Ultrasonic welding of fiber reinforced thermoplastic composites: Current understanding and challenges

Wang, Yaqiong; Rao, Zhenghua; Liao, Shengming; Wang, Fengjiang

doi:10.1016/j.compositesa.2021.106578

Cited by 50 publications

(21 citation statements)

References 93 publications

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“…Figure 4 b highlights process repeatability for the different input parameters. The lack of process repeatability for certain process parameters is assumed to be the sharp melting temperatures of the CF/PEKK (Wang et al, 2021 ). Therefore, identifying the correct process parameters is crucial to establish a stable process.…”

Section: Methodsmentioning

confidence: 99%

Multi-objective optimisation of ultrasonically welded dissimilar joints through machine learning

et al. 2022

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The use of composite materials is increasing in industry sectors such as renewable energy generation and storage, transport (including automotive, aerospace and agri-machinery) and construction. This is a result of the various advantages of composite materials over their monolithic counterparts, such as high strength-to-weight ratio, corrosion resistance, and superior fatigue performance. However, there is a lack of detailed knowledge in relation to fusion joining techniques for composite materials. In this work, ultrasonic welding is carried out on a carbon fibre/PEKK composite material bonded to carbon fibre/epoxy composite to investigate the influence of weld process parameters on the joint’s lap shear strength (LSS), the process repeatability, and the process induced defects. A 33 parametric study is carried out and a robust machine learning model is developed using a hybrid genetic algorithm–artificial neural network (GA–ANN) trained on the experimental data. Bayesian optimisation is employed to determine the most suitable GA–ANN hyperparameters and the resulting GA–ANN surrogate model is exploited to optimise the welding process, where the process performance metrics are LSS, repeatability and joint visual quality. The prediction for the optimal LSS was subsequently validated through a further set of experiments, which resulted in a prediction error of just 3%.

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Section: Methodsmentioning

confidence: 99%

Multi-objective optimisation of ultrasonically welded dissimilar joints through machine learning

et al. 2022

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“…t d is defined as the time when the workpiece starts to decompose and forms a porous area, while t s is the time when the joint obtains stable weld area. Numerous studies have shown that the weld area of the joints increases rapidly with weld time, and the weld area remains stable at a certain weld time [2,4,8,16]. This particular weld time is defined as t s , and the corresponding joint exhibits the highest strength.…”

Section: Temperature Evolution In Ultrasonic Weldingmentioning

confidence: 99%

“…Joining of thermoplastics in complex structures has become more and more prominent [2]. Ultrasonic welding (UW) is widely used in joining polymers because it is fast, economic, and easy for mass production [3,4]. This technique joins the separated parts by workpiece-to-workpiece friction and viscoelastic dissipation in the polymer (intermolecular friction) [5,6].…”

Section: Introductionmentioning

confidence: 99%

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Double-Pulse Ultrasonic Welding of Carbon-Fiber-Reinforced Polyamide 66 Composite

Zhi

Shu

et al. 2022

Polymers

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Ultrasonic welding of thermoplastics is widely applied in automobile and aerospace industries. Increasing the weld area and avoiding thermal decomposition are contradictory factors in improving strength of ultrasonically welded polymers. In this study, relations among the loss modulus of carbon-fiber-reinforced polyamide 66 composite (CF/PA 66), time for obtaining stable weld area, and time for CF/PA 66 decomposition are investigated systematically. Then, a double-pulse ultrasonic welding process (DPUW) is proposed, and the temperature evolutions, morphologies and structures of fractured surfaces, and tensile and fatigue properties of the DPUWed joints are measured and assessed. Experimental results show the optimal welding parameters for DPUW include a weld time of 2.1 s for the first pulse, a cooling time of 12 s, and a weld time of 1.5 s for the second pulse. The DPUW process enlarged the weld area while avoided decomposition of CF/PA 66 under appropriate welding parameters. Compared to the single-pulse welded joint, the peak load, weld area, and endurance limit of the DPUWed joint increased by about 15%, 23% and 59%, respectively. DPUW also decreases the variance in strengths of the joints.

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“…To reduce fuel consumption and automobile exhaust emissions, automobile manufacturers are actively exploring lightweight and high-performance materials, such as new aluminum/magnesium alloys, and thermoplastic composites, to replace traditional automobile steel [1][2][3]. In particular, carbon-fiber-reinforced nylon-matrix composites are now widely used in mass manufacturing of automobile parts, due to their low cost, relatively high specific strength, and excellent lightweighting effect, which can reduce the weight of automobile parts by more than 40% [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Effect of Preload on the Weld Quality of Ultrasonic Welded Carbon-Fiber-Reinforced Nylon 6 Composite

et al. 2022

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Ultrasonic welding (UW) of polymeric composites is significant in automobile industry; however, maintaining the perfect contact condition between workpieces is a great concern. In this study, effect of preloading and welding pressure on strengths of UWed 2.3-mm-thick short carbon fiber reinforced nylon6 (Cf/PA6) joints with poor contact between workpieces was investigated through stress simulation and energy dissipation at the faying interface. Results showed the application of preloading can increase the strength of normal joint by 18.7% under optimal welding parameters. Gaps between upper and lower workpieces decreased the joint strength significantly, especially for gaps greater than 1.5 mm. Preloading improved the strengths of the joints with gaps remarkably, where the strength of joints with 1.5 mm gap recovered to 95.5% of that the normal joint. When combining the weld nugget evolution, stress-deformation simulation during UW, and ultrasonic vibration transmission analysis, the improvement mechanism of the joint under preloading was mainly because the preloading compacted the contact between workpieces, which favored the energy transmission at faying interface.

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Ultrasonic welding of fiber reinforced thermoplastic composites: Current understanding and challenges

Cited by 50 publications

References 93 publications

Multi-objective optimisation of ultrasonically welded dissimilar joints through machine learning

Multi-objective optimisation of ultrasonically welded dissimilar joints through machine learning

Double-Pulse Ultrasonic Welding of Carbon-Fiber-Reinforced Polyamide 66 Composite

Effect of Preload on the Weld Quality of Ultrasonic Welded Carbon-Fiber-Reinforced Nylon 6 Composite

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