报告题目：Complex Dynamics of Vibroimpact Systems

报 告 人：Daniil Yurchenko教授（英国南安普顿大学）

报告时间：2026年7月7日（周二）9:30-10:30

报告地点：龙洞校区教学楼316

主 持 人：杨勇歌

报告摘要：Vibroimpact (VI) systems combine continuous vibration with sudden impacts, producing strong energy transfer and complex non-smooth dynamics. A particularly important phenomenon is grazing bifurcation, which occurs when a trajectory becomes tangent to the impact boundary, leading to a zero-velocity impact and a sudden qualitative change in system behaviour. This presentation examines the dynamics of a vibroimpact pair in which a freely moving ball collides with dielectric membranes inside a harmonically excited capsule. The impacts deform the membranes, change their capacitance and enable vibration energy harvesting. The stability of diKerent motion regimes and transitions between them are analysed, with particular attention to the interaction between ghost period-doubling and grazing bifurcations. The same system is also considered as a vibroimpact nonlinear energy sink (VI-NES), where targeted energy transfer is used to mitigate excessive vibrations. Although increasing the mass ratio may appear beneficial, its influence is more complex and can sometimes reduce mitigation performance. An exact-map computational framework is used to investigate periodic and chaotic regimes, including stable and unstable solution branches, and to reveal features that are diKicult to identify using conventional numerical methods. Finally, a new approach to global stability analysis is introduced. Since classical Lyapunov-exponent methods are diKicult to apply directly to non-smooth systems, the proposed method reduces the global dynamics to a cobweb-type analysis, providing a clearer representation of the system’s long-term behaviour.

报告人简介：英国南安普顿大学教授，研究方向主要包含非线性和随机动力学、控制理论、振动、稳定性和分叉分析、以及能量俘获等。已发表100余篇学术论文，主持多个工业项目、英国工程和自然科学研究委员会和英国皇家学会的科研项目。《Mechanical Systems and Signal Processing》《International Journal of Dynamics and Control》《Vibrations》《Journal of Vibration Testing and System Dynamics》等国际期刊编委。