Structural design optimization of CFRP chopper disks

Chopper disks are commonly used in neutron Time-of-Flight (TOF) spectroscopy. Such disks have one or more cut-outs and rotate around an axis parallel to the neutron beam, reaching operational speeds of up to 380Hz. In order to achieve an increase in rotational speed, three aspects were investigated. First, the impact of mass distribution on the dynamical behavior of the disk was studied. Second, the radial displacement of the disk was analysed and the disk was afterwards numerically optimized for lower widening around the central drilling. Finally, stress concentrations around the bottom of the cut-outs were calculated and the shape of the cut-outs was optimized in order to lower failure indices. Dynamic and strength tests were performed, which confirmed the numerically determined results. Due to all numerical optimizations being made, the maximum rotational speed of the chopper disk could in total be increased by 25%.