A Multi-objective Optimization Method for Cantilever Truss Structure Combining Modal Tracking and Dynamic Load Response

Truss structures are commonly used in engineering due to their lightweight and efficient load-bearing characteristics, as they are primarily formed by assembling or welding basic members. In particular, the common hollow cantilever truss structure (HCTS) in engineering is subjected to the coupling effects of dynamic loads and vibration response, so it is necessary to find the corresponding optimal configuration. This paper aims to propose an optimization method for HCTS in engineering, based on coupled mode tracking and dynamic loads. First, the vibration experiment was completed, and the vibration characteristics were obtained. Next, specific vibration modes of the structure were tracked to formulate an optimization model for the maximum frequencies of particular orders. Also, based on the equivalent static load method and given dynamic loads, an optimization model for overall maximum stiffness was formulated. Subsequently, the multi-objective topology optimization model containing periodic manufacturing constraints was normalized. The topology result shows that the introduction of periodic constraints reduces the normalized value of the optimization objectives, but an appropriate number of cells balances structural performance and manufacturing difficulty. After simplifying the spatial structure, shape optimization was completed, and the optimal structure was verified. The result shows that, while maintaining the base mass, the optimal first and second order frequencies increase by 5.6% and 11.6%, respectively. Also, the maximum deformation under static loads decreases by 32.3%, validating the effectiveness of the optimization method proposed.