Next-generation test methods for nonlinear structures

许多物理系统，无论是工程的还是自然的，都会随着物理参数的变化而发生突然的行为变化。例子包括摩托车的车轮摆振（“打坦克”），前轮在临界速度下开始剧烈振荡，飞机的气动弹性颤振，机翼在临界风速下开始振动和变形。基于控制的延拓（CBC）是一种在物理实验中直接研究这些类型的非线性动力学和分岔的方法，而不需要首先推导系统的数学描述。该提案旨在将CBC推进到可以成为结构工程师使用的通用工具的程度（从长远来看，更广泛地用于工业家和应用科学家）。具体来说，这一建议涉及到CBC的两个方面。首先，对噪声的鲁棒性；任何物理系统都会受到干扰（噪声）的影响，有些干扰的程度比其他的要高，而CBC必须能够处理这些干扰。其次，具有多自由度的可扩展性；物理结构和系统不一定简单，可能有许多相互作用的组件，CBC必须很好地扩展到大型结构。

Many physical systems, whether engineered or natural, undergo sudden changes in behaviour as a physical parameter changes. Examples include the onset of wheel shimmy ("tank-slapping") in motorbikes, where the front wheel starts to oscillate violently at a critical speed, and aero-elastic flutter in aeroplanes, where an aerofoil starts to vibrate and deform at a critical wind speed. Control-based continuation (CBC) is a method for investigating these types of nonlinear dynamics and bifurcations directly in physical experiments without the need for first deriving a mathematical description of the system. This proposal seeks to advance CBC to the point where it can become a general-purpose tool for use by structural engineers (and in the longer term, wider ranging use by industrialists and applied scientists). Specifically, two aspects of CBC are addressed in this proposal. Firstly, the robustness to noise; any physical system is subject to disturbances (noise), some to higher degrees than others, and CBC must be capable of dealing with these disturbances. Secondly, the scalability to multiple degrees of freedom; physical structures and systems are not necessarily simple and may have many interacting components, CBC must scale well to large structures.