@article{66457,
  abstract     = {{<jats:title>Abstract</jats:title>
                  <jats:p>The service life of fatigue-loaded components that already contain manufacturing‑induced microcracks is primarily governed by the direction and the rate of fatigue-crack growth. When multiple loading components (e.g., tension, compression, shear) act simultaneously but not in temporal synchrony, out‑of‑phase mixed‑mode conditions occur. Such loadings are typical for automotive chassis parts and mechanically joined sheet‑metal assemblies. For optimized design of structural components, the crack kinking angle that occurs under mixed‑mode loading must be predicted as accurately as possible. At present, however, this is still challenging for out‑of‑phase loading conditions. To investigate the associated crack kinking behavior, a novel Compact‑Tension‑Shear‑Mini (CTSM) specimen was developed, enabling controlled generation of plane out-of-phase mixed-mode loading states. Experiments were performed under various combinations of cyclic and static mode I and mode II load components and compared with the analytical predictions of the Out-of-Phase Mixed-Mode (OMM) concept. The measured crack kinking angles showed very good agreement with the predicted values, with mean deviations of only a few degrees, demonstrating the validity and reproducibility of the approach. These findings confirm the applicability of the OMM concept for describing fatigue‑crack propagation under non‑proportional mixed‑mode loading and provide a basis for fatigue‑life assessment of clinched joints and other cyclic multi-axially loaded components.</jats:p>}},
  author       = {{Krome, Sven and Kullmer, Gunter and Weiß, Deborah and Duffe, Tobias and Ostwald, Richard}},
  issn         = {{2731-6564}},
  journal      = {{Discover Mechanical Engineering}},
  number       = {{1}},
  publisher    = {{Springer Science and Business Media LLC}},
  title        = {{{Experimental determination of kinking angles with out-of-phase mixed-mode loading by means of a novel specimen geometry}}},
  doi          = {{10.1007/s44245-026-00236-5}},
  volume       = {{5}},
  year         = {{2026}},
}

@article{66673,
  abstract     = {{<jats:p>Investigating crack growth in sheet metal originating from clinched joints is a major part of predicting the service life of mechanically joined structures. Clinching allows different materials to be joined together. A key task in this context is to perform crack growth simulations in the vicinity of clinched joints considering different load and environmental conditions. This requires formulaic descriptions of the fatigue crack growth rate curves for the materials used. For this purpose, fatigue crack growth rate curves for different R-ratios and temperatures are determined experimentally. Generally, these fatigue crack growth rate curves can be described very well using a novel two-part exponential approach for the formulaic description of fatigue crack growth rate curves developed at Applied Mechanics of Paderborn University (FAM). In this case, three parameters are sufficient to describe the fatigue crack growth rate curves. For the material HCT590X, which is frequently used in clinched joints, it is shown as an example how the parameters vary with the R-ratio and the temperature. In addition, at high crack growth rates, a significant rise in the fatigue crack growth rate curve sometimes occurs at both low and high temperatures. To account for this feature, the two-part exponential approach can be expanded to include a third part.</jats:p>}},
  author       = {{Kullmer, Gunter and Krome, Sven and Weiß, Deborah and Schramm, Britta and Ostwald, Richard}},
  issn         = {{2075-4701}},
  journal      = {{Metals}},
  number       = {{8}},
  publisher    = {{MDPI AG}},
  title        = {{{Influence of the R-Ratio and the Temperature on the Coefficients of a Novel Exponential Approach for the Formulaic Description of Fatigue Crack Growth Rate Curves}}},
  doi          = {{10.3390/met16080835}},
  volume       = {{16}},
  year         = {{2026}},
}

@inproceedings{58878,
  author       = {{Buczek, Moritz and Duffe, Tobias and Kullmer, Gunter and Tews, Karina and Teutenberg, Dominik and Meschut, Gerson}},
  booktitle    = {{25. Kolloquium: Gemeinsame Forschung in der Klebtechnik}},
  location     = {{Köln}},
  title        = {{{Bruchmechanisches Schnittebenenkonzept zur lebensdauergerechten Auslegung von hyperelastischen Klebverbindungen bei multiaxialen und variablen Belastungsamplituden}}},
  year         = {{2025}},
}

@inproceedings{65172,
  abstract     = {{<jats:p>Abstract. The process of joining is used in numerous sectors of the manufacturing industry, where constructions composed of individual components or metal sheets are combined to form complex structures. A straightforward and pervasive approach for joining materials of disparate natures and coated surfaces is clinching. During the clinching process, plastic deformation, residual stresses and damage are introduced into the joint. Due to time-varying service loads cracks can initiate and propagate in the vicinity of the joint which limits the lifetime of the clinched structure. In order to prevent those damage cases, it is crucial to perform fracture mechanical evaluation of cracks in the joint region. Therefore, this publication deals with the question of how plastic deformation, residual stresses and damage need to be considered for the assessment of a crack. For this purpose, simple substitute models are employed to illustrate the principles based on the clinching application example.</jats:p>}},
  author       = {{Weiß, Deborah and Duffe, Tobias and Joy, Tintu David and Kullmer, Gunter}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Consideration of residual stresses and damage in the fracture mechanical investigation of mechanically joined structures}}},
  doi          = {{10.21741/9781644903551-28}},
  volume       = {{52}},
  year         = {{2025}},
}

@misc{63764,
  author       = {{Weiß, Deborah and Krome, Sven and Duffe, Tobias and Kullmer, Gunter and Ostwald, Richard}},
  publisher    = {{LibreCat University}},
  title        = {{{Experimentelle Ermittlung von Rissablenkungswinkeln bei außerphasiger Mixed-Mode-Belastung mittels einer neuartigen Probengeometrie}}},
  doi          = {{https://doi.org/10.48447/BR-2025-490}},
  year         = {{2025}},
}

@misc{65221,
  author       = {{Kullmer, Gunter and Weiß, Deborah and Duffe, Tobias and Schramm, Britta and Ostwald, Richard}},
  publisher    = {{LibreCat University}},
  title        = {{{BESCHREIBUNG DES R- UND DES TEMPERATUREINFLUSSES SOWIE DES EINLAUFVERHALTENS BEI EXPERIMENTELL BESTIMMTEN RISSFORTSCHRITTSKURVEN MIT DEM EXPONENTIALANSATZ}}},
  doi          = {{https://doi.org/10.48447/BR-2025-492}},
  year         = {{2025}},
}

@article{63662,
  abstract     = {{The accurate prediction of crack initiation and propagation is essential for assessing the structural integrity of mechanically joined components and other complex assemblies. To overcome the limitations of existing finite element tools, a modular Python framework has been developed to automate three-dimensional crack growth simulations. The program combines geometric reconstruction, adaptive remeshing, and the numerical evaluation of fracture mechanics parameters within a single, fully automated workflow. The framework builds on open-source components and remains solver-independent, enabling straightforward integration with commercial or research finite element codes. A dedicated sequence of modules performs all required steps, from mesh separation and crack insertion to local submodeling, stress and displacement mapping, and iterative crack-front update, without manual interaction. The methodology was verified using a mini-compact tension (Mini-CT) specimen as a benchmark case. The numerical results demonstrate the accurate reproduction of stress intensity factors and energy release rates while achieving high computational efficiency through localized refinement. The developed approach provides a robust basis for crack growth simulations of geometrically complex or residual stress-affected structures. Its high degree of automation and flexibility makes it particularly suited for analyzing cracks in clinched and riveted joints, supporting the predictive design and durability assessment of joined lightweight structures.}},
  author       = {{Krome, Sven and Duffe, Tobias and Kullmer, Gunter and Schramm, Britta and Ostwald, Richard}},
  issn         = {{2076-3417}},
  journal      = {{Applied Sciences}},
  number       = {{1}},
  publisher    = {{MDPI AG}},
  title        = {{{Validation and Verification of Novel Three-Dimensional Crack Growth Simulation Software GmshCrack3D}}},
  doi          = {{10.3390/app16010384}},
  volume       = {{16}},
  year         = {{2025}},
}

@article{51737,
  author       = {{Kullmer, Gunter and Weiß, Deborah and Schramm, Britta}},
  issn         = {{0013-7944}},
  journal      = {{Engineering Fracture Mechanics}},
  keywords     = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
  publisher    = {{Elsevier BV}},
  title        = {{{An alternative and robust formulation of the fatigue crack growth rate curve for long cracks}}},
  doi          = {{10.1016/j.engfracmech.2023.109826}},
  volume       = {{296}},
  year         = {{2024}},
}

@inproceedings{52212,
  author       = {{Tews, Karina and Teutenberg, Dominik and Meschut, Gerson and Buczek, Moritz and Duffe, Tobias and Kullmer, Gunter}},
  booktitle    = {{24. Kolloquium: Gemeinsame Forschung in der Klebtechnik}},
  location     = {{Köln}},
  title        = {{{Bruchmechanisches Schnittebenenkonzept zur lebensdauergerechten Auslegung von hyperelastischen Klebverbindungen bei multiaxialen und variablen Belastungsamplituden}}},
  year         = {{2024}},
}

@inproceedings{53394,
  author       = {{Kullmer, Gunter and Weiß, Deborah and Schramm, Britta}},
  location     = {{Kassel}},
  publisher    = {{Deutscher Verband für Materialforschung und –prüfung e.V.}},
  title        = {{{Weiterentwicklung des Exponentialansatzes zur Beschreibung von Rissfortschrittskurven}}},
  doi          = {{10.48447/BR-2024-369}},
  year         = {{2024}},
}

@inproceedings{51739,
  author       = {{Weiß, Deborah and Duffe, Tobias and Buczek, Moritz and Kullmer, Gunter and Schramm, Britta}},
  location     = {{Berlin}},
  publisher    = {{Deutscher Verband für Materialforschung und -prüfung e.V.}},
  title        = {{{Bruchmechanische Untersuchung des Dualphasenstahls HCT590X unter Temperatureinfluss}}},
  doi          = {{10.48447/WP-2023-244}},
  year         = {{2023}},
}

@article{41906,
  abstract     = {{<jats:title>Abstract</jats:title><jats:sec>
                <jats:title>Background</jats:title>
                <jats:p>Due to the steadily increasing life expectancy of the population, the need for medical aids to maintain the previous quality of life is growing. The basis for independent mobility is a functional locomotor system. The hip joint can be so badly damaged by everyday wear or accelerated by illness that reconstruction by means of endoprostheses is necessary.</jats:p>
              </jats:sec><jats:sec>
                <jats:title>Results</jats:title>
                <jats:p>In order to ensure a high quality of life for the patient after this procedure as well as a long service life of the prosthesis, a high-quality design is required, so that many different aspects have to be taken into account when developing prostheses. Long-term medical studies show that the service life and operational safety of a hip prosthesis by best possible adaptation of the stiffness to that of the bone can be increased. The use of additive manufacturing processes enables to specifically change the stiffness of implant structures.</jats:p>
              </jats:sec><jats:sec>
                <jats:title>Conclusions</jats:title>
                <jats:p>Reduced implant stiffness leads to an increase in stress in the surrounding bone and thus to a reduction in bone resorption. Numerical methods are used to demonstrate this fact in the hip implant developed. The safety of use is nevertheless ensured by evaluating and taking into account the stresses that occur for critical load cases. These results are a promising basis to enable longer service life of prostheses in the future.</jats:p>
              </jats:sec>}},
  author       = {{Risse, Lena and Woodcock, Steven Clifford and Brüggemann, Jan-Peter and Kullmer, Gunter and Richard, Hans Albert}},
  issn         = {{1475-925X}},
  journal      = {{BioMedical Engineering OnLine}},
  keywords     = {{Radiology, Nuclear Medicine and imaging, Biomedical Engineering, General Medicine, Biomaterials, Radiological and Ultrasound Technology}},
  number       = {{1}},
  publisher    = {{Springer Science and Business Media LLC}},
  title        = {{{Stiffness optimization and reliable design of a hip implant by using the potential of additive manufacturing processes}}},
  doi          = {{10.1186/s12938-022-00990-z}},
  volume       = {{21}},
  year         = {{2022}},
}

@inproceedings{29853,
  author       = {{Tews, Karina and Aubel, Tobias and Teutenberg, Dominik and Meschut, Gerson and Duffe, Tobias and Kullmer, Gunter}},
  booktitle    = {{22. Kolloquium: Gemeinsame Forschung in der Klebtechnik}},
  title        = {{{Methodenentwicklung zur numerischen Lebensdauerprognose von hyperelastischen Klebverbindungen infolge zyklischer Beanspruchung mittels bruchmechanischer Ansätze }}},
  year         = {{2022}},
}

@inproceedings{41907,
  author       = {{Woodcock, Steven Clifford and Schramm, Britta and Kullmer, Gunter and Richard, Hans Albert}},
  location     = {{Rostock}},
  publisher    = {{Deutscher Verband für Materialforschung und -prüfung e.V.}},
  title        = {{{Bewertung der Knochen-Schraube Verbindung im Auszugtest und unter physiologischer Belastung in der Finite Elemente Methode}}},
  year         = {{2022}},
}

@article{32392,
  author       = {{Duffe, Tobias and Kullmer, Gunter and Tews, Karina and Aubel, Tobias and Meschut, Gerson}},
  journal      = {{Theoretical and Applied Fracture Mechanics}},
  title        = {{{Global energy release rate of small penny-shaped cracks in hyperelastic materials under general stress conditions}}},
  doi          = {{10.1016/j.tafmec.2022.103461}},
  year         = {{2022}},
}

@inproceedings{33088,
  author       = {{Duffe, Tobias and Tews, Karina and Kullmer, Gunter and Meschut, Gerson}},
  booktitle    = {{ECF23, European Conference on Fracture 2022}},
  title        = {{{Fracture mechanical concept to predict crack nucleation in elastic adhesive joints}}},
  year         = {{2022}},
}

@article{33495,
  author       = {{Duffe, Tobias and Tews, Karina and Aubel, Tobias and Meschut, Gerson and Kullmer, Gunter}},
  journal      = {{Fachzeitschrift für Schweißen und verwandte Verfahren}},
  number       = {{9}},
  pages        = {{570--576}},
  publisher    = {{DVS}},
  title        = {{{Numerische Lebensdauerprognose von hyperelastischen Klebverbindungen mit einem bruchmechanischen Ansatz}}},
  volume       = {{74}},
  year         = {{2022}},
}

@article{34224,
  abstract     = {{Crack growth in structures depends on the cyclic loads applied on it, such as mechanical, thermal and contact, as well as residual stresses, etc. To provide an accurate simulation of crack growth in structures, it is of high importance to integrate all kinds of loading situations in the simulations. Adapcrack3D is a simulation program that can accurately predict the propagation of cracks in real structures. However, until now, this three-dimensional program has only considered mechanical loads and static thermal loads. Therefore, the features of Adapcrack3D have been extended by including contact loading in crack growth simulations. The numerical simulation of crack propagation with Adapcrack3D is generally carried out using FE models of structures provided by the user. For simulating models with contact loading situations, Adapcrack3D has been updated to work with FE models containing multiple parts and necessary features such as coupling and surface interactions. Because Adapcrack3D uses the submodel technique for fracture mechanical evaluations, the architecture of the submodel is also modified to simulate models with contact definitions between the crack surfaces. This paper discusses the newly implemented attribute of the program with the help of illustrative examples. The results confirm that the contact simulation in Adapcrack3D is a major step in improving the functionality of the program.}},
  author       = {{Joy, Tintu David and Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}},
  issn         = {{2076-3417}},
  journal      = {{Applied Sciences}},
  keywords     = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}},
  number       = {{15}},
  publisher    = {{MDPI AG}},
  title        = {{{Further Development of 3D Crack Growth Simulation Program to Include Contact Loading Situations}}},
  doi          = {{10.3390/app12157557}},
  volume       = {{12}},
  year         = {{2022}},
}

@inproceedings{30726,
  author       = {{Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}},
  booktitle    = {{Procedia Structural Integrity}},
  issn         = {{2452-3216}},
  keywords     = {{General Engineering, Energy Engineering and Power Technology}},
  location     = {{online}},
  pages        = {{139--147}},
  publisher    = {{Elsevier BV}},
  title        = {{{Influence of plane mixed-mode loading on the kinking angle of clinchable metal sheets}}},
  doi          = {{10.1016/j.prostr.2022.03.082}},
  volume       = {{39}},
  year         = {{2022}},
}

@article{34246,
  author       = {{Kullmer, Gunter and Weiß, Deborah and Schramm, Britta}},
  issn         = {{0013-7944}},
  journal      = {{Engineering Fracture Mechanics}},
  keywords     = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
  publisher    = {{Elsevier BV}},
  title        = {{{Development of a method for the separate measurement of the growth of internal crack tips by means of the potential drop method}}},
  doi          = {{10.1016/j.engfracmech.2022.108899}},
  year         = {{2022}},
}