The dynamic responses of assembled structures are greatly affected by the mechanical joints, which are often the cause of nonlinear behavior. To better understand and, in the future, tailor the nonlinearities, accurate methods are needed to characterize the dynamic properties of jointed structures. In this paper, the nonlinear characteristics of a jointed beam is studied with the help of multiple identification methods, including the Hilbert Transform method, Peak Finding and Fitting method, Dynamic Mode Decomposition method, State-Space Spectral Submanifold, and Wavelet-Bounded Empirical Mode Decomposition method. The nonlinearities are identified by the responses that are measured via accelerometers in a series of experiments that consist of hammer testing, shaker ringdown testing, and response/force-control stepped sine testing. In addition to accelerometers, two high-speed cameras are used to capture the motion of the whole structure during the shaker ringdown testing. Digital Image Correlation (DIC) is then adopted to obtain the displacement responses and used to determine the mode shapes of the jointed beam. The accuracy of the DIC data is validated by the comparison between the identification results of acceleration and displacement signals. As enabled by full-field data, the energy-dependent characteristics of the structure are also presented. The setup of the different experiments is described in detail in Part I (Chen et al., 2021) of this research. The focus of this paper is to compare nonlinear system identification methods applied to different measurement techniques and to exploit the use of high spatial resolution data.

组装结构的动态响应受机械接头的影响很大，这通常是非线性行为的原因。为了更好地理解并在未来调整非线性，需要使用准确的方法来表征关节结构的动态特性。本文借助希尔伯特变换法、寻峰拟合法、动态模态分解法、状态空间谱子流形和小波有界经验模态等多种识别方法研究了连接梁的非线性特性。分解法。非线性是通过在一系列实验中通过加速度计测量的响应来识别的，这些实验包括锤击测试、振动器振铃测试和响应/力控制步进正弦测试。除了加速度计之外，还使用两个高速摄像机来捕捉振动台振铃测试期间整个结构的运动。然后采用数字图像相关 (DIC) 来获得位移响应并用于确定连接梁的模式形状。通过加速度和位移信号识别结果的对比，验证了DIC数据的准确性。在全场数据的支持下，还介绍了结构的能量相关特性。本研究的第一部分（Chen 等，2021）详细描述了不同实验的设置。本文的重点是比较应用于不同测量技术的非线性系统识别方法，并利用高空间分辨率数据。两台高速摄像机用于在振动台振铃测试期间捕捉整个结构的运动。然后采用数字图像相关 (DIC) 来获得位移响应并用于确定连接梁的模式形状。通过加速度和位移信号识别结果的对比，验证了DIC数据的准确性。在全场数据的支持下，还介绍了结构的能量相关特性。本研究的第一部分（Chen 等，2021）详细描述了不同实验的设置。本文的重点是比较应用于不同测量技术的非线性系统识别方法，并利用高空间分辨率数据。两台高速摄像机用于在振动台振铃测试期间捕捉整个结构的运动。然后采用数字图像相关 (DIC) 来获得位移响应并用于确定连接梁的模式形状。通过加速度和位移信号识别结果的对比，验证了DIC数据的准确性。在全场数据的支持下，还介绍了结构的能量相关特性。本研究的第一部分（Chen 等，2021）详细描述了不同实验的设置。本文的重点是比较应用于不同测量技术的非线性系统识别方法，并利用高空间分辨率数据。