Modern structures are designed to withstand in-service loads over a broad frequency spectrum. Nonetheless, mechanical properties in numerical codes are assumed to be frequency-independent to simplify calculations or due to a lack of experimental data, and this approach could lead to overdesign or failures. This study aims to quantify the frequency effects in the fatigue applications of a bi-material adhesive joint through analytical, numerical, and experimental procedures. Analytical and finite element models allowed the specimen design, whereas the frequency effects were investigated through a conventional servo-hydraulic apparatus at 5, 25, and 50 Hz and with an ultrasonic fatigue testing machine at 20 kHz. Experimentally, the fatigue life increases with the applied test frequency. Run-out stress data at 109 cycles follow the same trend: at 25 Hz and 50 Hz, the run-out data were found at 10 MPa, increasing to 15 MPa at 20 kHz. The P-S-N curves showed that frequency effects have a minor impact on the experimental variability and that standard deviation values lie in the range of 0.3038-0.7691 between 5 Hz and 20 kHz. Finally, the trend of fatigue strengths at 2 center dot 106 cycles with the applied loading frequency for selected probability levels was estimated.

Effect of Loading Frequency on the Fatigue Response of Adhesive Joints up to the VHCF Range / Pederbelli, D; Goglio, L; Paolino, D; Rossetto, M; Tridello, A. - In: APPLIED SCIENCES. - ISSN 2076-3417. - 13:23(2023). [10.3390/app132312967]

Effect of Loading Frequency on the Fatigue Response of Adhesive Joints up to the VHCF Range

Pederbelli, D;Goglio, L;Paolino, D;Rossetto, M;Tridello, A
2023

Abstract

Modern structures are designed to withstand in-service loads over a broad frequency spectrum. Nonetheless, mechanical properties in numerical codes are assumed to be frequency-independent to simplify calculations or due to a lack of experimental data, and this approach could lead to overdesign or failures. This study aims to quantify the frequency effects in the fatigue applications of a bi-material adhesive joint through analytical, numerical, and experimental procedures. Analytical and finite element models allowed the specimen design, whereas the frequency effects were investigated through a conventional servo-hydraulic apparatus at 5, 25, and 50 Hz and with an ultrasonic fatigue testing machine at 20 kHz. Experimentally, the fatigue life increases with the applied test frequency. Run-out stress data at 109 cycles follow the same trend: at 25 Hz and 50 Hz, the run-out data were found at 10 MPa, increasing to 15 MPa at 20 kHz. The P-S-N curves showed that frequency effects have a minor impact on the experimental variability and that standard deviation values lie in the range of 0.3038-0.7691 between 5 Hz and 20 kHz. Finally, the trend of fatigue strengths at 2 center dot 106 cycles with the applied loading frequency for selected probability levels was estimated.
2023
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2984781