Continuous, Free‐Formable Sandwich Design with 3D Fiber Reinforced Core for Increased Lightweight Level of Applications in Large‐Scale Production

Schäfer, Kay; Stiller, Jonas; Tröltzsch, Jürgen; Nestler, Daisy; Kroll, Lothar

doi:10.1002/adem.201800477

Cited by 3 publications

(4 citation statements)

References 29 publications

(31 reference statements)

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“…However, high costs and low production tempo of the traditional composite molding process limits its development. The thermal expansion molding process (TEMP) is a neotype molding technology for sandwich composites 3–5 . The expandable foam serves as the lightweight core and internal expansion source, reducing costs and improving the production efficiency 6 .…”

Section: Introductionmentioning

confidence: 99%

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Preparation and properties of expandable epoxy foam prepreg for sandwich composites prepared via thermal expansion molding process

Wei

Zhao

et al. 2022

J of Applied Polymer Sci

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Thermal expansion molding process (TEMP) is a new technology for integrated molding sandwich composites. However, the development of high-performance expandable foam prepreg limits the scale applications of this technology. In this study, epoxy foam prepreg (M-1) with expandable function was used to prepare foams with different expansion ratios via restricted foaming. Three suitable expansion ratios were determined to prepare foam sandwich composites by analyzing the density, bubble sizes, compressive strength, and expansion pressures of expandable foam. The maximum expansion pressure produced by four, six, and eight times of foam expansion were 251, 160, and 115 kPa, respectively. Tensile test and digital imaging computer technology confirmed that with the increase of foam expansion ratio, the strength decreased, but the plastic deformation ability increased. Failure modes such as foam matrix fracture, glass fiber mat fracture, and mutual-slipping between the foam matrix and glass fiber mat occur during the stretching process. Finally, the PMI/M-1 foam hybrid sandwich composites with three structures were prepared via the TEMP technology, which verified the feasibility of this technology in forming sandwich composites.expandable foam, expansion pressure, sandwich composites, TEMP technology, tensile properties | INTRODUCTIONFoam sandwich composites are widely applied in automobiles, aerospace, sports, and other fields owing to their light weight and high strength. 1,2 However, high costs and low production tempo of the traditional composite molding

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Section: Introductionmentioning

confidence: 99%

“…The thermal expansion molding process (TEMP) is a neotype molding technology for sandwich composites. [3][4][5] The expandable foam serves as the lightweight core and internal expansion source, reducing costs and improving the production efficiency. 6 Therefore, lightweight expandable foam is vital for the TEMP technology.…”

mentioning

confidence: 99%

Preparation and properties of expandable epoxy foam prepreg for sandwich composites prepared via thermal expansion molding process

Wei

Zhao

et al. 2022

J of Applied Polymer Sci

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“…The mass reduction of structure elements, defined as lightweight parts, while maintaining or improving its mechanical properties is one of the observed trends in product design. In consequence, it is possible to increase the participation of lightweight polymer elements in the construction of cars to reduce their weight, thus reducing fuel consumption and carbon footprint [ 8 , 9 , 10 ]. Therefore, it can be concluded that Microcellular Injection Molding (MIM) technologies support those activities aimed at producing lightweight products with cells structure for engineering applications [ 3 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

High-Performance of a Thick-Walled Polyamide Composite Produced by Microcellular Injection Molding

2021

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Lightweight moldings obtained by microcellular injection molding (MIM) are of great significance for saving materials and reducing energy consumption. For thick-walled parts, the standard injection molding process brings some defects, including a sink mark, warpage, and high shrinkage. Polyamide 66 (PA66)/glass fiber (GF) thick-walled moldings were prepared by MuCell® technology. The influences of moldings thickness (6 and 8.4 mm) and applied nitrogen pressure (16 and 20 MPa) on the morphology and mechanical properties were studied. Finally, the microcellular structure with a small cell diameter of about 30 μm was confirmed. Despite a significant time reduction of the holding phase (to 0.3 s), high-performance PA66 GF30 foamed moldings without sink marks and warpage were obtained. The excellent strength properties and favorable impact resistance while reducing the weight of thick-walled moldings were achieved. The main reason for the good results of polyamide composite was the orientation of the fibers in the flow direction and the large number of small nitrogen cells in the core and transition zone. The structure gradient was analysed and confirmed with scanning electron microscopy (SEM) images, X-ray micro computed tomography (micro CT) and finite element method (FEM) simulation.

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“…This paper deals with the addition of such core composites with endless fibre-reinforced thermoplastic facings to sandwiches. The development of efficient processes for the production of such complex structures for medium and large series is challenging [14]. The number of process steps has to be minimised.…”

Section: Introduction and State Of The Artmentioning

confidence: 99%

Lightweight Potential of 3D Endless Fiber Reinforcement of Polyurethane Foam Cores with Spacer Fabrics in Hybrid Sandwich Structures with Fiber Reinforced Thermoplastic Facings

Schäfer

Nestler

Jahn

et al. 2019

KEM

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Sandwich structures consisting of fibre-reinforced plastic (FRP) facings and core are ideally suited as substitution materials for reducing component masses. The endless fibre reinforcement has the greatest performance potential. Both thermoset and thermoplastics are already being processed into endless fibre-reinforced sandwich facings according to the state of the art. The 3D endless fibre reinforcement of cores is a current research topic. This paper describes the development of a hybrid sandwich consisting of thermoplastic composite facings and an innovative core composite. This is made of polyurethane (PUR) rigid or flexible foam, which is reinforced with spacer fabric. The sandwich manufacturing in Reaction Injection Moulding (RIM) includes the original forming of the core and the simultaneous bonding of the facings. This efficient process offers the potential for the production of such complex structures in medium or large series. The sandwich structures and their individual components were characterised in the standardised compression and bending test. The lightweight potential of spacer fabric reinforcement is demonstrated by comparing the specific mechanical properties of sandwich structures with and without core reinforcement. In comparison to reinforced and unreinforced foams, the effect of sandwich design is also shown.

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Continuous, Free‐Formable Sandwich Design with 3D Fiber Reinforced Core for Increased Lightweight Level of Applications in Large‐Scale Production

Cited by 3 publications

References 29 publications

Preparation and properties of expandable epoxy foam prepreg for sandwich composites prepared via thermal expansion molding process

Preparation and properties of expandable epoxy foam prepreg for sandwich composites prepared via thermal expansion molding process

High-Performance of a Thick-Walled Polyamide Composite Produced by Microcellular Injection Molding

Lightweight Potential of 3D Endless Fiber Reinforcement of Polyurethane Foam Cores with Spacer Fabrics in Hybrid Sandwich Structures with Fiber Reinforced Thermoplastic Facings

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