Joining with versatile joining elements formed by friction spinning

Wischer, Christian; Wiens, Eugen; Homberg, Werner

doi:10.1016/j.jajp.2021.100060

Cited by 6 publications

(2 citation statements)

References 7 publications

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“…By combining these materials in a strategic manner, engineers can create a structure that is both lightweight and strong, while also meeting safety and comfort standards [2]. This approach allows for improved fuel efficiency and performance, while also addressing concerns related to passenger safety and comfort [3,4].…”

Section: Introductionmentioning

confidence: 99%

Ductile Fracture Prediction in Hole Hemming of Aluminum and Magnesium Sheets

Kasaei,

Pereira,

Carbas

et al. 2023

Metals

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The present work proposes a suitable approach for predicting ductile fracture in a new joining process by plastic deformation called hole hemming. This process creates a combined form- and force-fit joint and enables the joining of lightweight materials with varying formability without requiring heating or auxiliary elements. In this process, the joinability of materials is limited by the occurrence of fracture in the outer sheet, highlighting the crucial need to accurately predict its damage during the process design phase. In this study, five different fracture criteria, including the McClintock, Rice–Tracey, Normalized Cockroft–Latham, and Brozzo and Modified Mohr–Coulomb (MMC) criteria, are examined during the joining of a challenging combination of lightweight materials (aluminum AA6082-T4 and magnesium AZ31). These criteria are calibrated by a hybrid experimental–numerical method using three tests with distinct stress states. These criteria are then implemented into the finite element model of the hole hemming process, utilizing an appropriate user subroutine. The results show that the flange edge of the outer sheet is the most prone region to fracture during the joining process, and a criterion must be able to model the fracture behavior of the material from uniaxial tension to shear to accurately predict fracture in this area. Among the examined criteria, only the MMC criterion was capable of such modeling and accurately predicted the critical displacement of the punch in the hemming stage with a negligible error (about 1%). On the other hand, the prediction accuracy of the other criteria varied significantly depending on the calibration test, resulting in errors ranging from 8.6% to 75.5%. The error of 8.6% was achieved with the Normalized Cockroft–Latham criterion calibrated by a uniaxial tension test. Thus, based on the results, the MMC criterion is recommended for ductile fracture prediction in the hole hemming process, offering valuable insights to assist in process design.

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Section: Introductionmentioning

confidence: 99%

Ductile Fracture Prediction in Hole Hemming of Aluminum and Magnesium Sheets

Kasaei,

Pereira,

Carbas

et al. 2023

Metals

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“…The first characterization focuses on pre-hole-free joining with adaptive friction elements. Initial investigations, which were carried out in [17], used aluminum as the initial material for the adaptive auxiliary joining elements employed to join pre-holed sheets to one another. For an efficient process design, these should be kept as lean as possible.…”

Section: Introductionmentioning

confidence: 99%

Further Development of an Adaptive Joining Technique Based on Friction Spinning to Produce Pre-Hole-Free Joints

Wischer

Homberg

2022

KEM

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Mechanical joining processes are an essential part of modern lightweight construction. They permit materials of different types to be joined in a way that is suitable for the loads involved. These processes reach their limits, however, as soon as the boundary conditions change. In most cases, these elements are specially adapted to the joining point and cannot be used universally. Changes require cost-intensive adaptation of both the element and the process control, thus making production more complex. This results in high costs due to the increased number of auxiliary joining element variants required and reduces the economic efficiency of mechanical joining. One approach to overcoming this issue is the use of adaptive auxiliary joining elements formed by friction spinning. This article presents the current state of research on pre-hole-free joining with adaptive joining elements. The overall process chain is illustrated, explained and analyzed. Special attention is paid to demonstrating the feasibility of pre-hole-free joining with adaptive joining elements. The chosen mechanical parameters are subsequently listed. Finally, a comprehensive outlook of the future development potential is derived.

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A contribution on versatile process chains: joining with adaptive joining elements, formed by friction spinning

Wischer

Homberg

2021

Prod. Eng. Res. Devel.

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Nowadays, manufacturing of multi-material structures requires a variety of mechanical joining techniques. Mechanical joining processes and joining elements are used to meet a wide range of requirements, especially on versatile process chains. Most of these are explicitly adapted to only one, specific application. This leads to a less flexibility process chain due to many different variants and high costs. Changes in the boundary conditions like sheet thickness, or layers, lead to a need of re-design over the process and thus to a loss of time. To overcome this drawback, an innovative approach can be the use of individually manufactured and application-adapted joining elements (JE), the so-called Friction Spun Joint Connectors (FSJC). This new approach is based on defined, friction-induced heat input during the manufacturing and joining of the FSJC. This effect increases the formability of the initial material locally and permits them to be explicitly adapted to its application area. To gain a more detailed insight into the new process design, this paper presents a detailed characterization of the new joining technique with adaptive joining elements. The effects and interactions of relevant process variables onto the course and joining result is presented and described. The joining process comprises two stages: the manufacturing of FSJC from uniform initial material and the adaptive joining process itself. The following contribution presents the results of ongoing research work and includes the process concept, process properties and the results of experimental investigations. New promising concepts are presented and further specified. These approaches utilize the current knowledge and expand it systematically to open new fields of application.

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Joining with versatile joining elements formed by friction spinning

Cited by 6 publications

References 7 publications

Ductile Fracture Prediction in Hole Hemming of Aluminum and Magnesium Sheets

Ductile Fracture Prediction in Hole Hemming of Aluminum and Magnesium Sheets

Further Development of an Adaptive Joining Technique Based on Friction Spinning to Produce Pre-Hole-Free Joints

A contribution on versatile process chains: joining with adaptive joining elements, formed by friction spinning

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