PSI - Issue 75

Sébastien Boudevin et al. / Procedia Structural Integrity 75 (2025) 72–84 Author name / Structural Integrity Procedia (2025)

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If we focus on the load case while the device is operating, mission profile can be described within a flowchart with events or life phases processed in series, including non-stationary transient signals for startup and shutdown of the compressor as well as stationary sine on random signals induced by magnetic induction mechanism between stator and rotor coils (see Fig. 4).

Fig. 4. Heat pump profile mission in operating phase

Previously, acceleration levels of the heat pump were characterized and prepared in the test database, with storing corresponding FDS and ERS adding their context as life situation (see Fig. 5 and 6). Next, two validation test profiles defined by APSD random spectrum were synthesized based on reference FDSs, for both startup / shutdown phases and operating phases. Only the APSD random profile related to long-term operating phase was accelerated, in compliance with an acceptance criterion between the synthesized ERS and the reference envelope SRS.

Fig. 5 and 6. FDS and SRS synthesis based on n-SDOF response from heat pump acceleration measurements

Finaly, from a reliability point of view and for a given failure rate, a safety APSD validation profile was defined by multiplying the synthesized APSD by a correction factor k(f) ^(2/b) , the b parameter being the Basquin exponent of the SN curve (see Fig. 7).