Integrated modeling and stiffness regulation of SMA-based aeroengine variable stiffness bracket

Aeroengine brackets must fulfill two conflicting requirements: high load-bearing stiffness and effective vibration isolation flexibility. This challenge centers on the scientific problem of real-time structural stiffness regulation. This paper presents the design and realization of a smart bracket with active variable stiffness capability. By combining modeling with experimental analysis, we developed a methodology for regulating and measuring the stiffness of complex truss structures. Leveraging the phase transformation characteristics of shape memory alloy, a novel bracket was designed with SMA plates serving as its key supporting components. An integrated model of the aeroengine casing-bracket-accessory system was established to simulate its stiffness variation under realistic operational scenarios. Simulation results show a reversible stiffness increase of 22.6% over the range 40–100 ℃, with a highly symmetric mechanical response. We developed an insulation-encapsulated heating strategy and implemented a novel multi-sensor cooperative measurement scheme to achieve quantitative characterization of the bracket’s equivalent stiffness. Experimental validation further revealed the complex dynamic behavior of SMA within real structures. The bracket’s stiffness increased by up to 30.67%. Furthermore, a significant thermo-mechanical hysteresis was observed. Completing the full transformation took approximately 66% longer than merely reaching the transformation temperature. This work provides crucial design principles and methodological support for developing intelligent connection structures and active vibration control technologies for aeroengines.