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

2022 ◽  
pp. 106808
Author(s):  
Bram Jongbloed ◽  
Rahul Vinod ◽  
Julie Teuwen ◽  
Rinze Benedictus ◽  
Irene Fernandez Villegas
Keyword(s):  
Thermoplastic Composite ◽  
Composite Joints

Conical Thermoplastic Composite Anisogrid Lattice Structure by Innovative Out-of-Autoclave Molding Process

2021 ◽  
Author(s):  
Fabrizio Quadrini ◽  
Daniele Santoro ◽  
Leandro Iorio ◽  
Loredana Santo
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Glass Fibers ◽  
Density Measurement ◽  
Thermoplastic Composite ◽  
Molding Process ◽  
Conical Structure ◽  
Out Of Autoclave ◽  
Composite Lattice

Abstract A new manufacturing process for thermoplastic (TP) composite parts has been used to produce conical anisogrid composite lattice structure (ACLS). An out-of-autoclave (OOA) process has been prototyped by using the compaction exerted by a heat-shrink tube after its exposition to heat in oven. Narrow thermoplastic prepreg tapes have been wounded on a metallic conical patterned mold at room temperature; then, the conical structure has been inserted in the heat-shrink tube and heated. TP unidirectional prepreg tapes have been used with polypropylene matrix and glass fibers. After molding, the TP ACLS has been tested under axial and transverse compression. Conical adapters were used in the transverse loading condition to allow uniform application of the load. Density measurement has been also performed to assess the quality of the OOA process. Results of this study show that TP ACLS with complex shape may be produced with OOA solutions without affecting mechanical performance. In fact, porosity levels of the consolidate ACLS are comparable with the initial prepreg despite of the absence of vacuum during molding. Moreover, high compressive stiffness was measured along both directions without observing damages, buckling or cracks in multiple tests. In the future, this kind of technology could be used for larger ACLSs by substituting the heat-shrink tube with a narrow tape to be wound as well after lamination.

Scaling issues in resistance-welded thermoplastic composite joints

1997 ◽  
Vol 16 (4) ◽  
pp. 279-295 ◽  
Author(s):  
Steven H. McKnight ◽  
Scott T. Holmes ◽  
John W. Gillespie ◽  
Cynthia L. T. Lambing ◽  
James M. Marinelli
Keyword(s):  
Thermoplastic Composite ◽  
Composite Joints

Effect of forming process on mechanical and interfacial properties for thermoplastic composite I-stiffened structures

2021 ◽  
pp. 095400832110515
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Bonding Strength ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Forming Process ◽  
Molding Process ◽  
Influencing Mechanism ◽  
Stiffened Structures ◽  
The Common ◽  
Polymer Aging

The forming process is the core factor to control the quality of thermoplastic composite components. In this paper, the common I-stiffened structures in the aerospace field were taken as the research object, and the forming process scheme was designed. Based on the prefabrication of C-shaped parts, the I-stiffened structures were prepared by the compression molding process. The influence law of molding temperature on the quality of the prefabricated C-shaped parts was explored. The time dependence of the PEEK melt viscosity was tested to provide the basis for the optimization of forming process parameters of I-stiffened structures. The influencing mechanism of thermoplastic composites repeatedly forming to the bonding strength of remelting interface was studied. The results show that repeated forming would lead to polymer aging and result in low bonding strength at the remelting interface of the I-stiffened structures. Optimizing the forming process could effectively reduce the aging of materials and improve the bonding strength of the remelting interface and overall mechanical properties of components. The research provides technical guidance for the manufacturing of complex thermoplastic composite components, especially the influence mechanism of the forming process on the bonding strength of remelting interface.

On the Manufacturing Defects of Thermoplastic Carbon/Epoxy Composites Manufactured by Automated Tape Placement

2020 ◽  
Author(s):  
Tamer A. Sebaey ◽  
Noel O’Dowd
Keyword(s):  
Solidification Process ◽  
The Other ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Circular Statistics ◽  
Engineering Practice ◽  
Manufacturing Defects ◽  
Thermoset Composites ◽  
Manufacturing Techniques

Abstract Thermoplastic composites are highly recommended for structural application, not only for their superior characteristics derived from the fiber and matrix materials but also for their recycling possibilities, which is a major issue in the today’s engineering practice. The manufacturing techniques for thermoplastics are different from those for the well-established thermoset composites. This paper addresses the quality of the thermoplastic composites by assessing the distribution of the fiber, the void contents and the waviness of the fibers, compared to the thermoset composites. IM7/PEEK and AS4/PA12 are the two thermoplastic composite systems used for this study, whereas, IM7/8552 is the thermoset composite used as reference. The specimens were examined using optical microscopy and computed tomography (CT) and the results were statistically treated using circular statistics. Compared to the IM7/8552 composite, the analysis reveals that the IM7/PEEK and AS4/PA12 composites, manufactured by ATP result in a higher volume of voids. On the other hand, ATP processing improves the alignment of the fibers, as the solidification process occurs while the fibers are in tension. The microscopy studies also show that the ATP manufactured composites have an area in between the different layers of tape with a low number of fibers, compared to the other areas.

scholarly journals Simulation of the Thermoforming Process of Glass Fiber Reinforced Polymeric Components: Investigation of the Combined Effect of the Crosshead Speed and Material Temperature

2021 ◽  
Author(s):  
Antonios Stamopoulos ◽  
Antoniomaria Di Ilio ◽  
Luca Glauco Di Genova
Keyword(s):  
Elevated Temperatures ◽  
Thickness Distribution ◽  
Mechanical Tests ◽  
Point Of View ◽  
Material Behavior ◽  
Thermoplastic Composite ◽  
Residual Stress Field ◽  
Crosshead Speed ◽  
Thermoforming Process

Abstract Thermoplastic based composite materials are increasingly gaining the interest of many engineering sectors, among them the automotive. Their unique features, resulted by the thermoplastic matrix characteristics, such as their recyclability and their formability have given new perspectives in their use. Among the most promising fabrication methods of thermoplastic composite components is the thermoforming process, the press forming of a heated semi-finalized composite plate. This method, although requires a quite simple working station and can be implemented in mass production, demonstrates a series of disadvantages on the quality of the product. Among them, the variation of the thickness, formation of wrinkles and overall undesired deformations are considered as defects that decrease the quality not only from the esthetical but also from the structural point of view. In the present work, a numerical analysis of the thermoforming process is conducted when applied to a box-shaped geometry. As an input for the material behavior during the process, mechanical tests are conducted at elevated temperatures. The flat and curved critical zones of the component are identified and an analysis of the effect of the temperature and the crosshead speed of the molds on the thickness distribution are examined as well as the overall residual stress field. The results indicate a strong dependency of the quality of the product by these parameters of the process.

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