Parameter Investigation of Sensor Fixation Methods Compared with High-Quality Laser Measurement Using a Scalable Automatic Modal Hammer

The need to measure complex mechanical structures has grown in importance for efficiency in the design process and for structural monitoring. Despite the convenience of using a 3D scanning laser Doppler vibrometer (LDV), fixed acceleration sensors are still widely used for industrial applications. However, the effects of sensor attachments cannot be disregarded for lightweight structures. This paper provides a thorough description of how various sensor attachment techniques affect vibration measurements over a wide frequency range (up to 16 kHz). Frequency response function (FRF) measurements were conducted on an aluminum plate using both the LDV and an accelerometer simultaneously, excited by a scalable automatic modal hammer (SAM). For particular frequency ranges of interest, recommendations for fixation methods are proposed. Recommendations for fixation techniques are proposed for certain frequency ranges. The study’s findings offer practical advice for industrial structure measurement evaluations. An important outcome of this study is how the fixation method influences the experimental results of the modal properties. The research reveals that the fixation, the contact area, the sensor, and the test specimen built a dynamic system that influences the results especially at higher frequencies and should be considered for precise measurements.