Mechanical joining without auxiliary element by cold formed pins for multi-material-systems

Kraus, Martin; Frey, Philipp; Kleffel, Tobias; Drummer, Dietmar; Merklein, Marion

doi:10.1063/1.5112570

Cited by 18 publications

(29 citation statements)

References 6 publications

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“…In the Y/Z plane, the most notable phenomenon is a significant fiber displacement in the direction of the press-in-operation (Z-direction) accompanied by fiber compression between the tip of the inserted pin and the surface of the CFRT sample as it was already discovered in [20]. This fiber displacement can be observed for all investigated pin-geometries with no fundamental differences between different diameters and tip angles.…”

Section: Fiber Orientationsupporting

confidence: 56%

“…In comparison to Kraus et al, where the pins have an average height of 1.47 mm the pins in this study are 0.33 mm longer. [20]. The examined diameters d are 1.00 mm, 1.25 mm and 1.50 mm and the tip angles α are 180° (flat), 120°, 90° and 60°.…”

Section: Definition Of Pin-geometrymentioning

confidence: 97%

“…In Plettke et al pins with a diameter of 1.0 mm [19] and in Kraus et al pins with a diameter of 1.32 mm [20] have been used to join metal and CFRT. In both studies loadable joints were created.…”

Section: Definition Of Pin-geometrymentioning

confidence: 99%

“…For CFRT-metal hybrid parts, the direct pressing of metallic pins into a locally heated CFRT part, to form a force-fitting as well as interlocking connection, is shown in Plettke et al on the example of additively manufactured metallic pins [19] as well as in Kraus et al on the example of cold formed metallic pins [20]. In the cited studies, the general feasibility to create a loadable metal-CFRT joint with this technique is demonstrated.…”

Section: Introductionmentioning

confidence: 98%

“…In both studies, no systematical investigation of the influence of different pin geometries on the resulting fiber orientation is conducted. However, Kraus et al showed the resulting fiber orientation on the example of a cylindrical pin with a diameter of 1.32 mm [20].…”

Section: Introductionmentioning

confidence: 99%

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Fiber Orientation Mechanism of Continuous Fiber Reinforced Thermoplastics Hybrid Parts Joined with Metallic Pins

et al. 2021

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Continuous Fiber Reinforced Thermoplastic (CFRT) hybrid parts offer interesting possibilities for lightweight application, which can exceed the capabilities of mono material metal or CFRT parts. In this case, the joining technology oftentimes is the limiting factor. This study investigates a joining operation with metal pin structures which are additively manufactured via powder bed fusion featuring different diameters and tip geometries, which are inserted into the locally infrared heated CFRT part. The resulting fiber rearrangement is assessed using transmitted light microscopy, confocal laser scanning microscopy as well as micro-computer-tomography. It could be shown that for all assessed pin variants a similar distinct fiber displacement can be seen and that the pin diameter has a significant effect on the resulting fiber orientation with smaller pin diameters being advantageous because of gentle fiber displacement and reduced undulation. The tip geometry has only minor effect on the fiber orientation. Especially in the X/Y plane no systematic influence of the tip geometry on the fiber displacement could be observed. Based on the gained insights a three-stage model of the fiber orientation processes is proposed.

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Section: Fiber Orientationsupporting

confidence: 56%

Section: Definition Of Pin-geometrymentioning

confidence: 97%

Section: Definition Of Pin-geometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Fiber Orientation Mechanism of Continuous Fiber Reinforced Thermoplastics Hybrid Parts Joined with Metallic Pins

et al. 2021

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Influence of the Textile Reinforcement on the Joint Formation of Pin-Joined Composite/Metal Parts

Popp,

Drummer

2024

Appl Compos Mater

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Hybrid components consisting of continuous fiber reinforced thermoplastic (CFRT) and steel components exhibit promising potential in advanced lightweight construction. However, the joining operation presents a significant challenge due to the materials’ distinct physical and chemical properties. This paper studies a joining method in which dual pin arrays protruding from the surface of the metal component are inserted into the locally heated CFRT component to create a form-fitting joint. The primary objective is to scrutinize the influence of various CFRT materials on joint formation and quantify the resulting properties. The fiber type (glass and carbon) and fiber architecture (unidirectional and bidirectional reinforcement) are varied. All materials could successfully be joined via the direct pin pressing process, while depending on the CFRT material, distinct characteristic fiber morphologies could be identified. Bidirectionally reinforced carbon fiber reinforced samples showed the highest overall strength, while unidirectionally glass fiber reinforced samples showed the highest energy absorption and second highest ultimate strength.

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Joining of CFRT-steel hybrid parts via hole-forming and subsequent pin caulking

Römisch

Popp

Drummer

et al. 2021

Prod. Eng. Res. Devel.

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In times of increasing global warming, the awareness of the necessity for significant CO2 reduction is growing. Especially in the transport and aerospace sector, lightweight construction has potential to achieve emission reduction goals by reducing the overall vehicle weight. Thereby, adding lightweight fibre-reinforced composites to materials such as steel and aluminium is used to achieve weight savings. Furthermore, continuous-fibre-reinforced thermoplastics (CFRTs) begin to replace more traditional thermoset thermoplastics due to their easier bulk production and uncomplicated storage. Hybrid parts often consist of a CFRT and a higher strength metal component. Here, the joining process poses the main challenge, due to different chemical and physical properties of the components. In the current state of the art, riveted and bolted joints are commonly used, leading to increased weight due to auxiliary elements and requiring precise bolt holes often destroying load-bearing fibres. Joining with cold formed pin structures is an innovative and versatile joining process, which avoids the need for auxiliary elements. These pins are subsequently inserted in warm formed holes in the CFRT component and then caulked to create a form-fitting hybrid joint. To obtain a fundamental understanding of this joining process, hole-forming and pin-caulking, are investigated in this study. First, the hole-forming with IR-radiation is investigated with regard to suitable process parameters and resulting fibre morphology. The formed holes are consequently mechanically characterized. Second, the caulking-process is investigated by iteratively upsetting a pin and subsequently measuring the geometry. Based on these findings two different suitable caulking degrees are defined and samples for mechanical as well as microscopic investigations are manufactured. The created joints are first investigated via micro-sections and reflected light microscopy to identify possible damage in the CFRT component, which can result from the pin caulking process. Second, a mechanical characterisation under shear load as well as pin extraction loads normal to the sample surface is conducted and the normal load tests are compared with the bearing strength of CFRT samples.

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Mechanical joining without auxiliary element by cold formed pins for multi-material-systems

Cited by 18 publications

References 6 publications

Fiber Orientation Mechanism of Continuous Fiber Reinforced Thermoplastics Hybrid Parts Joined with Metallic Pins

Fiber Orientation Mechanism of Continuous Fiber Reinforced Thermoplastics Hybrid Parts Joined with Metallic Pins

Influence of the Textile Reinforcement on the Joint Formation of Pin-Joined Composite/Metal Parts

Joining of CFRT-steel hybrid parts via hole-forming and subsequent pin caulking

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