Falk Heinecke

Bio: Falk Heinecke is an academic researcher from German Aerospace Center. The author has contributed to research in topics: Finite element method & Peridynamics. The author has an hindex of 5, co-authored 14 publications receiving 71 citations.

Manufacturing-Induced Imperfections in Composite Parts Manufactured via Automated Fiber Placement

Abstract: The automated fiber placement process (AFP) enables the manufacturing of large and geometrical complex fiber composite structures with high quality at low cycle times. Although the AFP process is highly accurate and reproducible, manufacturing induced imperfections in the produced composite structure occur. This review summarizes and classifies typical AFP-related manufacturing defects. Several methodologies for evaluating the effects of such manufacturing defects from the literature are reviewed. This review paper presents recent scientific contributions and discusses proposed experimental and simulation-based methodologies. Among the identified ten defect classes, gaps and overlaps are predominant. This paper focuses then on methods for modelling and assessing gaps and overlaps. The state of the art in modelling gaps and overlaps and assessing their influence on mechanical properties is presented. Finally, research gaps and remaining issues are identified.

Automated model generation and sizing of aircraft structures

Abstract: Purpose To obtain a good start configuration in the early design phase, simulation tools are used to create a large number of product designs and to evaluate their performance. To reduce the effort for the model generation, analysis and evaluation, a design environment for thin-walled lightweight structures (DELiS) with the focus on structural mechanics of aircrafts has been developed. Design/methodology/approach The core of DELiS is a parametric model generator, which creates models of thin-walled lightweight structures for the aircraft preliminary design process. It is based on the common parametric aircraft configuration schema (CPACS), which is an abstract aircraft namespace. DELiS facilitates interfaces to several commercial and non-commercial finite element solvers and sizing tools. Findings The key principles and the advantages of the DELiS process are illustrated. Also, a convergence study of the finite element model of the wing and the fuselage and the result on the mass after the sizing process are shown. Due to the high flexibility of model generation with different levels of detail and the interface to the exchange database CPACS, DELiS is well suited to study the structural behaviour of different aircraft configurations in a multi-disciplinary design process. Originality/value The abstract definition of the object-oriented model allows several dimensions of variability, such as different fidelity levels, for the resulting structural model. Wings and fuselages can be interpreted as finite beam models, to calculate the global dynamic behaviour of a structure, or as finite shell models.

In-Situ Structural Evaluation during the Fibre Deposition Process of Composite Manufacturing

Abstract: Within the European funded project ECOMISE a new approach for composite manufacturing is developed. This approach provides key technologies for industry 4.0 in order to maximize process efficiency at reduced cost and time while maintaining structural requirements. In detail, process simulation methods, online process monitoring systems as well as methods for in-situ structural evaluation and process adjustment in case of process deviations are implemented and linked via databases. This paper describes the new overall concept as well as the specific in-situ structural evaluation approach, exemplarily applied to the fibre deposition process. Prior to manufacturing typical manufacturing features such as locally varying fibre orientation, gaps and overlaps are studied based on given knowledge from previous manufacturing as well as from process simulation. The effect of selected features on the structural properties is investigated for the expected parameter ranges. The real detected features are provided by an online monitoring system during the fibre deposition process. Based on these results an in-situ structural evaluation of detected features is performed already during manufacturing in combination with a decision making with respect to required part correction. The developed key technologies and tools for the in-situ evaluation process are presented, and their prototype application is shown during manufacturing of an aeronautic wing cover demonstrator.

Assessing the structural response of automated fibre placement composite structures with gaps and overlaps by means of numerical approaches

Abstract: Ecomise is a European funded project enhancing process and evaluation techniques for automated dry fibre placement (AFP), infusion/ injection (RTI/ RTM) and curing for the purpose of achieving less energy and material consumption, higher reproducibility, reduction waste and rework. The paper focuses on the automated dry fibre placement technique (AFP), in particular on the assessment of manufacturing induced gaps and overlaps within the composite laminate. The goal is to determine the effect of these manufacturing deviations on the material behaviour in terms of stiffness and strength in order to enable a so called “as-built” analysis. Three different approaches are investigated, an analytical (comparable to a rule of mixtures) and two numerical based approaches (“virtual test” and multi-scale analysis), which are applied to two different types of deviations, long narrow gaps and long wide gaps/ overlaps. The investigation reveals that there is a considerable effect on stiffness and strength caused by the investigated deviations. It is further found that depending on the modelling approach and the applied failure criterion (e.g. first ply failure, progressive damage) the resulting stiffness and strength properties are quite diverse. This study is not exhaustive, further investigations and validation with experimental data is to be done.

Parametric Model Generation and Sizing of Lightweight Structures for a Multidisciplinary Design Process

Abstract: The product development cycles in all parts of the industry become increasingly shorter. In spite of the shorter cycle time, the performance of a new product generation must be increased. In the early design process, simulation tools are used to create a large number of designs and to evaluate their performance. To reduce the effort for modeling and structure evaluation, a design environment for thin-walled lightweight structures (DELiS) with the focus on structure mechanics has been developed. The core of DELiS is a parametric model generator which creates models of lightweight thin-walled structures. It has been developed initially for the aircraft pre design process. Furthermore, due to its flexibility and the use of synergies to aircraft wings, wind turbine blades can also be generated with DELiS. Based on the same abstract database, it is possible to create models with variable level of detail. Exemplarily wings can be modeled as simplified beam, or in a fine wing model, stringers can be created using beam elements or smeared as an extra shell layer. With the support of several com-mercial finite element (FE) solvers many other applications can be used, such as sizing tools that require a specific FE solver. Thus, DELiS facilitates interfaces to these sizing tools. So forth it includes the modeling, the simulation and the evaluation process. Based on Python programming language it is platform independent and can access most major libraries. The structural description of a database is interpreted and transferred in an abstract object oriented data model. Therefore, new interfaces can be added conveniently, FE models can be derived smoothly and sizing results can be used to update the model easily. DELiS utilizes the common aircraft language CPACS (Common Parametric Aircraft Configuration Scheme) as input database for the model generation. It is developed by the German Aerospace Center (DLR) and allows the exchange of data between all disciplines in the aircraft design pro-cess. By interpreting this multidisciplinary aircraft language, all disciplines of the aircraft design process are able to communicate with the structural model in such problems. When searching for the game changing configuration of aircrafts or wind turbine blades, a wide design space must be supported. This design space consists of global (e.g. different configurations) as well as local (e.g. subcomponent properties) degrees of freedom. Thus, a modular and parametric design environment is advantageous. The paper shows the program architecture and the methodology of DELiS that enable the required variability. Examples of the model generation are given and the flexibility with respect to sizing tools is pointed out.

Manufacturing-Induced Imperfections in Composite Parts Manufactured via Automated Fiber Placement

Abstract: The automated fiber placement process (AFP) enables the manufacturing of large and geometrical complex fiber composite structures with high quality at low cycle times. Although the AFP process is highly accurate and reproducible, manufacturing induced imperfections in the produced composite structure occur. This review summarizes and classifies typical AFP-related manufacturing defects. Several methodologies for evaluating the effects of such manufacturing defects from the literature are reviewed. This review paper presents recent scientific contributions and discusses proposed experimental and simulation-based methodologies. Among the identified ten defect classes, gaps and overlaps are predominant. This paper focuses then on methods for modelling and assessing gaps and overlaps. The state of the art in modelling gaps and overlaps and assessing their influence on mechanical properties is presented. Finally, research gaps and remaining issues are identified.

Advanced robotics and additive manufacturing of composites: towards a new era in Industry 4.0

Abstract: In recent years, new revolutionary paradigms generally indicated using the term Industry 40, have been conceived and are progressively applied in several manufacturing systems to achieve a smarter