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Additive manufacturing, especially material extrusion (MEX), has received a lot of attention recently. The reasons for this are the numerous advantages compared to conventional manufacturing processes, which result in various new possibilities for product development and -design. By applying material layer by layer, parts with complex, load-path optimized geometries can be manufactured at neutral costs. To expand the application fields of MEX, high-strength and simultaneously lightweight materials are required which fulfill the requirements of highly resilient technical parts. For instance, the embedding of continuous carbon and flax fibers in a polymer matrix offers great potential for this. To achieve the highest possible variability with regard to the material combinations while ensuring simple and economical production, the fiber–matrix bonding should be carried out in one process step together with the actual parts manufacture. This paper deals with the adaptation and improvement of the 3D printer on the one hand and the characterization of 3D printed test specimens based on carbon and flax fibers on the other hand. For this purpose, the print head development for in-situ processing of contin uous fiber-reinforced parts with improved mechanical properties is described. It was determined that compared to neat polylactic acid (PLA), the continuous fiber-reinforced test specimens achieve up to 430% higher tensile strength and 890% higher tensile modulus for the carbon fiber reinforcement and an increase of up to 325% in tensile strength and 570% in tensile modulus for the flax fibers. Similar improvements in performance were achieved in the bending tests.
Sebastian Kuschmitz; Arne Schirp; Johannes Busse; Hagen Watschke; Claudia Schirp; Thomas Vietor. Development and Processing of Continuous Flax and Carbon Fiber-Reinforced Thermoplastic Composites by a Modified Material Extrusion Process. Materials 2021, 14, 2332 .
AMA StyleSebastian Kuschmitz, Arne Schirp, Johannes Busse, Hagen Watschke, Claudia Schirp, Thomas Vietor. Development and Processing of Continuous Flax and Carbon Fiber-Reinforced Thermoplastic Composites by a Modified Material Extrusion Process. Materials. 2021; 14 (9):2332.
Chicago/Turabian StyleSebastian Kuschmitz; Arne Schirp; Johannes Busse; Hagen Watschke; Claudia Schirp; Thomas Vietor. 2021. "Development and Processing of Continuous Flax and Carbon Fiber-Reinforced Thermoplastic Composites by a Modified Material Extrusion Process." Materials 14, no. 9: 2332.
Additive manufacturing (AM), widely known as 3D-printing, builds parts by adding material in a layer-by-layer process. This tool-less procedure enables the manufacturing of porous sound absorbers with defined geometric features, however, the connection of the acoustic behavior and the material’s micro-scale structure is only known for special cases. To bridge this gap, the work presented here employs machine-learning techniques that compute acoustic material parameters (Biot parameters) from the material’s micro-scale geometry. For this purpose, a set of test specimens is used that have been developed in earlier studies. The test specimens resemble generic absorbers by a regular lattice structure based on a bar design and allow a variety of parameter variations, such as bar width, or bar height. A set of 50 test specimens is manufactured by material extrusion (MEX) with a nozzle diameter of
Sebastian Kuschmitz; Tobias Ring; Hagen Watschke; Sabine Langer; Thomas Vietor. Design and Additive Manufacturing of Porous Sound Absorbers—A Machine-Learning Approach. Materials 2021, 14, 1747 .
AMA StyleSebastian Kuschmitz, Tobias Ring, Hagen Watschke, Sabine Langer, Thomas Vietor. Design and Additive Manufacturing of Porous Sound Absorbers—A Machine-Learning Approach. Materials. 2021; 14 (7):1747.
Chicago/Turabian StyleSebastian Kuschmitz; Tobias Ring; Hagen Watschke; Sabine Langer; Thomas Vietor. 2021. "Design and Additive Manufacturing of Porous Sound Absorbers—A Machine-Learning Approach." Materials 14, no. 7: 1747.
One possibility in order to manufacture products with very few restrictions in design freedom is additive manufacturing. For advanced acoustic design measures like Acoustic Black Holes (ABH), the layer-wise material deposition allows the continuous alignment of the mechanical impedance by different filling patterns and degrees of filling. In order to explore the full design potential, mechanical models are indispensable. In dependency on process parameters, the resulting homogenized material parameters vary. In previous investigations, especially for ABH structures, a dependency of the material parameters on the structure’s thickness can be observed. In this contribution, beams of different thicknesses are investigated experimentally and numerically in order to identify the material parameters in dependency on the frequency and the thickness. The focused material is polyactic acid (PLA). A parameter fitting is conducted by use of a 3D finite element model and it’s reduced version in a Krylov subspace. The results yield homogenized material parameters for the PLA stack as a function of frequency and thickness. An increasing Young’s modulus with increasing frequency and increasing thickness is observed. This observed effect has considerable influence and has not been considered so far. With the received parameters, more reliable results can be obtained.
Sebastian Rothe; Christopher Blech; Hagen Watschke; Thomas Vietor; Sabine C. Langer. Material Parameter Identification for Acoustic Simulation of Additively Manufactured Structures. Materials 2020, 14, 168 .
AMA StyleSebastian Rothe, Christopher Blech, Hagen Watschke, Thomas Vietor, Sabine C. Langer. Material Parameter Identification for Acoustic Simulation of Additively Manufactured Structures. Materials. 2020; 14 (1):168.
Chicago/Turabian StyleSebastian Rothe; Christopher Blech; Hagen Watschke; Thomas Vietor; Sabine C. Langer. 2020. "Material Parameter Identification for Acoustic Simulation of Additively Manufactured Structures." Materials 14, no. 1: 168.
Direct additive manufacturing (AM) of sensors has in recent years become possible, but still remains a largely unexplored area. This work proposes a novel resistive sensor design that utilizes the geometric freedom offered by AM, especially by material extrusion, to enable a customizable and amplified response to force and deformation. This is achieved by using a multi-material design made of an elastomer and an electrically conductive polymer that enables a physical shortening of the conductive path under compressive load through a specific definition of shape. A number of different variants of this novel sensor design are tested, measuring their mechanical and electrical behavior under compression. The results of these tests confirm a strong resistive response to mechanical loading. Furthermore, the results provide insight into the influencing factors of the design, i.e., the gap size between the conductive pathing and the stiffness of the sense element support structure are found to be primary influencing factors governing sensor behavior.
Hagen Watschke; Marijn Goutier; Julius Heubach; Thomas Vietor; Kay Leichsenring; Markus Böl. Novel Resistive Sensor Design Utilizing the Geometric Freedom of Additive Manufacturing. Applied Sciences 2020, 11, 113 .
AMA StyleHagen Watschke, Marijn Goutier, Julius Heubach, Thomas Vietor, Kay Leichsenring, Markus Böl. Novel Resistive Sensor Design Utilizing the Geometric Freedom of Additive Manufacturing. Applied Sciences. 2020; 11 (1):113.
Chicago/Turabian StyleHagen Watschke; Marijn Goutier; Julius Heubach; Thomas Vietor; Kay Leichsenring; Markus Böl. 2020. "Novel Resistive Sensor Design Utilizing the Geometric Freedom of Additive Manufacturing." Applied Sciences 11, no. 1: 113.
To be able to use finite element (FE) simulations in structural component development, experimental investigations for the characterization of the material properties are required to subsequently calibrate suitable material cards. In contrast to the commonly used computational and time-consuming method of parameter identification (PI) by using analytical and numerical optimizations with internal or commercial software, a more time-efficient method based on machine learning (ML) is presented. This method is applied to simulate the material behavior of additively manufactured specimens made of acrylonitrile butadiene styrene (ABS) under uniaxial stress in a structural simulation. By using feedforward artificial neural networks (FFANN) for the ML-based direct inverse PI process, various investigations were carried out on the influence of sampling strategies, data quantity and data preparation on the prediction accuracy of the NN. Furthermore, the results of hyperparameter (HP) search methods are presented and discussed and their influence on the prediction quality of the FFANN are critically evaluated. The investigations show that the NN-based method is applicable to the present use case and results in material parameters that lead to a lower error between experimental and calculated force-displacement curves than the commonly used optimization-based method.
Paul Meißner; Hagen Watschke; Jens Winter; Thomas Vietor. Artificial Neural Networks-Based Material Parameter Identification for Numerical Simulations of Additively Manufactured Parts by Material Extrusion. Polymers 2020, 12, 2949 .
AMA StylePaul Meißner, Hagen Watschke, Jens Winter, Thomas Vietor. Artificial Neural Networks-Based Material Parameter Identification for Numerical Simulations of Additively Manufactured Parts by Material Extrusion. Polymers. 2020; 12 (12):2949.
Chicago/Turabian StylePaul Meißner; Hagen Watschke; Jens Winter; Thomas Vietor. 2020. "Artificial Neural Networks-Based Material Parameter Identification for Numerical Simulations of Additively Manufactured Parts by Material Extrusion." Polymers 12, no. 12: 2949.
Additive manufacturing (AM) opens new possibilities for innovative product designs. However, due to a lack of knowledge and restrained creativity because of design fixations, design engineers do not take advantage of AM's design freedom. Especially multi-material AM provides new opportunities for functional integration that hardly considered in ideation. To overcome barriers in the development of solution ideas and utilizing such new design potentials, new design methods and tools are needed. Therefore, in this contribution, a methodological approach for a function-oriented provision of solution principles specific to material extrusion is presented. A tool is developed to facilitate effective guidance in developing solution ideas and to foster a realistic concretization by providing a combination of opportunistic and restrictive AM knowledge. Besides general levers of AM, process-specific design opportunities support the design engineers in exploiting AM's potentials, especially those who are not familiar with Design for AM. Finally, the applicability of the methodological approach is evaluated in an academic study by means of redesigning a hand prosthesis with a grab function.
Hagen Watschke; Sebastian Kuschmitz; Julius Heubach; Guido Lehne; Thomas Vietor. A Methodical Approach to Support Conceptual Design for Multi-Material Additive Manufacturing. Proceedings of the Design Society: International Conference on Engineering Design 2019, 1, 659 -668.
AMA StyleHagen Watschke, Sebastian Kuschmitz, Julius Heubach, Guido Lehne, Thomas Vietor. A Methodical Approach to Support Conceptual Design for Multi-Material Additive Manufacturing. Proceedings of the Design Society: International Conference on Engineering Design. 2019; 1 (1):659-668.
Chicago/Turabian StyleHagen Watschke; Sebastian Kuschmitz; Julius Heubach; Guido Lehne; Thomas Vietor. 2019. "A Methodical Approach to Support Conceptual Design for Multi-Material Additive Manufacturing." Proceedings of the Design Society: International Conference on Engineering Design 1, no. 1: 659-668.
Material composition complexity offered by material extrusion additive manufacturing offers new opportunities for function-driven part design. Nevertheless, since influencing factors on the interface strength between different materials are not well understood, this complexity is only used infrequently, in part, in design thereby restraining innovation. This paper proposes a systematical approach for identification and quantification of relevant adhesion phenomena that influence interface strength. For this reason, suited test specimen, which utilize the geometric freedom offered by additive manufacturing, are developed for roll peeling tests and peeling resistance of several combinations of rigid and flexible materials is determined. The results show that material choice especially regarding polarity as well as mechanical interlocking in regards to surface roughness and design features have high influence on the interface strength of multi-material parts manufactured by material extrusion. These results are explained through the relevant adhesion mechanisms that determine the interface strength in additively manufactured parts. Finally, criteria that predominantly affect interface strength are deduced and design recommendations for creating functional parts with ill-fitting material combinations are formulated.
Raphael Freund; Hagen Watschke; Julius Heubach; Thomas Vietor. Determination of Influencing Factors on Interface Strength of Additively Manufactured Multi-Material Parts by Material Extrusion. Applied Sciences 2019, 9, 1782 .
AMA StyleRaphael Freund, Hagen Watschke, Julius Heubach, Thomas Vietor. Determination of Influencing Factors on Interface Strength of Additively Manufactured Multi-Material Parts by Material Extrusion. Applied Sciences. 2019; 9 (9):1782.
Chicago/Turabian StyleRaphael Freund; Hagen Watschke; Julius Heubach; Thomas Vietor. 2019. "Determination of Influencing Factors on Interface Strength of Additively Manufactured Multi-Material Parts by Material Extrusion." Applied Sciences 9, no. 9: 1782.
Multi-material additive manufacturing offers new design freedom for functional integration and opens new possibilities in innovative part design, for instance, a local integration of electrically conductive structures or heat radiant surfaces. Detailed experimental investigations on materials with three different fillers (carbon black (CB), carbon nanotubes (CNT) and nano copper wires) were conducted to identify process-specific influencing factors on electrical conductivity and resistive heating. In this regard, raster angle orientation, extrusion temperature, speed and flow rate were investigated. A variation of the raster angle (0°, ±45°, and 90°) shows the highest influence on resistivity. An angle of 0° had the lowest electrical resistance and the highest temperature increase due to resistive heating. The material filled with nano copper wires showed the highest electrical conductivity followed by the CNT filled material and materials filled with CB. Both current–voltage characteristics and voltage-dependent heat distribution of the surface temperature were determined by using a thermographic camera. The highest temperature increase was achieved by the CNT filled material. The materials filled with CB and nano copper wires showed increased electrical resistance depending on temperature. Based on the experiments, solution principles and design rules for additively manufactured electrically conductive structures are derived.
Hagen Watschke; Karl Hilbig; Thomas Vietor. Design and Characterization of Electrically Conductive Structures Additively Manufactured by Material Extrusion. Applied Sciences 2019, 9, 779 .
AMA StyleHagen Watschke, Karl Hilbig, Thomas Vietor. Design and Characterization of Electrically Conductive Structures Additively Manufactured by Material Extrusion. Applied Sciences. 2019; 9 (4):779.
Chicago/Turabian StyleHagen Watschke; Karl Hilbig; Thomas Vietor. 2019. "Design and Characterization of Electrically Conductive Structures Additively Manufactured by Material Extrusion." Applied Sciences 9, no. 4: 779.
Multi-material additive manufacturing (AM) offers new design opportunities for functional integration and opens new possibilities in innovative part design, for example, regarding the integration of damping or conductive structures. However, there are no standardized test methods, and thus test specimens that provide information about the bonding quality of two materials printed together. As a result, a consideration of these new design potentials in conceptual design is hardly possible. As material extrusion (ME) allows easily combination of multiple polymeric materials in one part, it is chosen as an AM technique for this contribution. Based on a literature review of commonly used standards for polymer testing, novel test specimens are developed for the characterization of the bonding quality of two ME standard materials printed together. The proposed specimen geometries are manufactured without a variation of process parameters. The load types investigated in the course of this study were selected as examples and are tensile, lap-shear, and compression-shear. The conducted tests show that the proposed test specimens enable a quantification of the bonding quality in the material transition. Moreover, by analyzing the fracture pattern of the interface zone, influencing factors that probably affect the interface strength are identified, which can be further used for its optimization.
Hagen Watschke; Lennart Waalkes; Christian Schumacher; Thomas Vietor. Development of Novel Test Specimens for Characterization of Multi-Material Parts Manufactured by Material Extrusion. Applied Sciences 2018, 8, 1220 .
AMA StyleHagen Watschke, Lennart Waalkes, Christian Schumacher, Thomas Vietor. Development of Novel Test Specimens for Characterization of Multi-Material Parts Manufactured by Material Extrusion. Applied Sciences. 2018; 8 (8):1220.
Chicago/Turabian StyleHagen Watschke; Lennart Waalkes; Christian Schumacher; Thomas Vietor. 2018. "Development of Novel Test Specimens for Characterization of Multi-Material Parts Manufactured by Material Extrusion." Applied Sciences 8, no. 8: 1220.
Additive manufacturing (AM) allows the fabrication of complex design solutions and opens up new opportunities for improved products. To identify and optimally leverage these potentials, they must be considered as early as possible in new product development processes. Besides restrictive design rules, design for additive manufacturing (DFAM) thus particularly requires new opportunistic methods and tools in conceptual design and in the first steps of embodiment design. In this paper, AM design complexities and their benefits for new products are thoroughly analyzed and systematized. Many design methods from general design methodology can support the utilization of AM design potentials by their inherent nature of expanding the solution space. A criteria-based evaluation provides the basis for selecting and recommending appropriate design methods in the context of conceptual DFAM. To further adapt these methods to the identified AM design potentials, they are enriched by additional digital and physical DFAM tools. The combination of methods and tools is tested in a workshop environment with DFAM novices and DFAM experts to validate its practical applicability. It is shown that methodological support tailored to DFAM expertise and individual preferences can foster design potential utilization.
Martin Kumke; Hagen Watschke; Peter Hartogh; Ann-Kathrin Bavendiek; Thomas Vietor. Methods and tools for identifying and leveraging additive manufacturing design potentials. International Journal on Interactive Design and Manufacturing (IJIDeM) 2017, 12, 481 -493.
AMA StyleMartin Kumke, Hagen Watschke, Peter Hartogh, Ann-Kathrin Bavendiek, Thomas Vietor. Methods and tools for identifying and leveraging additive manufacturing design potentials. International Journal on Interactive Design and Manufacturing (IJIDeM). 2017; 12 (2):481-493.
Chicago/Turabian StyleMartin Kumke; Hagen Watschke; Peter Hartogh; Ann-Kathrin Bavendiek; Thomas Vietor. 2017. "Methods and tools for identifying and leveraging additive manufacturing design potentials." International Journal on Interactive Design and Manufacturing (IJIDeM) 12, no. 2: 481-493.
Additive manufacturing (AM) offers numerous benefits for innovative design solutions. However, engineers are currently not supported in identifying and incorporating these potentials systematically in their design solutions. In this paper, previous Design for Additive Manufacturing (DfAM) approaches are first reviewed comprehensively and classified into distinct categories according to their main purpose and application. They are then analysed further by being related to conventional design methodologies like VDI 2221. Since previous DfAM approaches only provide selective assistance at single steps in the product development process, a new framework for DfAM is proposed. Existing methods and tools, both from DfAM and from general design methodologies, are integrated into the modular framework structure. A concept for using the framework is presented to provide design engineers with continuous support in all product development phases, thereby fostering the complete exploitation of AM potentials and the development of AM-conformal designs.
Martin Kumke; Hagen Watschke; Thomas Vietor. A new methodological framework for design for additive manufacturing. Virtual and Physical Prototyping 2015, 11, 3 -19.
AMA StyleMartin Kumke, Hagen Watschke, Thomas Vietor. A new methodological framework for design for additive manufacturing. Virtual and Physical Prototyping. 2015; 11 (1):3-19.
Chicago/Turabian StyleMartin Kumke; Hagen Watschke; Thomas Vietor. 2015. "A new methodological framework for design for additive manufacturing." Virtual and Physical Prototyping 11, no. 1: 3-19.
Theodoros Tzivanopoulos; Hagen Watschke; Petia Krasteva; Thomas Vietor. New Approaches iIn Vehicle Conception. Auto Tech Review 2015, 4, 28 -33.
AMA StyleTheodoros Tzivanopoulos, Hagen Watschke, Petia Krasteva, Thomas Vietor. New Approaches iIn Vehicle Conception. Auto Tech Review. 2015; 4 (10):28-33.
Chicago/Turabian StyleTheodoros Tzivanopoulos; Hagen Watschke; Petia Krasteva; Thomas Vietor. 2015. "New Approaches iIn Vehicle Conception." Auto Tech Review 4, no. 10: 28-33.
Theodoros Tzivanopoulos; Hagen Watschke; Petia Krasteva; Thomas Vietor. New Approaches in Vehicle Conception. ATZ worldwide 2015, 117, 4 -9.
AMA StyleTheodoros Tzivanopoulos, Hagen Watschke, Petia Krasteva, Thomas Vietor. New Approaches in Vehicle Conception. ATZ worldwide. 2015; 117 (9):4-9.
Chicago/Turabian StyleTheodoros Tzivanopoulos; Hagen Watschke; Petia Krasteva; Thomas Vietor. 2015. "New Approaches in Vehicle Conception." ATZ worldwide 117, no. 9: 4-9.
Theodoros Tzivanopoulos; Hagen Watschke; Petia Krasteva; Thomas Vietor. Neue Denkansätze in der Fahrzeugkonzeption. ATZ - Automobiltechnische Zeitschrift 2015, 117, 16 -21.
AMA StyleTheodoros Tzivanopoulos, Hagen Watschke, Petia Krasteva, Thomas Vietor. Neue Denkansätze in der Fahrzeugkonzeption. ATZ - Automobiltechnische Zeitschrift. 2015; 117 (9):16-21.
Chicago/Turabian StyleTheodoros Tzivanopoulos; Hagen Watschke; Petia Krasteva; Thomas Vietor. 2015. "Neue Denkansätze in der Fahrzeugkonzeption." ATZ - Automobiltechnische Zeitschrift 117, no. 9: 16-21.