The study describes the design and validation of a DMA setup for the characterization of metallic cellular solids in dynamic compressive mode. The goal is to verify the ability of metallic low-density materials to be used as passive dampers for space applications, thanks to their good strength-to-weight ratio and exceptional energy dissipation. Existing literature mostly studied the damping properties of these materials at low frequencies, which are not generally suitable in this field. The setup was designed by means of finite element analyses and verified experimentally. After the structure was completed, the dynamic behaviour of three materials was studied. CuZn foams were unresponsive to changes in excitation frequency and amplitude, but the damping was found to increase for decreasing number of cells per side. Austenitic CuZnAl foams exhibited promising damping properties, thanks to the production of stress-induced martensite at increasing applied loads. Ti-6Al-4V lattice structures were produced by selective laser melting. The study focused not only on their energy dissipation but also on the feasibility of adopting this technology for future projects.
Lo studio descrive la progettazione e la validazione di un setup per analisi meccanica dinamica (DMA), al fine di caratterizzare solidi cellulari in compressione dinamica. L’obiettivo è di verificare l’applicabilità di materiali metallici a bassa densità come smorzatori passivi per applicazione spaziale, grazie al buon rapporto resistenza/peso e l’eccezionale dissipazione di energia. Nella letterature si è studiato principalmente lo smorzamento di questi materiali a basse frequenze, che non sono generalmente appropriate per questo campo di applicazione. Il setup è stato progettato attravero analisi agli elementi finiti e verificato tramite attività sperimentale. Dopo che la struttura è stata completata, si è studiato il comportamento dinamico di tre diversi materiali. Schiume a base CuZn non hanno riportato reazioni diverse al variare della frequenza e ampiezza di eccitazione. Schiume di CuZnAl in fase austenitica hanno mostrato smorzamenti promettenti grazie alla produzione di martensite indotta da sforzo al crescere del carico applicato. Strutture trabecolari in Ti-6Al-4V sono state prodotte tramite selective laser melting. Lo studio si è concentrato non solo sulla loro capacità di disperdere energia, ma anche sulla fattibilità di utilizzare questa tecnologia per progetti futuri.
Development of a DMA setup for cellular solids
SESANA, ALESSIO
2016/2017
Abstract
The study describes the design and validation of a DMA setup for the characterization of metallic cellular solids in dynamic compressive mode. The goal is to verify the ability of metallic low-density materials to be used as passive dampers for space applications, thanks to their good strength-to-weight ratio and exceptional energy dissipation. Existing literature mostly studied the damping properties of these materials at low frequencies, which are not generally suitable in this field. The setup was designed by means of finite element analyses and verified experimentally. After the structure was completed, the dynamic behaviour of three materials was studied. CuZn foams were unresponsive to changes in excitation frequency and amplitude, but the damping was found to increase for decreasing number of cells per side. Austenitic CuZnAl foams exhibited promising damping properties, thanks to the production of stress-induced martensite at increasing applied loads. Ti-6Al-4V lattice structures were produced by selective laser melting. The study focused not only on their energy dissipation but also on the feasibility of adopting this technology for future projects.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/139847