Estimation of the rivet-squeezing force based on dynamic response - small dataset

The dataset contains dynamic response measurements, in the form of frequency response functions (FRFs), of multiple structures:
- of the metal sheet plates A and B (Structure_images.jpg), which were joined together over the riveted joint;
- of the dynamic responses of the assembled systems.

Components A and B were joined together in two different configurations of the assembled system - ARB, and A'RB' (Structure_images.jpg). Each of the assemblies has been joined multiple times, each time with a different rivet-squeezing force. The dynamic response has been measured for the following squeezing force values:

- for assembly ARB: 5 kN, 8.3 kN, 9.2 kN, 10 kN, 10.8 kN, 11.7 kN, and 15 kN;
- for assembly A'RB': 8.3 kN, 10.8 kN, 15 kN.

These data can be used to isolate the dynamic models of the riveted joints, using the dynamic substructuring principles. This allows us to observe how the riveting squeeze force affects the dynamic response of the joint for different assemblies.

The data, containing information about the dynamic responses of individual structures/assemblies, as well as the locations and directions of the observed/controlled response/excitation degrees of freedom (DoFs), is stored in data.h5 file, which is organized as follows:

- The main group is named 'data'.
+ 'data' group contains 7 subgroups:
* Group 'freq_Hz' that contains a list of discrete frequency points in Hz;
* 6 groups - one for each type of dynamic model (A, A_alt, B, B_alt, ARB, ARB_alt).

There are two models for A (A, A_alt) and B (B, B_alt) because different sets of DoFs were measured for assembly ARB (group ARB) and A'RB' (group ARB_alt) to provide a collocated set of DoFs, required for dynamic decoupling.

Each of the 4 groups related to structures A and B is organized as follows:
- Group contains 3 subgroups: impact_dofs, response_dofs, and FRFs. Impact_dofs and response dofs contain lists of observed excitation and response DoFs, described as: (x-coordinate, y-coordinate, z-coordinate, direction 1, direction 2, direction 3). Dimensions are in meters. The origin of the coordinate system is located at the location where the structure is to be linked to the adjacent component (middle of red/blue circle in Structure_images.jpg). Direction 1 denotes the x-axis (1 for positive x, -1 for negative), direction 2 denotes the y-axis, and direction 3 denotes the z-axis (Structure_images.jpg). The FRFs group contains a subgroup for each FRF, described as {excitation_dof}_{response_dof}. Each such subgroup contains separate lists of real and imaginary parts of the FRF (named 'real' and 'imag', respectively).

Each of the remaining two groups for assemblies ARB and A'RB' (named ARB and ARB_alt, respectively) contains a subgroup for each squeezing force level, and then the organization is the same as for components A and B (impact_dofs, response_dofs, and FRFs subgroups for each squeezing force level).