Fertigungstechnik

Fritz, Alfred Herbert

doi:10.1007/978-3-662-46555-4

Cited by 26 publications

(9 citation statements)

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“…A change in loading and deformation, which leads to lateral forces, causes irregular stresses within hinge elements, which continues in the transition zone between hinge and cell side. The stress distribution in cell sides is regular and can be adequately controlled according to equation (29), by dimensioning the cell side thickness of each cell for the maximum applicable pressure. Experiences with former demonstrators [16,17] and the subsequently presented implementation (see section 4) give rise to the assumption that an overload of a limited geometrical region does not endanger structural integrity.…”

Section: Discussion Of Deviationsmentioning

confidence: 99%

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Holistic design and implementation of pressure actuated cellular structures

Gramüller

Köke

Hühne

2015

Smart Mater. Struct.

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Providing the possibility to develop energy-efficient, lightweight adaptive components, Pressure-Actuated Cellular Structures (PACS) are primarily conceived for aeronautics applications. The realization of shape-variable flaps and even airfoils provides the potential to safe weight, increase aerodynamic efficiency and enhance agility. The herein presented holistic design process points out and describes the necessary steps for designing a real-life PACS structure, from the computation of truss geometry to the manufacturing and assembly. The already published methods for the form finding of PACS are adjusted and extended for the exemplary application of a variable-camber wing. The transfer of the form-finding truss model to a cross-sectional design is discussed. The end cap and sealing concept is described together with the implementation of the integral fluid flow. Conceptual limitations due to the manufacturing and assembly processes are discussed. The method's efficiency is evaluated by Finite Element Method (FEM). In order to verify the underlying methods and summarize the presented work a modular real-life demonstrator is experimentally characterized and validates the numerical investigations. [-] Reduction factor for seal design Figure 1: Venus flytrap, Dionaea muscipula (top left; photography by J. W. Webb); Microscope slide of Venus flytrap (top right; Copyright Carolina Biological Supply Company); Reproduction of the biological model by PACS (bottom) Various concepts for adaptive structures are inspired by this working principle. Ranzani et al. [3] developed a medical soft manipulator for minimally invasive surgery. Further soft robot concepts for gripping tools and robotic movement are realized by Ilievski et al. [4] and Guiducci et al. [5]. Zhang et al. [6], [7] theoretically investigate a three-dimensional approach that utilizes closed liquid cell materials for shape-changing structures. Two-dimensional approaches are examined by Lv et al. [8], [9] and Luo Q. et al. [10]. The concept of Pressure-Actuated Cellular Structures (PACS) differs from the above morphing structures as it bases on the optimization of discrete cell sides instead of the voids between them. It share most of their advantages with the pressure-adaptive honeycombs (PAH), which are extensively investigated by Vos et al. [11] and Barrett et al. [12] and patented in [13] and [14]. The idea of PACS utilizes the mechanisms of the Venus flytrap for technical use. It provides the possibility to specify arbitrary single-curved structures that deform stepless between predefined states of shape and allow to specifically manipulating its pressuredependent stiffness. First investigated theoretically by Pagitz et al. [15], a single row PACS demonstrator was subsequently realized by Gramüller et al. [16]. The lower depiction of Figure 1 shows the exemplary imitation of the Venus flytrap with a simplified illustration of a PACS with rigid cell sides and flexible hinges. One arm of this double row structure is realized in the ongoing work of Gramülle...

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Section: Discussion Of Deviationsmentioning

confidence: 99%

“…Evaluation of manufacturing processes for cell compound according to underlying demand analysis; (SLM: Selective laser melting; SLA: Stereolithography; FDM: Fused deposition modeling; EDM: Electrical discharge machining)[29,30].…”

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confidence: 99%

Holistic design and implementation of pressure actuated cellular structures

Gramüller

Köke

Hühne

2015

Smart Mater. Struct.

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“… The main cause for the step-shaped inner surface of the punch-outs may most likely be a wrong dimensioned clearance [11]. This still has to be proven using a test tool and by the variation of the clearance (chapter 3.3).…”

Section: Hypotheses and Approaches On Burr And Film Formationmentioning

confidence: 99%

Process development for punching extruded PC based materials in cable duct production

2019

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Burr and film formation occurring when punching polycarbonate/ acrylonitrile butadiene styrene (PC/ABS) cable ducts is a common problem during manufacturing of cable ducts. However, little knowledge on base materials, their thermal and mechanical behavior as well as their initial processing and finally behavior during cable duct manufacturing is available. Therefore, to improve process reliability and gain knowledge on mechanical and failure behavior necessary initial investigations focus on cable duct usage, different geometric types, polymer materials and the punching process itself. Optical analysis on punched PC/ABS cable duct with burr and film formation and corresponding punch led to definition of the test tool’s geometry for subsequent tests. Since the punching process directly influences burr and film formation, it was necessary to design a demo-tool to observe the burr and film origin. Tensile tests at different test speeds focus on in-situ mechanical behavior using coupons taken from industrial cable ducts made of mineral reinforced polycarbonate (PC) and PC/ABS including further additives that are generally used in industry. First results indicate that higher test speeds appear to reduce the influence of the different admixtures on the elongation behavior of PC based materials.

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“…Per definition, AM stands for series production using generative processes [1]. Due to the capability to build up parts, layer by layer, directly from 3D data, every part can be optimized to its individual task.…”

Section: Introductionmentioning

confidence: 99%

Wire-based additive manufacturing using an electron beam as heat source

Fuchs¹,

Schneider²,

Enzinger³

2018

Weld World

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Many standard welding processes, such as gas metal arc-, laser-, or electron-beam welding, can be used for additive manufacturing (AM) with only slight adaptions. Wire-based additive manufacturing provides an interesting alternative to powder-based processes due to their simplicity and comparatively high deposition rates. The use of an electron beam as heat source for AM offers unique possibilities for construction of components due to its inherent flexibility. It is possible to efficiently build bigger parts with comparably fine features and high complexity. Furthermore, additional working steps such as preheating, surface modification, welding, or heat treatments can be implemented into the additive manufacturing process and thereby alleviate the bottleneck of the evacuation of the vacuum chamber. Aside from this, the ultra high vacuum atmosphere can be beneficial, when working with reactive materials such as Ti or Mo. The intrinsic complexity of electron-beam additive manufacturing (EBAM) can make a stable and reproducible process control quite challenging. In this study, the influence of the main process parameters, such as heat input, energy distribution, wire feed, and their complex interactions are investigated. Based on single beads on a mild steel substrate using an unalloyed metal core wire (G4Si1), the correlation between the process parameters such as beam current, acceleration voltage, speed, wire feed rate and position, and the resulting bead geometry, height, width and penetration was studied. These findings were used to successfully establish a multi pass layout consisting of one to six beads next to each other and up to ten layers in height. For basic characterization, metallographic analysis as well as hardness measurements were performed.

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Fertigungstechnik

Abstract: Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.d-nb.de abrufbar.

Cited by 26 publications

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Holistic design and implementation of pressure actuated cellular structures

Holistic design and implementation of pressure actuated cellular structures

Process development for punching extruded PC based materials in cable duct production

Wire-based additive manufacturing using an electron beam as heat source

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