scholarly journals Simulation Assisted Process Development for Tailored Forming

2019 ◽  
Vol 949 ◽  
pp. 101-111 ◽  
Author(s):  
Bernd Arno Behrens ◽  
Martin Bonhage ◽  
Dieter Bohr ◽  
Deniz Duran
Keyword(s):  
Collaborative Research ◽  
Elevated Temperatures ◽  
Process Development ◽  
Research Centre ◽  
Process Chains ◽  
Technological Developments ◽  
Deformation Processes ◽  
Production Technologies ◽  
Fuel Costs ◽  
Tailored Forming

Transport industry faces challenges steadily due to rising fuel costs and stricter regulations for the emission of air pollutants. Technological developments that reduce fuel consumption are necessary for sustainable and resource-efficient transport. Innovative production technologies utilising multi-material designs come to the fore in an attempt to fabricate lightweight products with extended functionality. Departing from this motivation, novel process chain concepts for the manufacturing of bi-material forged products are being researched at the Leibniz Universität Hannover in the context of the Collaborative Research Centre (CRC) 1153. The developed technology is referred as Tailored Forming and deals with the deformation and subsequent processing of joined hybrid workpieces to produce application-oriented products. Deformation processes are carried out at elevated temperatures for thermomechanical treatment of the joining zone properties. Researchers make use of numerical simulation in each step in the process chains. This paper explains the challenges associated with induction heating and impact extrusion of bi-material forging billets and presents our solution approaches with the aid of numerical modelling. Experimental validation results and analysis of deformed workpieces are also shown.

scholarly journals Introduction to tailored forming

2021 ◽  
Author(s):  
B.-A. Behrens ◽  
J. Uhe
Keyword(s):  
Collaborative Research ◽  
Lightweight Design ◽  
Production Quality ◽  
Research Centre ◽  
Lightweight Construction ◽  
Forming Process ◽  
Process Chains ◽  
Finishing Processes ◽  
Tailored Forming ◽  
Joining Process

AbstractIn recent years, the requirements for technical components have been increasing steadily. This development is intensified by the desire for products with lower weight, smaller size and extended functionality, but at the same time higher resistance against specific loads. Mono-material components manufactured according to established processes reach their limits regarding conflicting requirements. It is, for example, hardly possible to combine excellent mechanical properties with lightweight construction using mono-materials. Thus, a significant increase in production quality, lightweight design, functionality and efficiency can only be reached by combining different materials in one component. The superior aim of the Collaborative Research Centre (CRC) 1153 is to develop novel process chains for the production of hybrid solid components. In contrast to existing process chains in bulk metal forming, in which the joining process takes place during forming or at the end of the process chain, the CRC 1153 uses tailored semi-finished workpieces which are joined before the forming process. This results in a geometric and thermomechanical influence on the joining zone during the forming process which cannot be created by conventional joining techniques. The present work gives an overview of the CRC and the Tailored Forming approach including the applied joining, forming and finishing processes as well as a short summary of the accompanying design and evaluation methods.

An Approach to Classify Methods to Control Uncertainty in Load-Carrying Structures

2011 ◽  
Vol 104 ◽  
pp. 33-44 ◽  
Author(s):  
Roland Engelhardt ◽  
Jan F. Koenen ◽  
Matthias Brenneis ◽  
Hermann Kloberdanz ◽  
Andrea Bohn
Keyword(s):  
Present Article ◽  
Collaborative Research ◽  
Mechanical Engineering ◽  
Process Development ◽  
Holistic Approach ◽  
Research Centre ◽  
Load Carrying ◽  
Product And Process

Today, a wide variety of methods to deal with uncertainty in load-carrying system exists. Thereby, uncertainty may result from not or only partially determined process properties. The present article proposes a classification of methods to control uncertainty in load-carrying systems from different disciplines within mechanical engineering. Therefore, several methods were collected, analysed and systematically classified concerning their characteristic into the proposed classification. First, the classification differs between degrees of uncertainty according to the model of uncertainty developed in the Collaborative Research Centre CRC 805. Second, the classification differs between the aim of the respective method to descriptive methods, evaluative methods or methods to design a system considering uncertainty. The classification should allow choosing appropriate methods during product and process development and thus to control uncertainty in a systematic and holistic approach.

Microstructuring by a Combination of Micro Impact Extrusion and Shear Displacement Forming

2013 ◽  
Vol 554-557 ◽  
pp. 893-899 ◽  
Author(s):  
Andreas Schubert ◽  
Stephan F. Jahn ◽  
Benedikt Müller
Keyword(s):  
Cross Sections ◽  
Material Flow ◽  
Extrusion Process ◽  
Shear Displacement ◽  
Raw Material ◽  
Hybrid Process ◽  
Research Centre ◽  
Forming Process ◽  
Process Chains ◽  
Production Technologies

The Collaborative Research Centre SFB/TR 39 PT-PIESA is developing mass production technologies and process chains for the fabrication of aluminium piezo composites, which can be used as raw material for "smart sheet metal" [1]. Microstructuring by forming is a challenging task concerning material flow, tool and process design [2]. In this study, a hybrid forming process combined of micro impact extrusion and shear displacement is presented and discussed. The formed microstructure, depicted in figure 1, consists of ten parallel primary cavities with cross sections of 0.3×0.3 mm² and four larger secondary cavities which are surrounding the primary cavities. High demands are made concerning precision and reproducibility of the cavities' geometry according to the function of the cavities, which is to serve as collets for sensitive piezo rods. The microstructure has to be formed with one stroke of the stamp. Micro backward impact extrusion is chosen for structuring the primary cavities since it allows accurate forming without aligning die plate and stamp due to a flat die plate. Shear displacement forming, which is the selected process for the secondary cavities, requires a structured and aligned die plate but the forming forces are significantly lower than forming the same geometry with an extrusion process which in turn increases the accuracy. The investigations are focused on the characterization of samples formed with the hybrid process in comparison to structures which are formed solely by impact extrusion. Geometric parameters, material flow and process parameters were evaluated to assess the hybrid process. First experiments show promising results, whereas higher degrees of deformation could be reached at lower forming forces. Exemplary, sections for both processes are depicted in figure 2.

Das intelligente Instandhaltungssystem/The intelligent maintenance system - An approach for the self-learning structuring of maintenance libraries

2017 ◽  
Vol 107 (07-08) ◽  
pp. 530-535
Author(s):  
T. Miebach ◽  
M. Schmidt ◽  
P. Prof. Nyhuis
Keyword(s):  
Collaborative Research ◽  
The Self ◽  
Research Centre ◽  
Maintenance System ◽  
Intelligent Maintenance ◽  
Product Engineering ◽  
The Right ◽  
Self Learning ◽  
Intelligent Maintenance System

Der Fachbeitrag stellt eine Methode vor, mit der sich Bibliotheken von Instandhaltungsmaßnahmen selbstlernend gestalten lassen. Die „Intelligenz“ solcher Systeme bietet mehrfachen Nutzen, einerseits durch die Auswahl der passenden Instandhaltungsmethode zum richtigen Zeitpunkt, andererseits durch die damit verbundene Erhöhung des kompletten Abnutzungsvorrates. Die Ergebnisse sind im Sonderforschungsbereich 653 „Gentelligente Bauteile im Lebenszyklus – Nutzung vererbbarer, bauteilinhärenter Informationen in der Produktionstechnik“ entstanden.   This article describes a method to design a self-learning maintenance library. The benefit derived from the intelligence of those systems refers to the right choice of maintenance measures at the right time and the enhancement of the whole wear margin. The results are part of the Collaborative Research Centre 653: Gentelligent components in their lifecycle – Utilization of inheritable component information in product engineering.

scholarly journals Resilience in Mechanical Engineering - A Concept for Controlling Uncertainty during Design, Production and Usage Phase of Load-Carrying Structures

2018 ◽  
Vol 885 ◽  
pp. 187-198 ◽  
Author(s):  
Lena C. Altherr ◽  
Nicolas Brötz ◽  
Ingo Dietrich ◽  
Tristan Gally ◽  
Felix Geßner ◽  
...  
Keyword(s):  
Collaborative Research ◽  
Mechanical Engineering ◽  
Research Centre ◽  
Product Life ◽  
Usage Phase ◽  
Load Carrying ◽  
Design Production ◽  
Technical Systems

Resilience as a concept has found its way into different disciplines to describe the ability of an individual or system to withstand and adapt to changes in its environment. In this paper, we provide an overview of the concept in different communities and extend it to the area of mechanical engineering. Furthermore, we present metrics to measure resilience in technical systems and illustrate them by applying them to load-carrying structures. By giving application examples from the Collaborative Research Centre (CRC) 805, we show how the concept of resilience can be used to control uncertainty during different stages of product life.

scholarly journals ANALYSIS OF DEFORMATION PROCESSES OF MAGNESIUM ALLOY AT ELEVATED TEMPERATURES BY ORIENTATION MAPPING

2011 ◽  
Vol 23 (1) ◽  
pp. 53 ◽  
Author(s):  
Ping Yang ◽  
Li Meng ◽  
Yisong Hu ◽  
Zude Zhao ◽  
Xueping Ren
Keyword(s):  
Magnesium Alloy ◽  
Elevated Temperatures ◽  
Plastic Slip ◽  
Rotation Axes ◽  
Orientation Mapping ◽  
Back Scattering ◽  
Deformation Processes ◽  
Relationship Of ◽  
The Relationship

Orientation mapping based on electron back scattering diffraction technique was applied to reveal the distributions of disorientations and rotation axes of grains caused by plastic slip and twinning during channel die compression in magnesium alloy ZA31. In addition, the orientations of dynamically recrystallized grains and deformed grains were separated and compared with respect to their initial textures. The relationship of strain and {1012} twin amount was determined quantitatively by referring to twin orientations. The reasons leading to the observed phenomena are analyzed and discussed.

scholarly journals The concept of socio-environmental transformations in prehistoric and archaic societies in the Holocene: An introduction to the special issue

The Holocene ◽  
2019 ◽  
Vol 29 (10) ◽  
pp. 1517-1530 ◽  
Author(s):  
Johannes Müller ◽  
Wiebke Kirleis
Keyword(s):  
Collaborative Research ◽  
Spatial Scales ◽  
Environmental Research ◽  
Research Centre ◽  
Detailed Data ◽  
Special Issue ◽  
The Holocene ◽  
Archaeological Methods ◽  
Temporal And Spatial

Transformations of human societies and environments are closely interwoven. Due to improved possibilities of paleoecological reconstruction and archaeological methods, we are now in a position to empirically collect detailed data from a variety of records. The Collaborative Research Centre 1266 ‘Scales of Transformation’ has developed a concept in which both deductive and inductive transformation dimensions are compared on different temporal and spatial scales. This concept includes the connection between the environmental and social spheres, which are often inseparable. Accordingly, a holistic principle of socio-environmental research is developed, which is exemplified by the contributions to this special issue of The Holocene.

scholarly journals Manufacturing and Evaluation of Multi-Material Axial-Bearing Washers by Tailored Forming

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 232 ◽  
Author(s):  
Bernd-Arno Behrens ◽  
Alexander Chugreev ◽  
Tim Matthias ◽  
Gerhard Poll ◽  
Florian Pape ◽  
...  
Keyword(s):  
Layer Structure ◽  
Roller Bearing ◽  
Welding Process ◽  
Rolling Contact ◽  
Acoustic Microscopy ◽  
Research Centre ◽  
Forming Process ◽  
Rolling Bearings ◽  
Cylindrical Roller ◽  
Tailored Forming

Components subject to rolling contact fatigue, such as gears and rolling bearings, are among the fundamental machine elements in mechanical and vehicle engineering. Rolling bearings are generally not designed to be fatigue-resistant, as the necessary oversizing is not technically and economically marketable. In order to improve the load-bearing capacity, resource efficiency and application possibilities of rolling bearings and other possible multi-material solid components, a new process chain was developed at Leibniz University Hannover as a part of the Collaborative Research Centre 1153 “Tailored Forming”. Semi-finished products, already joined before the forming process, are used here to allow a further optimisation of joint quality by forming and finishing. In this paper, a plasma-powder-deposition welding process is presented, which enables precise material deposition and control of the welding depth. For this study, bearing washers (serving as rolling bearing raceways) of a cylindrical roller thrust bearing, similar to type 81212 with a multi-layer structure, were manufactured. A previously non-weldable high-performance material, steel AISI 5140, was used as the cladding layer. Depending on the degree of forming, grain-refinement within the welded material was achieved by thermo-mechanical treatment of the joining zone during the forming process. This grain-refinements lead to an improvement of the mechanical properties and thus, to a higher lifetime for washers of an axial cylindrical roller bearing, which were examined as an exemplary component on a fatigue test bench. To evaluate the bearing washers, the results of the bearing tests were compared with industrial bearings and deposition welded axial-bearing washers without subsequent forming. In addition, the bearing washers were analysed micro-tribologically and by scanning acoustic microscopy both after welding and after the forming process. Nano-scratch tests were carried out on the bearing washers to analyse the layer properties. Together with the results of additional microscopic images of the surface and cross-sections, the causes of failure due to fatigue and wear were identified.

Process Development of Silicon-Silicon Carbide Hybrid Micro-Engine Structures

2001 ◽  
Vol 687 ◽  
Author(s):  
Dongwon Choi ◽  
Robert J. Shinavski ◽  
Wayne S. Steffier ◽  
Skip Hoyt ◽  
S.Mark Spearing
Keyword(s):  
Silicon Carbide ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Process Development ◽  
High Stress ◽  
Development Program ◽  
High Strength ◽  
Operating Conditions ◽  
Source Power ◽  
Silicon Silicon

AbstractA MEMS-based gas turbine engine is being developed for use as a button-sized portable power generator or micro-aircraft propulsion source. Power densities expected for the micro- engine require high combustor exit temperatures (1300-1700K) and very high rotor peripheral speeds (300-600m/s). These harsh operating conditions induce high stress levels in the engine structure, and thus require refractory materials with high strength. Silicon carbide has been chosen as the most promising material for use in the near future due to its high strength and chemical inertness at elevated temperatures. However, techniques for microfabricating single- crystal silicon carbide to the level of high precision needed for the micro-engine are not currently available. To circumvent this limitation and to take advantage of the well-established precise silicon microfabrication technologies, silicon-silicon carbide (SiC) hybrid turbine structures are being developed using chemical vapor deposition of poly-SiC on silicon wafers and wafer bonding processes. Residual stress control of SiC coatings is of critical importance to all the silicon-silicon carbide hybrid structure fabrication steps since a high level of residual stresses causes wafer cracking during the planarization, as well as excessive wafer bow, which is detrimental to the subsequent planarization and bonding processes. The origins of the residual stresses in CVD SiC layers have been studied. SiC layers (as thick as 30µm) with low residual stresses (on the order of several tens of MPa) have been produced by controlling CVD process parameters such as temperature and gas ratio. Wafer-level SiC planarization has been accomplished by mechanical polishing using diamond grit and bonding processes are currently under development using interlayer materials such as silicon dioxide or poly-silicon. These process development efforts will be reviewed in the context of the overall micro-engine development program.

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