Marco Pacchione

Mechanical behaviour of AA 2024 friction stir overlap welds

Purpose – To investigate the effect of different welding configurations on the mechanical properties of friction stir welding (FSW) overlap joints. The application of FSW in an overlap configuration could be an attractive replacement to the riveting process for assembly of fuselage primary structures due to the similarity in tolerance management. However, the mechanical properties of welded overlap joints are often inferior to the respective riveted lap‐joint properties.Design/methodology/approach – In order to quantify the static and fatigue strength of FSW overlap joints, numerical and experimental investigation on overlap welds were performed in the current work. Several single shear overlap joints welding configurations were investigated, including single and multiple pass friction stir welds. The static and fatigue behaviour of these joints was assessed through tensile and fatigue tests.Findings – Static and fatigue behaviour were found to strongly depend on the welding process parameters and configu...

Hybrid Metal Laminates for Low Weight Fuselage Structures

Metal Laminates (MLs), combined with selective reinforcements and bonded design principles, is a hybrid structural concept suitable for use in primary fuselage structures. Following a screening of the static, fatigue and damage tolerance performances of thin MLs coupons an investigation, focused on identification of fuselage areas best suited for ML application has been performed. After a weight optimization analysis large panel tests have been defined and tested to investigate the two main structural design requirements: the post-buckling shear-compression response, and the F&DT behavior including large damage capability, of thin ML shells.

Experimental investigation of reinforced bonded joints for composite laminates

An experimental study has been carried out to investigate the behaviour of co-bonded carbon fibre reinforced plastics joints with a novel design incorporating a through the thickness local reinforcement. Different specimens were manufactured to investigate static and fatigue behaviour, as well as delamination size after impact and damage tolerance characteristics. The mechanical performances of the specimens with local reinforcement, consisting of the insertion of spiked thin metal sheets between co-bonded laminates, were compared with those ones obtained from specimens with purely co-bonded joints. This novel design demonstrated by tests that damage progression under cycling load results significantly delayed by the reinforcements. A significant number of experimental results were obtained that can be used to define preliminary design guidelines.