2021
Nagel, Lukas; Herwig, Alexander; Schmidt, Carsten; Horst, Peter
Numerical Investigation of Residual Stresses in Welded Thermoplastic CFRP Structures Artikel
In: Journal of Composites Science, Bd. 5, Nr. 2021, S. 45, 2021, ISBN: 2504-477X.
Abstract | Links | BibTeX | Schlagwörter: Joining, Residual Stress
@article{jcs5020045,
title = {Numerical Investigation of Residual Stresses in Welded Thermoplastic CFRP Structures},
author = {Lukas Nagel and Alexander Herwig and Carsten Schmidt and Peter Horst},
editor = {MDPI},
url = {https://www.mdpi.com/2504-477X/5/2/45},
doi = {10.3390/jcs5020045},
isbn = {2504-477X},
year = {2021},
date = {2021-02-02},
journal = {Journal of Composites Science},
volume = {5},
number = {2021},
pages = {45},
abstract = {Using thermoplastics as the matrix in carbon fiber-reinforced polymers (CFRP) offers the possibility to make use of welded joints, which results in weight savings compared to conventional joining methods using mechanical fasteners. In this paper, the resulting temperature distribution in the material due to resistance welding is investigated by transient finite element (FE) simulations. To examine the effects on the component structure, a numerical modeling approach is created, which allows determining the residual stresses caused by the welding process. It is shown that the area of the structure, especially near the joining zone, is highly affected by the process, especially in terms of residual stresses. In particular, the stresses perpendicular to the fiber direction show failure relevant values up to a maximum of 221 MPa, which might lead to the formation of microcracks in the matrix. In turn, that is assumed to be critical in terms of the fatigue of welded composite structures. Thus, the suggested modeling approach provides residual stresses that can be used to determine their effects on the strength, structural stability, and fatigue of such composite structures. In a subsequent step, these findings could play an important role in the design process of thermoplastic composite structures.
},
keywords = {Joining, Residual Stress},
pubstate = {published},
tppubtype = {article}
}
Using thermoplastics as the matrix in carbon fiber-reinforced polymers (CFRP) offers the possibility to make use of welded joints, which results in weight savings compared to conventional joining methods using mechanical fasteners. In this paper, the resulting temperature distribution in the material due to resistance welding is investigated by transient finite element (FE) simulations. To examine the effects on the component structure, a numerical modeling approach is created, which allows determining the residual stresses caused by the welding process. It is shown that the area of the structure, especially near the joining zone, is highly affected by the process, especially in terms of residual stresses. In particular, the stresses perpendicular to the fiber direction show failure relevant values up to a maximum of 221 MPa, which might lead to the formation of microcracks in the matrix. In turn, that is assumed to be critical in terms of the fatigue of welded composite structures. Thus, the suggested modeling approach provides residual stresses that can be used to determine their effects on the strength, structural stability, and fatigue of such composite structures. In a subsequent step, these findings could play an important role in the design process of thermoplastic composite structures.
2018
Herwig, Alexander; Horst, Peter; Schmidt, Carsten; Pottmeyer, Florentin; Weidenmann, Kay André
In: Production Engineering, 2018, ISSN: 1863-7353.
Abstract | Links | BibTeX | Schlagwörter: Embedded Load Introduction Element, Fiber-Metal Laminate, Joining, Polymer-matrix composites (PMCs)
@article{Herwig2018,
title = {Design and mechanical characterisation of a layer wise build AFP insert in comparison to a conventional solution},
author = {Alexander Herwig and Peter Horst and Carsten Schmidt and Florentin Pottmeyer and Kay André Weidenmann},
editor = {Springer Berlin Heidelberg},
url = {https://link.springer.com/article/10.1007%2Fs11740-018-0815-2},
doi = {https://doi.org/10.1007/s11740-018-0815-2},
issn = {1863-7353},
year = {2018},
date = {2018-03-06},
journal = {Production Engineering},
abstract = {Joining methods that present a detachable connection of thin walled fiber reinforced plastic (FRP) structures greatly increase the proliferation of lightweight FRP-parts. This paper describes the design of a new layer wise build insert solution named multilayer insert (MLI) in a comparative study in terms of mechanical performance. The MLI is designed to be easily integrable into existing automated fiber placement processes. The mechanical characteristics and damage behavior of the MLI is compared with a commercially available insert serving as reference. Comparable results are obtained by testing the specimen in the same test setup. Both, the results of the MLI and the reference specimen show that a geometrical optimization is able to change the failure modes of the connection thereby keeping the surrounding FRP intact while improving the mechanical performance of the entire component.},
keywords = {Embedded Load Introduction Element, Fiber-Metal Laminate, Joining, Polymer-matrix composites (PMCs)},
pubstate = {published},
tppubtype = {article}
}
Joining methods that present a detachable connection of thin walled fiber reinforced plastic (FRP) structures greatly increase the proliferation of lightweight FRP-parts. This paper describes the design of a new layer wise build insert solution named multilayer insert (MLI) in a comparative study in terms of mechanical performance. The MLI is designed to be easily integrable into existing automated fiber placement processes. The mechanical characteristics and damage behavior of the MLI is compared with a commercially available insert serving as reference. Comparable results are obtained by testing the specimen in the same test setup. Both, the results of the MLI and the reference specimen show that a geometrical optimization is able to change the failure modes of the connection thereby keeping the surrounding FRP intact while improving the mechanical performance of the entire component.