Dynamic joint identification of a resilient insert: substructure frequency response functions

The dataset contains numerical and experimental frequency response function (FRF) data of substructures for dynamic joint identification. Both the numerical and experimental datasets consist of FRFs of substructures A and B, as well as the assembly AJB. The numerical dataset contains FRFs of five AJB assemblies with different joints, while the experimental dataset contains assembly FRFs corresponding to a single joint.

The numerical FRF data is obtained by forming finite element method (FEM) models of substructures A, J, and B, where aluminum material properties are assigned to A and B, while the joint (J) material properties resemble a rubber-like material. Mode superposition is used to synthesize the numerical FRFs.

The experimental FRFs are obtained via impact excitation of substructures A, B, and the assembly AJB, where A and B are made of aluminum, while the joint (J) insert between A and B is 3D-printed using a TPU filament. Substructure excitation is performed using a modal impact hammer, while the response is measured using accelerometers. The H1 FRF estimator is used to estimate the FRFs of all substructures.

All FRFs are expressed in accelerance form. FRFs of a single substructure are stacked into an admittance matrix of shape: (N_f, N_o, N_i), where N_f is the number of frequency lines, N_o is the number of response (output) degrees of freedom (DoFs), and N_i is the number of excitation (input) DoFs. The last nine output and input DoFs of A and first nine output and input DoFs of B are considered as the interface DoFs. The interface DoFs can be transformed to a set of three translational and three rotational DoFs using the virtual point transformation (VPT).

The numerical FRF data, as well as response and excitation DoF location and orientation data are included in the file "numerical.h5", while the experimental data is included in the file "experimental.h5". Both are organized as follows:

- group "frequency" contains the discrete frequencies at which the FRFs are evaluated
- groups "Y_A" and "Y_B" contain the admittance matrices of substructures A and B, respectively

- groups "chn_A", "chn_B", "chn_AJB" contain the response DoF locations and directions of substructures A, B, and AJB, respectively
- groups "imp_A", "imp_B", "imp_AJB" contain the excitation DoF locations and directions of substructures A, B, and AJB, respectively
- groups "vp_chn_A", "vp_chn_B", "vp_chn_AJB" contain the response DoF data for VPT
- groups "vp_imp_A", "vp_imp_B", "vp_imp_AJB" contain the excitation DoF data for VPT

The two datasets differ only in assembly FRF data:
- in "experimental.h5", group "Y_AJB" contains the admittance matrix of the assembly AJB (in mm/s²/N)
- in "numerical.h5", group "Y_AJB_i" contains the admittance matrix of the assembly AJB pertaining to joint i
(i ∈ {1, 2, 3, 4, 5}) (in mm/s²/N).

3D models of substructures A, B, and AJB are also provided as STL files in the same coordinate system as response and excitation locations.