scholarly journals A study on amplitude transmission in ultrasonic welding of thermoplastic composites

2018 ◽  
Vol 113 ◽  
pp. 339-349 ◽  
Author(s):  
Genevieve Palardy ◽  
Huajie Shi ◽  
Arthur Levy ◽  
Steven Le Corre ◽  
Irene Fernandez Villegas
Keyword(s):  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Amplitude Transmission

scholarly journals Static ultrasonic welding of carbon fibre unidirectional thermoplastic materials and the influence of heat generation and heat transfer

2021 ◽  
pp. 002199832097681
Author(s):  
F Köhler ◽  
IF Villegas ◽  
C Dransfeld ◽  
A Herrmann
Keyword(s):  
Cross Sections ◽  
Weld Line ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Squeeze Flow ◽  
Anisotropic Flow ◽  
Lap Shear ◽  
Anisotropic Thermal Conductivity ◽  
Edge Defects

Ultrasonic welding is a promising technology to join fibre-reinforced thermoplastic composites. While current studies are mostly limited to fabric materials the applicability to unidirectional materials, as found in aerospace structures, would offer opportunities for joining primary aircraft structures. However, due to the highly anisotropic flow of a molten unidirectional ply undesired squeeze flow phenomena can occur at the edges of the weld overlap. This paper investigates how the fibre orientation in the plies adjacent to the weld line influences the welding process and the appearance of edge defects. Ultrasonic welding experiments with different layups and energy director configurations were carried out while monitoring temperatures at different locations inside and outside the weld overlap. The joints were characterized by single lap shear tests, analysis of corresponding fracture surfaces and microscopic cross-sections. Results showed that the anisotropic flow and the anisotropic thermal conductivity of the plies adjacent to the weld line have a distinct effect on the appearance and location of edge defects. By using energy directors that cover only part of the weld overlap area a new approach was developed to mitigate edge defects caused by the highly directional properties of the unidirectional plies.

The Effects of Energy Director Shape on Temperature Field during Ultrasonic Welding of Thermoplastic Composites

2007 ◽  
Vol 353-358 ◽  
pp. 2007-2010 ◽  
Author(s):  
Jiu Chun Yan ◽  
Xiao Lin Wang ◽  
Rui Qi Li ◽  
Hui Bin Xu ◽  
Shi Qin Yang
Keyword(s):  
Welding Process ◽  
Element Model ◽  
Ultrasonic Welding ◽  
The Body ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Glass Transformation ◽  
Different Shapes ◽  
Energy Director ◽  
Different Order

The ultrasonic welding process of thermoplastic composite with different shapes of energy director (ED) was simulated using finite element model. The results show that the highest temperature zone locates at the tip for the semicircular and triangular ones, and locates at the middle height for the trapezoid one. But it does not locate at the body of ED for the rectangular one. Energy director with different shapes lead to the temperature rising rate at different order of amplitude. The welding amplitude has same influence on the four shapes of ED. The temperature distributing profiles of semicircular, triangular and trapezoid ED keep constant from the initial welding time to that when the highest temperature on joints arrives the temperature of glass transformation (Tg), but the profile for rectangular ED changes greatly.

scholarly journals Continuous ultrasonic welding of thermoplastic composites: Enhancing the weld uniformity by changing the energy director

2019 ◽  
Vol 54 (15) ◽  
pp. 2023-2035 ◽  
Author(s):  
Bram Jongbloed ◽  
Julie Teuwen ◽  
Genevieve Palardy ◽  
Irene Fernandez Villegas ◽  
Rinze Benedictus
Keyword(s):  
Thin Film ◽  
Heat Generation ◽  
High Speed ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Weld Strength ◽  
Good Contact ◽  
Energy Director ◽  
Welded Seam

Continuous ultrasonic welding is a high-speed joining method for thermoplastic composites. Currently, a thin film energy director is used to focus the heat generation at the interface. However, areas of intact energy director remain in the welded seam, which significantly lowers the weld strength, and result in a non-uniformly welded seam. To improve the weld uniformity of continuous ultrasonically welded joints, we changed to a more compliant energy director. A woven polymer mesh energy director was found to give a significant improvement in weld quality. The mesh was flattened in between the composite adherends during the welding process. This flattening promoted a good contact between the energy director and the adherends, fully wetting the adherend surfaces, resulting in a more uniformly welded seam without areas of intact energy director.

scholarly journals Advances in Ultrasonic Welding of Thermoplastic Composites: A Review

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1284 ◽  
Author(s):  
Somen K. Bhudolia ◽  
Goram Gohel ◽  
Kah Fai Leong ◽  
Aminul Islam
Keyword(s):  
Composite Structures ◽  
Dissimilar Materials ◽  
Processing Parameters ◽  
Ultrasonic Welding ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Pressure Amplitude ◽  
Advantages And Disadvantages ◽  
Cost Efficient ◽  
Weld Time

The ultrasonic welding (UW) technique is an ultra-fast joining process, and it is used to join thermoplastic composite structures, and provides an excellent bonding strength. It is more cost-efficient as opposed to the conventional adhesive, mechanical and other joining methods. This review paper presents the detailed progress made by the scientific and research community to date in the direction of the UW of thermoplastic composites. The focus of this paper is to review the recent development of the ultrasonic welding technique for thermoplastic composites to thermoplastic composites, and to dissimilar materials. Different ultrasonic welding modes and their processing parameters, namely, weld time, weld pressure, amplitude, type of energy directors (EDs) affecting the welding quality and the advantages and disadvantages of UW over other bonding techniques, are summarized. The current state of the ultrasonic welding of thermoplastic composites and their future perspectives are also deliberated.

scholarly journals Enhanced Performance of Ultrasonic Welding of Short Carbon Fiber Polymer Composites Through Control of Morphological Parameters

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Tae Hwa Lee ◽  
Hua-Tzu Fan ◽  
Yang Li ◽  
Daniel Shriver ◽  
Jorge Arinez ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Nylon 6 ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Degree Of Crystallinity ◽  
Weld Strength ◽  
Morphological Parameters ◽  
Scanning Calorimetry ◽  
Short Carbon Fiber ◽  
Short Carbon

Abstract Ultrasonic welding (USW) is one of the joining technologies that can be applied to short carbon fiber thermoplastic composites. In this study, the USW of Nylon 6 reinforced by short carbon fibers created using injection molding is used to investigate the USW process without energy directors. In addition to process parameters and performance parameters, a new category of parameters is introduced to characterize the behavior of base materials to control USW without energy directors. These parameters, named morphological parameters, are the degree of crystallinity (DoC) and the ratio of the crystalline phases of Nylon 6 (α/γ ratio). One method of controlling the morphological parameters is annealing. A design of experiments is carried out using 5 replicates and 7 annealing temperatures above the glass transition temperature (Tg) and below the melting temperature (Tm) of Nylon 6 to investigate the influence of annealing on the morphological parameters. The DoC and α/γ ratio are measured for each replicate by utilizing differential scanning calorimetry and X-ray diffraction. The results show that the DoC becomes uniform and the α/γ ratio increases after annealing. Consequently, the variation in weld strength decreases and the average weld strength increases by controlling the morphological parameters through annealing.

Sign in / Sign up

Export Citation Format

Share Document