Automated Sequential Ultrasonic Welding on a full-scale Thermoplastic Composite Fuselage demonstrator

Multi-spot sequential ultrasonic welding is a promising joining technique for thermoplastic composites in an overlap configuration. In the framework of the EU Clean Sky 2 Multi-functional fuselage demonstrator (MFFD) and the lower shell SmarT multifUNctioNal and INteGrated TP fuselage (STUNNING) projects, a robot-based sequential ultrasonic spot...

Disassembly of fusion bonded thermoplastic composite joints aided by induction heating: Effects of induction heating on disassembly force and damage patterns

Disassembly of fusion bonded joints aided by induction heating was investigated. Single-lap shear experiments were performed while heating the joint with an induction coil to research the effect on force required and damage inflicted during disassembly. Co-consolidated CF/PEEK samples with and without a metal mesh susceptor and ultrasonically...

Fatigue Behavior of Multi-Spot Welded Joints in Thermoplastic Composites: Effects of Spot Arrangement in a Four-Spot Joint

Welding is a joining method for thermoplastic composites (TPCs) that offers multiple advantages over the more traditional methods of mechanical fastening and adhesive bonding. A particularly promising welding technique is ultrasonic welding, which features very short process times as a result of the high heating rates that can be achieved. This...

Thermal effects on the performance of ultrasonically welded CF/PPS joints and its correlation to the degree of crystallinity at the weldline

The effect of temperature on the lap shear strength (LSS) and failure mechanisms of ultrasonically welded carbon fibre reinforced polyphenylene sulphide (CF/PPS) joints was investigated, correlating the weld performance to the crystallinity degree of PPS at the weldline. The single-lap shear tests were carried out at temperatures ranging from...

Thermal effects on thermoplastic composites welded joints: A physical and mechanical characterisation

The use of high performance thermoplastic composites (TPCs) in the aviation industry has increased over the last years. TPCs have significant advantages such as superior damage tolerance, excellent chemical resistance and the ability to be welded. To date, mechanical fastening, primarily, and adhesive bonding are the two traditional joining...

Improving weld uniformity in continuous ultrasonic welding of thermoplastic composites

Continuous ultrasonic welding (CUW) is an innovative high-speed joining method for thermoplastic composites. Currently, thin flat energy directors (EDs) are used to focus the heat generation at the weld line. The resulting fracture surfaces exhibit large areas of intact ED, resulting in a non-uniform weld, and significantly lowering the strength...

Ultrasonic welding of CF/PPS composites with integrated triangular energy directors: melting, flow and weld strength development

This paper presents a fully experimental study on melting, flow and weld strength development during ultrasonic welding of CF/PPS composites with integrated triangular energy directors. The main goal of this research was assessing whether the heating time to achieve maximum weld strength could be significantly reduced as compared to...

On the effect of flat energy directors thickness on heat generation during ultrasonic welding of thermoplastic composites

This paper presents a detailed experimental assessment of the effect of the thickness of flat energy directors (ED) on heat generation at the interface during ultrasonic welding. Power and displacement data showed clear differences caused by the change of thickness, related to heat concentration at the weld line during the process. The extent...