Spatial Applicability of Fictitious Point Feedback for Frequency Response Prediction in Unidirectional Carbon Fiber-Reinforced Polymer Plates

Fiber orientation and anisotropy change the spatial vibration response of carbon fiber-reinforced polymer (CFRP) plates, potentially limiting prediction from a single driving-point frequency response function (FRF). This retrospective study assesses fictitious feedback using complex mobility FRFs measured by laser vibrometry at 15 locations for seven CFRP orientations and a thicker matrix-only specimen. One specimen and one averaged FRF dataset were analyzed per configuration. A frequency-dependent scalar was calibrated at P8, with 14 outputs reserved for validation. All 42 directed CFRP comparisons were evaluated using complex error, spatial correlation, and frequency coverage. Within 100–1000 Hz, 28 comparisons exceeded 100% error. The lowest error, 18.2% for 90–75°, covered 36.8% of frequency lines and 26.9% of validation cells, and 96.8% of retained squared target-response amplitude lay within 200–300 Hz. The same comparison gave 45.3% without rescaling and 40.2% with a constant P8-fitted scalar, but local errors exceeded 90%. The frequency-dependent scalar outperformed the constant scalar in only 14 of 42 primary-band comparisons. These observations define conditional scalar-transfer limitations for the tested specimens and support arrangement. They do not establish prospective accuracy at unmeasured outputs or isolate fiber orientation from specimen and support effects.