The optimal design of structural stiffness for the CEPC vertex detector supports based on a multi-objective genetic algorithm

Purpose The high-precision detection of vertex detectors in the circular electron positron collider (CEPC) has been a research focus in high-energy physics. However, the vibration characteristics of these detectors under external excitations have not been thoroughly studied.
Methods To achieve extremely high spatial resolution, the vertex detector supports (hereafter referred to as the supports) are designed to be lightweight and thin. This study employs theoretical analysis and numerical simulation methods, proposing a multi-objective genetic algorithm to optimize the structural stiffness. The optimized structure is validated through modal analysis and computational fluid dynamics.
Results The inner and middle supports exhibit good rigidity, with the first natural frequency exceeding 100 Hz. However, the first natural frequency of the outer support is less than 100 Hz. When subjected to cooling fluid impacts at a flow rate of 4 m/s or higher, this can easily lead to structural resonance. At airflow rates of 2 m/s and 3 m/s, the ratio of the excitation frequency to the natural frequency of the structure exceeds 0.6, resulting in significant vibration amplification.
Conclusion The outer support exhibits significant vibration amplification under the impact of cooling airflow at different speeds. By optimizing the structural dimensions and cooling airspeed while ensuring lightweight and structural integrity, this study effectively mitigates the vibration amplification phenomenon in the outer support induced by fluid excitation.