2024-03-29T10:50:33Z
https://serwiss.bib.hs-hannover.de/oai
oai:serwiss.opus4:38
2022-02-17
doc-type:book
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:true
Qualitätsbestimmende Einflußgrößen bei Kunststoff-Metall-Klebverbindungen
Rasche, Manfred
Qualität
Einfluss
Kunststoff
Klebeverbindung
ddc:670
Das Buch behandelt verschiedene Klebtechniken.
Hannover : Hochschule Hannover
1986
book
doc-type:book
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/38
urn:nbn:de:bsz:960-opus-722
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus-722
3-87155-864-8
https://doi.org/10.25968/opus-38
https://serwiss.bib.hs-hannover.de/files/38/rasche_qualitaetsbestimmende_einflussgroessen_kunststoff_metall_klebverbindungen_1986a.pdf
deu
https://rightsstatements.org/page/InC/1.0/
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:1141
2021-03-19
doc-type:bachelorThesis
bibliography:false
ddc
ddc:670
ddc:004
open_access
open_access:open_access
has-source-swb
has-source-swb:true
Entwicklung einer mobilen Anwendung zur Produktnachverfolgung im Fertigungsprozess
Sperling, Marvin
App <Programm>
Softwareentwicklung
Fertigung
ddc:670
ddc:004
Die Digitalisierung birgt sowohl für den Unternehmer, als auch für den Kunden diverse Vorteile. Als Instrument zur Veranschaulichung dieser Vorteile dienen vor allem Service-Apps, welche bereits von großen Unternehmen beispielsweise zur Produktnachverfolgung etabliert wurden. Das Mittelstand 4.0 – Kompetenzzentrum Hannover legt den Fokus auf kleine und mittelständische Produktionsbetriebe und vermittelt das Potenzial der Digitalisierung im Rahmen von Industrie 4.0. Dies geschieht anhand einer Produktionslinie personalisierter Kugelschreiber und einer zu Demonstrationszwecken entwickelten App für mobile Endgeräte. Konzeptionierung, Entwicklung und Umsetzung dieser App werden genauestens aufgeführt und erläutert. Die App wurde unter dem Betriebssystem Android entwickelt und gliedert sich in sieben Phasen, beginnend mit der Anforderungsanalyse bis hin zur Veröffentlichung im Google Play Store. Während der Unternehmer die Möglichkeit geboten bekommt, Rückschlüsse als Entscheidungshilfe zur effizienteren Gestaltung der Produktion zu nutzen, ist der Kunde in der Lage, seine Aufträge echtzeitnah in der Produktion nachzuverfolgen und gegebenenfalls Änderungen vorzunehmen.
Hannover : Hochschule Hannover
Institut für Fertigungstechnik und Werkzeugmaschinen (IFW) der Universität Hannover
2017
bachelorthesis
doc-type:bachelorThesis
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/1141
urn:nbn:de:bsz:960-opus4-11414
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-11414
https://doi.org/10.25968/opus-1141
https://serwiss.bib.hs-hannover.de/files/1141/BA_Ver%C3%B6ffentlichung_Sperling.pdf
deu
https://creativecommons.org/licenses/by-nc/4.0/deed.de
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:2369
2023-03-31
doc-type:article
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:true
Continuous Fiber-Reinforced Material Extrusion with Hybrid Composites of Carbon and Aramid Fibers
Heitkamp, Tim
Girnth, Simon
Kuschmitz, Sebastian
Klawitter, Günter (Prof. Dr.-Ing.)
Waldt, Nils (Prof. Dr.-Ing.)
Vietor, Thomas (Prof. Dr.-Ing.)
Extrudieren
ddc:670
An existing challenge in the use of continuous fiber reinforcements in additively manufactured parts is the limited availability of suitable fiber materials. This leads to a reduced adaptability of the mechanical properties to the load case. The increased design freedom of additive manufacturing allows the flexible deposition of fiber strands at defined positions, so that even different fiber materials can be easily combined in a printed part. In this work, therefore, an approach is taken to combine carbon and aramid fibers in printed composite parts to investigate their effects on mechanical properties. For this purpose, tensile, flexural and impact tests were performed on printed composite parts made of carbon and aramid fibers in a nylon matrix with five different mixing ratios. The tests showed that the use of hybrid composites for additive manufacturing is a reasonable approach to adapt the mechanical properties to the loading case at hand. The experiments showed that increasing the aramid fiber content resulted in an increase in impact strength, but a decrease in tensile and flexural strength and a decrease in stiffness. Microstructural investigations of the fracture surfaces showed that debonding and delamination were the main failure mechanisms. Finally, Rule of Hybrid Mixture equations were applied to predict the mechanical properties at different mixture ratios. This resulted in predicted values that differed from the experimentally determined values by an average of 5.6%.
MDPI
Hannover : Hochschule Hannover
2022
article
doc-type:article
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/2369
urn:nbn:de:bsz:960-opus4-23699
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-23699
https://doi.org/10.25968/opus-2369
https://serwiss.bib.hs-hannover.de/files/2369/heitkamp_etal2022-material_extrusion.pdf
eng
https://creativecommons.org/licenses/by/4.0/deed.de
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:2398
2023-03-02
doc-type:article
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:true
Direction dependency in coaxial laser double wire Direct Energy Deposition
Schwarz, Nick
Lammers, Marius
Hermsdorf, Jörg (Dr.-Ing.)
Kaierle, Stefan
Ahlers, Henning (Prof. Dr.-Ing.)
Lachmayer, Roland
Funktioneller Gradientenwerkstoff
Direct Energy Deposition
Schweißdraht
Laser
ddc:670
Coaxial Laser wire Direct Energy Deposition (L-DED) promises a direction-independent buildup due to a centric supply of the welding material. To fabricate Functionally Graded Materials (FGMs), a processing head was designed that is capable of supplying two wire materials into the processing zone. This study investigates the direction dependency of welding seams produced by two 1.4718 metal wires with a diameter of 0.8 mm in a coaxial laser setup using three separately controllable single laser beams with a maximum combined laser power of 660 W. The welding wires are supplied simultaneously to the laser spot under an incidence angle of 3.5° to the middle axis of the processing head. The seam geometry is investigated using a confocal laserscanning-microscope. A comparison of the height, width and macroscopic seam geometry reveals the influence of the welding direction on the seam geometry and quality in Laser Double wire Direct Energy Deposition (LD-DED).
Hannover : Hochschule Hannover
2022
article
doc-type:article
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/2398
urn:nbn:de:bsz:960-opus4-23980
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-23980
https://doi.org/10.25968/opus-2398
https://serwiss.bib.hs-hannover.de/files/2398/schwarz_etal2022-laser_double_wire.pdf
eng
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:2406
2024-02-26
doc-type:article
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:true
Stress-adapted fiber orientation along the principal stress directions for continuous fiber-reinforced material extrusion
Heitkamp, Tim
Kuschmitz, Sebastian
Girnth, Simon
Marx, Justin-Dean
Klawitter, Günter (Prof. Dr.-Ing.)
Waldt, Nils
Vietor, Thomas (Prof. Dr.-Ing.)
Extrudieren
ddc:670
A proven method to enhance the mechanical properties of additively manufactured plastic parts is the embedding of continuous fibers. Due to its great flexibility, continuous fiber-reinforced material extrusion allows fiber strands to be deposited along optimized paths. Nevertheless, the fibers have so far been embedded in the parts contour-based or on the basis of regular patterns. The outstanding strength and stiffness properties of the fibers in the longitudinal direction cannot be optimally utilized. Therefore, a method is proposed which allows to embed fibers along the principal stresses into the parts in a load-oriented manner. A G-code is generated from the calculated principal stress trajectories and the part geometry, which also takes into account the specific restrictions of the manufacturing technology used. A distinction is made between fiber paths and the matrix so that the average fiber volume content can be set in a defined way. To determine the mechanical properties, tensile and flexural tests are carried out on specimens consisting of carbon fiber-reinforced polyamide. In order to increase the influence of the principal stress-based fiber orientation, open-hole plates are used for the tensile tests, as this leads to variable stresses across the cross section. In addition, a digital image correlation system is used to determine the deformations during the mechanical tests. It was found that the peak load of the optimized open-hole plates was greater by a factor of 3 and the optimized flexural specimens by a factor of 1.9 than the comparison specimens with unidirectional fiber alignment.
Hannover : Hochschule Hannover
2022
article
doc-type:article
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/2406
urn:nbn:de:bsz:960-opus4-24064
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-24064
https://doi.org/10.25968/opus-2406
https://serwiss.bib.hs-hannover.de/files/2406/heitkamp_etal_2022-fiber_orientation.pdf
eng
https://creativecommons.org/licenses/by/4.0/deed.de
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:2470
2024-02-26
doc-type:article
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:true
Experimental and Numerical Investigation of the Mechanical Properties of 3D-Printed Hybrid and Non-Hybrid Composites
Heitkamp, Tim
Girnth, Simon
Kuschmitz, Sebastian
Waldt, Nils
Klawitter, Günter
Vietor, Thomas
Extrudieren
ddc:670
Recent research efforts have highlighted the potential of hybrid composites in the context of additive manufacturing. The use of hybrid composites can lead to an enhanced adaptability of the mechanical properties to the specific loading case. Furthermore, the hybridization of multiple fiber materials can result in positive hybrid effects such as increased stiffness or strength. In contrast to the literature, where only the interply and intrayarn approach has been experimentally validated, this study presents a new intraply approach, which is experimentally and numerically investigated. Three different types of tensile specimens were tested. The non-hybrid tensile specimens were reinforced with contour-based fiber strands of carbon and glass. In addition, hybrid tensile specimens were manufactured using an intraply approach with alternating carbon and glass fiber strands in a layer plane. In addition to experimental testing, a finite element model was developed to better understand the failure modes of the hybrid and non-hybrid specimens. The failure was estimated using the Hashin and Tsai–Wu failure criteria. The specimens showed similar strengths but greatly different stiffnesses based on the experimental results. The hybrid specimens demonstrated a significant positive hybrid effect in terms of stiffness. Using FEA, the failure load and fracture locations of the specimens were determined with good accuracy. Microstructural investigations of the fracture surfaces showed notable evidence of delamination between the different fiber strands of the hybrid specimens. In addition to delamination, strong debonding was particularly evident in all specimen types.
MDPI
Hannover : Hochschule Hannover
2023
article
doc-type:article
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/2470
urn:nbn:de:bsz:960-opus4-24703
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-24703
https://doi.org/10.25968/opus-2470
https://serwiss.bib.hs-hannover.de/files/2470/heitkamp_etal2023-3d-printed-composites.pdf
eng
https://creativecommons.org/licenses/by/4.0/deed.de
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:3045
2024-02-26
doc-type:article
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:false
Parametric study of piezoresistive structures in continuous fiber reinforced additive manufacturing
Heitkamp, Tim
Goutier, Marijn
Hilbig, Karl
Girnth, Simon
Waldt, Nils
Klawitter, Günter (Prof. Dr.)
Vietor, Thomas
Faser
3D-Druck
Resistiver Sensor
Extrudieren
Halbleiterdrucksensor
Kohlenstofffaser
ddc:670
Recent advancements in fiber reinforced additive manufacturing leverage the piezoresistivity of continuous carbon fibers. This effect enables the fabrication of structural components with inherent piezoresistive properties suitable for load measurement or structural monitoring. These are achieved without necessitating additional manufacturing or assembly procedures. However, there remain unexplored variables within the domain of continuous fiber-reinforced additive manufacturing. Crucially, the roles of fiber curvature radii and sensing fiber bundle counts have yet to be comprehensively addressed. Additionally, the compression-sensitive nature of printed carbon fiber-reinforced specimens remains a largely unexplored research area. To address these gaps, this study presents experimental analyses on tensile and three-point flexural specimens incorporating sensing carbon fiber strands. All specimens were fabricated with three distinct curvature radii. For the tensile specimens, the number of layers was also varied. Sensing fiber bundles were embedded on both tensile and compression sides of the flexural specimens. Mechanical testing revealed a linear-elastic behavior in the specimens. It was observed that carbon fibers supported the majority of the load, leading to brittle fractures. The resistance measurements showed a dependence on both the number of sensing layers and the radius of curvature, and exhibited a slight decreasing trend in the cyclic tests. Compared with the sensors subjected to tensile stress, the sensors embedded on the compression side showed a lower gauge factor.
Hannover : Hochschule Hannover
2024
article
doc-type:article
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/3045
urn:nbn:de:bsz:960-opus4-30456
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-30456
https://doi.org/10.25968/opus-3045
https://serwiss.bib.hs-hannover.de/files/3045/heitkamp_etal2024-piezoresistive_struct_manu.pdf
eng
https://creativecommons.org/licenses/by/4.0/deed.de
info:eu-repo/semantics/openAccess
oai:serwiss.opus4:3046
2024-02-26
doc-type:article
bibliography:false
ddc
ddc:670
open_access
open_access:open_access
has-source-swb
has-source-swb:false
Dimensionless quantities in discrete element method: powder model parameterization for additive manufacturing
Girnth, Simon
Heitkamp, Tim
Wacker, Christian
Waldt, Nils
Klawitter, Günter (Prof. Dr.)
Dröder, Klaus
Fertigungstechnik
Selektives Laserschmelzen
Rapid Prototyping <Fertigung>
Diskrete-Elemente-Methode
ddc:670
Powder bed-based additive manufacturing processes offer an extended freedom in design and enable the processing of metals, ceramics, and polymers with a high level of relative density. The latter is a prevalent measure of process and component quality, which depends on various input variables. A key point in this context is the condition of powder beds. To enhance comprehension of their particle-level formation and facilitate process optimization, simulations based on the Discrete Element Method are increasingly employed in research. To generate qualitatively as well as quantitatively reliable simulation results, an adaptation of the contact model parameterization is necessary. However, current adaptation methods often require the implementation of models that significantly increase computational effort, therefore limiting their applicability. To counteract this obstacle, a sophisticated formula-based adaptation and evaluation method is presented in this research. Additionally, the developed method enables accelerated parameter determination with limited experimental effort. Thus, it represents an integrative component, which supports further research efforts based on the Discrete Element Method by significantly reducing the parameterization effort. The universal nature of deducting this method also allows its adaptation to similar parameterization problems and its implementation in other fields of research.
Hannover : Hochschule Hannover
2024
article
doc-type:article
application/pdf
https://serwiss.bib.hs-hannover.de/frontdoor/index/index/docId/3046
urn:nbn:de:bsz:960-opus4-30461
https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-30461
https://doi.org/10.25968/opus-3046
https://serwiss.bib.hs-hannover.de/files/3046/girnth_etal2024-dimensionless_quantities.pdf
eng
https://creativecommons.org/licenses/by/4.0/deed.de
info:eu-repo/semantics/openAccess