Development of a comprehensive mathematical model for simulating the effects of misalignments in vibration measurements using scanning LDV measurement systems

Scanning mirrors are very important contributors of a SLDV system. These mirrors are often installed inside the laser head thereby the optical access of the targeted structure must be always available during testing. However, some applications could benefit of having a laser head decoupled from the scanner so to positioning the twos in an optimum way, although this can introduce possible sources of misalignments. This paper presents the development of a mathematical model for simulating the effects of misalignment in vibration measurements using scanning LDV measurement systems. The misalignments between the laser source and the scanning unit, and between the latter and the target structure is a source of uncertainty, producing pseudo-vibrations and causing relative motion of the laser beam on the target surface. Using such a mathematical model, the effects of each parameter of misalignment can be simulated and studied. This work aims to presents simulations of all sources of misalignments when the scanners are decoupled from the laser head.