CMS ECAL Barrel, Submodule's Deformation during Module Assembly

During module assembly, submodules ( modular alveolar structures in CMS ECAL Barrel, each containing 10 crystals) are bolted to the grid ( module support structure) and cantilevered with a max. angle of 18¡. In order to investigate the deformations, the system was reduced to Timoshenko beams connected to the grid by rotary springs and loaded by rigid crystals ( concentrated load). The deformation of single submodules as well as the deformation of the submodule assembly in the case of shimming were studied. In the latter case the resulting non linear equation system was solved by an iteration. Different extreme cases were calculated since not all stiffness parameters needed for the Timoshenko beam were available.