Optimization of vibration test fixture based on a fixed grid to maximize natural frequency using a genetic algorithm

Automotive components are continuously exposed to vibration during operation, making vibration testing essential for durability evaluation. Vibration test fixtures mount specimens onto testing systems and transmit dynamic loads to them. The accuracy and reliability of the test results are affected by the dynamic characteristics of the fixture. However, conventional methods often produce fixtures with low natural frequencies and excessive mass, inducing unwanted resonance. To overcome these limitations, this study proposes a fixed grid-based optimization framework for vibration test fixtures. This method generates a finite element model using a fixed-grid representation of the design space to optimize the rib height and surface existence using a genetic algorithm. Numerical validation demonstrated that the optimized fixture achieved a mass of 113.5 kg and a fundamental natural frequency of 496.8 Hz. Compared with the conventionally optimized reference model, the proposed method reduced the mass by 20.9% and increased the natural frequency by 2.29%. Furthermore, the computational time was decreased from approximately 15 h to 6.5 h, improving computational efficiency by 56.7%. These results indicate that the proposed framework can develop lightweight and high-stiffness vibration test fixtures.