unique materials.
