About airborne fatigue life predictions by means of full-field receptances. Part B: estimating the failure distribution with spectral methods.

Airborne pressure fields, with their variable spectral content in the acoustic and frequency domains, can become a threatening dynamic distributed loading for many surfaces in industrial applications, thus leading to airborne fatigue. Part A of this research path retrieves the structural force spectrum, as induced by the modelled airborne pressure fields on the real thin plate tested, which becomes the dynamic excitation for the structural dynamics in this Part B, leading to cumulative damage and fatigue life considerations. Reliable and advanced full-field receptance testing – as substitution of any other numerical model about the mounted realisation of the specific components – can nowadays be made by means of optical measurements. The quality achieved in the receptance maps helps in numerically derive the strain FRFs on the sensed surfaces. With proper constitutive models, the experiment-based mapping of the equivalent stresses can be achieved. Fatigue spectral methods turn this knowledge into component’s life distributions with the unmatched mapping ability of contactless full-field techniques. Full-field optical receptance maps turn to be pivotal in accurately representing the structural dynamics when retrieving the induced force by airborne pressure fields in Part A, and when mapping the effective solicitations for the airborne fatigue life predictions of Part B.