Current research aims at investigating the fatigue strength of ultrasonically welded composite joints with novel liquid acrylic thermoplastic Elium®. Fatigue response of the welded joints with integrated Energy Director (ED) and flat Elium® film was investigated and the baseline comparison was carried out with control adhesives. The results showed 10–12% higher fatigue life at 105 and 106 fatigue cycle as compared to the adhesively bonded joints. Fractographic investigation of fractured welded joints showed
