Repairing impacted thermoplastic composites using ultrasonic welding to restore the compressive strength

This research project investigates the potential use of ultrasonic welding as a tool to repair impact damage inside thermoplastic composites to restore the compressive strength. Compared to the already existing method, hot-pressing, ultrasonic welding could offer faster processing times, no need for dedicated tooling, smaller and lighter...

Through the thickness heating in the ultrasonic welding of unidirectional thermoplastic composites

Research and development of thermoplastic composites has been ever increasing owing to the advantages brought by it over conventional materials such as metals and thermoset composites. Higher processing rates, automation, the possibility to recycle, weldability and better mechanical and chemical properties are some of them. Fusion bonding of...

The effect of the adherends' thickness on static ultrasonic welding of thermoplastic composites

Fiber-reinforced polymer composites have gained relevance in the aerospace industry due to their great potential for weight reduction. This, thanks to their outstanding specific properties and ability to be tailored to different applications. Developing efficient composite joining techniques is a challenge that requires great attention as it is...

Improving the quality of continuous ultrasonically welded thermoplastic composite joints by adding a consolidator to the welding setup

Continuous ultrasonic welding is a promising high-speed and energy-efficient joining technique for thermoplastic composite structures. However, in the current state-of-the-art research on the topic numerous deconsolidation voids could be identified at the welding interface, which results in a strength knock-down. The aim of this study is,...

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...

On the sensitivity of the ultrasonic welding process of epoxy- to polyetheretherketone (PEEK)-based composites to the welding force and amplitude of vibrations

This paper addresses the sensitivity of the ultrasonic welding process for joining dissimilar composites to variations in either the welding force or amplitude of vibrations. For that, carbon fibre (CF)/epoxy specimens were welded to CF/polyetheretherketone (PEEK) specimens, through a polyetheretherimide (PEI) coupling layer co-cured with the...

Effect of consolidation parameters on (de)consolidation in ultrasonic welding of thermoplastic composites

Thermoplastic composites are gaining prominence in the aerospace industry owing to their higher damage tolerance, cost-efficient means of manufacturing, and the possibility to be recycled. One of the major benefits of thermoplastics compared to thermosets is their ability to be welded, and one of the most promising welding techniques for...

Investigating the Degree of Crystallinity in Ultrasonically Welded Thermoplastic Composite Joints

Ultrasonic Welding is a fusion bonding method that can create high-strength thermoplastic composite joints at very fast speeds. This makes it a very promising method for use in the aerospace industry, though further research is required to mature it. One topic of interest is how the crystallinity of the polymer matrix in the joint is affected by...

Ultrasonic welding of CF/epoxy to CF/PEEK composites: Effect of the energy director material on the welding process

With its short heating times, ultrasonic welding is a highly promising technique for joining thermoplastic (TPC) to thermoset (TSC) composites, to prevent thermal degradation of the thermoset adherend. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the TSC “weldable”. For welding CF/PEEK to a TSC adherend,...

Diagnostic of manufacturing defects in ultrasonically welded thermoplastic composite joints using ultrasonic guided waves

This article presents research about the propagation of ultrasonic guided waves in ultrasonically welded thermoplastic composite joints. The goal of the study was to understand the effect of weld manufacturing defects on guided wave transmission across the joint. Triangular energy-directors integrated into the lower composite adherends...

Investigating the use of Fused Deposition Modeling as Energy Director application method for Ultrasonic Welding of Thermoplastic Composites

The joining of high performance Thermoplastic Composite (TPC) structures by Ultrasonic Welding (USW) is considered a promising alternative for mechanical joining or adhesive bonding methods. The process is fast, clean, and highly automated. In the USW process, an intermediate, unreinforced polymer layer is required at the weld interface to...

Experimental assessment of the influence of welding process parameters on Lamb wave transmission across ultrasonically welded thermoplastic composite joints

One of the advantages of thermoplastic composites relative to their thermoset counterparts is the possibility of assembling components through welding. Ultrasonic welding in particular is very promising for industrialization. However, uncertainty in the fatigue and fracture behaviour of composites is still an obstacle to the full utilisation...

Ultrasonic Plastic Welding of Dissimilar Materials: Experimental investigation of metal/carbon fiber reinforced thermoplastic joints

Due to EU regulations on fuel consumption, reducing the weight of vehicles has become one of the most important goals of car manufacturers in Europe. Among them, Toyota Motor Europe is one of the worldwide leaders in the research for a sustainable future. Materials like fiber-reinforced plastics and aluminum play a significant role in the...