Further development of a numerical method for analyzing the load capacity of clinched joints in versatile process chains

Bielak, Christian Roman; Böhnke, Max; Bobbert, Mathias; Meschut, Gerson

doi:10.25518/esaform21.4298

Cited by 13 publications

(15 citation statements)

References 3 publications

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“…It should be noted that for the mixed steel-aluminum joint, the material combinations AJ2 and CJ2 cannot be investigated because the clinched joints exhibit neck fractures. This phenomenon has already been investigated and described in detail by Bielak et al 14…”

Section: Resultsmentioning

confidence: 67%

“…There is a negative correlation between the neck thickness and the interlock, whereby the sheet thickness reduction has a stronger influence on the neck thickness and the interlock than the pre-strengthening due to the pre-strain. This method has been further developed by Bielak et al 14 to numerically investigate the influence of defined pre-deformation of the joining parts on the load-bearing behavior under shear tensile loading. Quality-relevant parameters of clinched joints as well as the maximum transmittable force under shear load were determined.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints

Böhnke

Bielak

Klassen

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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Destructive testing methods are used to determine the joint characteristics of mechanical joining technologies by testing the joints under different types of loads. In real load cases, however, combined loading conditions arise in complex structures that cannot be investigated experimentally at present. The objective of this study is to adapt a so-called L-specimen geometry for mechanical joints to introduce combined peel and shear tensile loading, taking into account plastic pre-deformation of the joined parts. A new specimen geometry is presented to investigate three different clinched joints using different materials, namely HCT590X as well as EN AW-6014 T4. The load capacity behavior, as well as the failure behavior, is analyzed based on failure modes for pure shear, pure peel, and combined loading. Furthermore, the L-specimen is investigated by numerical simulation and compared with the experimental results.

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Section: Resultsmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints

Böhnke

Bielak

Klassen

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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“…3 Rotation mapping from a 2D rotational symmetric to a 3D model hardening caused by the joining process of the material. The procedure is described in more detail in [18].…”

Section: D-modell Rotation and Strain/stress Mappingmentioning

confidence: 99%

Numerical investigation of the clinched joint loadings considering the initial pre-strain in the joining area

Martin

Bielak

Bobbert

et al. 2022

Prod. Eng. Res. Devel.

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The components of a body in white consist of many individual thin-walled sheet metal parts, which usually are manufactured in deep-drawing processes. In general, the conditions in a deep-drawing process change due to changing tribology conditions, varying degrees of spring back, or scattering material properties in the sheet blanks, which affects the resulting pre-strain. Mechanical joining processes, especially clinching, are influenced by these process-related pre-strains. The final geometric shape of a clinched joint is affected to a significant level by the prior material deformation when joining with constant process parameters. That leads to a change in the stiffness and force transmission in the clinched joint due to the different geometric dimensions, such as interlock, neck thickness and bottom thickness, which directly affect the load bearing capacity. Here, the influence of the pre-straining in the deep drawing process on the force distribution in clinch points in an automotive assembly is investigated by finite-element models numerically. In further studies, the results are implemented in an optimization tool for designing clinched components. The methodology starts with a pre-straining of metal sheets. This step is followed by 2D rotationally symmetric forming simulations of the joining process. The resulting mesh of each forming simulation is rotated and 3D models are obtained. The clinched joint solid model with pre-strains is used further to determine the joint stiffnesses. With the simulation of the same test set-up with an equivalent point-connector model, the equivalent stiffness for each pre-strain combination is determined. Simulations are performed on a clinched component to assess the influence of pre-strain and sheet thinning on the clinched joint loadings by using the equivalent stiffnesses. The investigations clearly show that for the selected component, the loadings at the clinch points are dependent on the sheet thinning and the stiffnesses due to pre-strain. The magnitude of the influence varies depending on the quantity considered. For example, the shear force is more sensitive to the joint stiffness than to the sheet thinning.

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“…for body in white applications. 1 A widely used joining process is clinching, which does not require any additional auxiliary joining element. 2 In addition to the initial semifinished product properties, each of these operations influences the resulting properties of the parts and thus the subsequent manufacturing steps.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, such joining processes are highly sensitive to changes in the properties of the components to be joined. 4 In Bielak et al 1 it was shown that preforming has an influence on the joinability and that this affects the load-bearing capacity. To ensure a consistent joint quality and thus component quality, the alteration of the component properties must be taken into account in the design of clinched joints.…”

Section: Introductionmentioning

confidence: 99%

Consideration of the manufacturing history of sheet metal components for the adaptation of a clinching process

Heyser

Wiesenmayer

Frey

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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The process chain for the manufacturing of sheet metal components in mass production includes various cutting and forming operations, which influence the resulting properties of the parts and therefore subsequent manufacturing steps, such as clamping and joining. It is shown that clamping of the components leads to superimposed residual stresses and geometry changes. Therefore, the part properties differ from the initial state of the semifinished products, which has to be considered in the design of clinched joints. This paper presents an approach for coupled determination of the properties of semifinished and finished parts during deep drawing and clamping as well as their effects on the joint quality during clinching. One method for the effective and efficient determination of the properties of semifinished products and components during production is using process data from the preceding manufacturing processes, which is concretely presented in this work. In addition to the interconnection of the entire production chain, it is necessary to define relevant process data for each individual manufacturing step and to correlate the data with the material properties reliably. Therefore, the cross-process interactions of different steps of the process chain for the manufacturing of sheet metal components and the effect of process variations on subsequent manufacturing steps are investigated. Consequently, the boundary conditions for a mechanical joining process based on data from preceding process steps can be predicted.

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Further development of a numerical method for analyzing the load capacity of clinched joints in versatile process chains

Cited by 13 publications

References 3 publications

Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints

Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints

Numerical investigation of the clinched joint loadings considering the initial pre-strain in the joining area

Consideration of the manufacturing history of sheet metal components for the adaptation of a clinching process

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