检索结果-内蒙古大学图书馆

Experimental Study on Micro forming of Structured Surfaces for High Static Friction Connection Elements

Procedia Manufacturing 2020年 47卷 1230-1234页

作者： Ingo Schaarschmidt Philipp Steinert Matthias Hackert-Oschätzchen Gunnar Meichsner Andreas Schubert Guido Jungblut Professorship Micromanufacturing Technology Faculty of Mechanical Engineering Chemnitz University of Technology 09107 Chemnitz Germany Chair of Manufacturing Technology with Focus Machining Otto von Guericke University Magdeburg 39106 Magdeburg Germany Fraunhofer Institute for Machine Tools and Forming Technology 09126 Chemnitz Germany Pro-Com A. Jungblut GmbH 66663 Merzig Germany

Bolt connections are the most prevalent technical solution to join several devices. To meet high requirements on lightweight constructions and safety-relevant technologies bolt connections require additional security elements or surface modifications to increase static friction without damaging the workpiece surface significantly. One possible solution is the micro structuring of the connection element surface within the conventional forming process chain. For the manufacturing of micro structured connection elements a micro structured forming tool is needed. Therefore, the forming tool has to feature a negative geometry of the connection element surface micro geometry. Requirements on forming tool materials are high hardness in combination with high wear resistance and good toughness. Suitable technologies to manufacture such micro structured metal dies are laser beam machining (LBM), electrochemical machining (ECM) and electrical discharge machining (EDM), respectively. In this study the micro forming process of high static friction connection elements is investigated. The manufactured connection element surfaces are analyzed after the forming experiments and the results are associated with the surfaces of the metal dies. Therefore the surfaces of the utilized metals dies are compared with each other and with a grinded reference surface and characteristic parameters are analyzed. The comparison is based on the resulting surface roughness parameters and surface conditions before and after lubricated forming experiments. At least wear of the metal dies after multiple forming operations is analyzed. As one result, ECM manufactured metal dies have shown a high degree of replication in combination with high wear resistance.

关键词： Micro forming Static friction Connection element

来源：评论

学校读者我要写书评

暂无评论

Mathematical Model of One and Two-Step Methods Calculation of Thermal Fields and Stress-Strain State of Multilayer Cylindrical Constructions

引用

Materials Today: Proceedings 2019年 11卷 494-503页

作者： Denis Elovenko Andreas Hirsch Verena Kräusel Department of Design and Standardization in Mechanical Engineering Irkutsk National Research Technical University 83 Lermontov street 664074 Irkutsk Russian Federation Professorship Machine Tools and Forming Technology Technische Universität Chemnitz Reichenhainer Str. 70 09107 Chemnitz Germany Professorship Forming and Joining Technische Universität Chemnitz Reichenhainer Str. 70 09107 Chemnitz Germany

Two-step and one-step methods for calculating thermal fields and stress-strain state of multilayer cylindrical constructions (parts of vessel bodies or reactors) have been developed to ensure their functioning under the conditions of high internal pressure and temperature. The efficiency of this algorithms by a simple example of the contact interaction of two cylinders of equal rigidity (α = 0,5) and thermal conductivity in two cylinders in contact heat exchange with thermal conductivity of similar value (α = 0,5) are shown. Two-step method implements the alternate solution step by step of applying kinematic and force tasks for solving the problem of static contact and the tasks of heat transfer and heat field for solving the thermal problem. One-step method realizes the solution of either the power problem on basis of the determined the error resulting from the addressing the kinematic problem, as it is determined in the previous step, or the kinematic problem on the basis of the specified error stemming from the addressing the force problem, which is also defined in the previous step for solve the static contact problem. Also, one-step method realizes the solution applied to the heat transfer problem based on the specified value of the error deriving from the initial addressing the said problem which is determined in the previous step.

关键词： stress state numeral method autoclave stress contact iteration

来源：评论

学校读者我要写书评

暂无评论

Methodology for the early analysis and evaluation of the resource efficiency of process chains for manufacturing hybrid structures

引用

Procedia Manufacturing 2019年 33卷 430-437页

作者： C. Symmank J. Boll A. Rautenstrauch A. Graf L. Markov R. Decker A. Schmidt U. Götze B. Awiszus V. Kräusel D. Landgrebe L. Kroll Professorship of Management Accounting and Control Chemnitz University of Technology Thüringer Weg 7 09126 Chemnitz Germany Professorship Virtual Production Engineering Chemnitz University of Technology Reichenhainer Straße 70 09126 Chemnitz Germany Professorship for Forming and Joining Chemnitz University of Technology Reichenhainer Straße 70 09126 Chemnitz Germany Department of Lightweight Structures and Polymer Technology Chemnitz University of Technology Reichenhainer Straße 31/33 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

To ensure a successful development of resource-efficient and sustainable technologies, products, and production processes, it is essential to support R&D activities in early design stages. Thus, amongst others an appropriate assessment should be accomplished, which captures the high complexity and interdependencies of process chains, considers the technological feasibility, the energetic and economic benefit as well as the robustness as facets of resource efficiency, and hence, serves as a basis for deriving impulses for R&D activities. A promising evaluation methodology for such assessments is the Multidimensional Evaluation Method for Process Chains of HybrId Structures (MEMPHIS). In this paper, MEMPHIS is outlined and illustrated for an innovative process chain for producing hybrid laminates with sensor functionality. As a result, the paper will contribute to the further development of the methodology, show its applicability, and provide insights into the innovative technology.

关键词： cost effectiveness energy efficiency hybrid assembled composites robustness sustainable manufacturing processes

来源：评论

学校读者我要写书评

暂无评论

Study on the Influence of the Processing Speed in the Generation of Complex Geometries in Aluminium Matrix Composites by Electrochemical Precision Machining

引用

Procedia CIRP 2018年 68卷 713-718页

作者： Norbert Lehnert Gunnar Meichsner Matthias Hackert-Oschätzchen André Martin Andreas Schubert Professorship Micromanufacturing Technology Chemnitz University of Technology 09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology 09126 Chemnitz Germany

Currently, an increasing demand for lightweight materials with a high strength can be observed. Potential materials, which fulfil these requirements, are particle reinforced aluminium matrix composites (AMCs). AMCs consist of an aluminium matrix, which is reinforced by ceramic particles. In a consequence, AMCs offer a strength, which is comparable to steel, along with a density, which is comparable to light metals. In the Collaborative Research Centre SFB 692 at Chemnitz University of technology, AMCs are analysed under different research aspects. One of these aspects is the generation of complex geometries by Electrochemical Precision Machining (PECM). The investigated AMC consists of ENAW 2017, which is reinforced by 10% of SiC-particles. To achieve the desired complex geometry, the dissolution characteristic of the specific AMC was analysed. Furthermore, the achievable surface quality was characterised. Based on these fundamental results, processing strategies for generating complex geometries in AMCs by PECM were derived. In this study, the influence of the PECM processing speed on the resulting complex geometry is investigated. For that purpose, a model geometry based on a retarder was selected and realized. The resulting side gap and the front gap as a function of an increasing processing voltage and an increasing feed rate are presented. It can be stated that the side gap can be reduced by an increase in feed rate.

关键词： Electro chemical machining (ECM) Metal matrix composite Aluminium Silicon carbide

来源：评论

学校读者我要写书评

暂无评论

Derivation of Guidelines for Reliable Finishing of Aluminium Matrix Composites by Jet Electrochemical Machining

引用

Procedia CIRP 2018年 68卷 471-476页

作者： Norbert Lehnert Matthias Hackert-Oschätzchen André Martin Andreas Schubert Professorship Micromanufacturing Technology Chemnitz University of Technology 09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology 09126 Chemnitz Germany

The Collaborative Research Centre SFB 692 at Chemnitz University of technology is focused on aluminium-based light-weight materials in safety-related parts and components. One field of activity are aluminium matrix composites (AMCs). Thereby, the manufacturing, the mechanical properties, the economic opportunities and challenges as well as the machinability are investigated. One of the research focusses is the finish-machining of AMCs by Jet Electrochemical Machining (Jet-ECM). Therefore, one objective is to achieve guidelines for reliable machining of AMCs by Jet-ECM. In a first step the dissolution characteristic of EN AW 2017 with 10% of SiC particles, which was manufactured within the SFB 692, was analysed by help of a microcapillary cell, applying a sodium nitrate electrolyte. Furthermore, Jet-ECM was used to generate point erosions using different pH-neutral electrolytes, namely NaNO 3 and NaCl. AMCs made of the aluminium alloy EN AW 2017 with 0%, 5% and 10% SiC particles were machined with a maximal voltage of 25 V. In the current study the parameter field is extended further. The dissolution characteristic by using the pH-neutral electrolyte sodium-bromide is analysed and the voltage range is set to 60 V. Those experiments show, that each electrolyte causes a specific dissolution characteristic. Based on the experimental data, guidelines for a reliable finishing of AMCs by Jet-ECM are derived. The resulting guidelines can be used to predict the depth of the point erosions as function of particle fraction, the applied voltage and the machining time, with respect to the used electrolyte. The statistical evaluation of the guidelines show, that the applied voltage and the machining time are the dominant factors to control the dimensions of the point erosions. Whereas the particle fraction has a minor effect on depth and width.

关键词： Electro chemical machining (ECM) Metal matrix composite Aluminium Silicon carbide

来源：评论

学校读者我要写书评

暂无评论

Identification of modal parameters of machine tools during cutting by operational modal analysis

引用

Procedia CIRP 2018年 77卷 473-476页

作者： Jan Berthold Martin Kolouch Volker Wittstock Matthias Putz Technische Universität Chemnitz Professorship for Machine Tools and Forming Technology Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Reichenhainer Str. 88 09126 Chemnitz Germany

The dynamic behaviour of machine tools differs between standstill and process state. Operational modal analysis (OMA) makes possible to identify modal parameter under process conditions. In this paper, it is shown, how far the assumption of a time-invariant behaviour as well as a broadband excitation can be fulfilled by exciting the machine with a cutting process. After describing the dynamic behaviour in the work space to determine a time-invariant tool path, a broadband excitation is generated by changing cutting parameters during milling. The modal parameters are identified by different OMA methods and compared to results of the experimental modal analysis.

关键词： machine Tool Dynamics Operational Modal Analysis

来源：评论

学校读者我要写书评

暂无评论

Thermal and Mechanical Joining of Basalt Fiber Reinforced Thermoplastic Laminates

引用

IOP Conference Series: Materials Science and Engineering 2020年第1期947卷

作者： A Al-Obaidi P Rochala M Kroll T Hahn V Kräusel Chemnitz University of Technology Institute for Machine Tools and Production Processes Professorship for Forming and Joining 09107 Chemnitz Germany Nordmetall GmbH –Materials and Impact Engineering Adorfer Hauptstraße 16 09221 Neukirchen/Adorf Germany

In this paper, quasi-isotropic basalt fiber reinforced polyamide PA6 was joined to aluminum sheets using three different joining technologies. The joints were manufactured by means of nut and bolt (NAB) as well as two-piece hollow riveting (TPHR) as current state of the art processes. Furthermore, additional joints were established by the new inductive contact joining (ICJ) technology. The obtained specimens were compared by means of tensile shear tests and by analysis of the fractured surfaces. It was found that the joints produced by ICJ are superior in comparison to joints manufactured by TPHR with regard to joint strength. In addition, during ICJ, the fibers of the polymer material are not damaged and the strength of the base material is maintained. Further optimization potential of the ICJ process was discovered during the investigations, so that potentially higher joint strengths as well as shorter process times can be expected, making the process interesting for future industrial applications.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A quasi-online geometric errors compensation method on CNC machine tool

A quasi-online geometric errors compensation method on CNC m...

引用

MECHATRONIKA International Symposium

作者： Tomas Marek Jan Berthold Michal Holub Joachim Regel Department of Production Machines Brno University of Technology Brno Czech republic Professorship for Machine Tools and Forming Technology Technische Universität Chemnitz Chemnitz Germany

ISBN: (纸本)9781538643648;9788021455429

The design of the quasi-online geometric errors compensation method on CNC machine tool using the Ballbar device is described. Nowadays, control and compensation of CNC machine tools are essential phases of their operation. The control is usually manual; the operator and the measuring apparatus jointly perform the measurement and subsequent machine compensation. The present paper describes the procedure and the experiment designed to assess machine condition under various operating conditions. The principle of performed machine tests is based on circular interpolation in manual regime. Prior to experiments, relevant evaluations are made, and quasi-online compensation is devised. For circularity measurement, the DMU 125 P DuoBlock CNC machining centre was chosen.

关键词： machine tools Measurement uncertainty Loading Machining Sensor systems Shape

来源：评论

学校读者我要写书评

暂无评论

Evaluation of manufacturing processes for the production of graded ultrafine grained materials

引用

Procedia Manufacturing 2018年 21卷 45-52页

作者： D. Landgrebe U. Götze M. Bergmann A. Schmidt R. Selbmann Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 09126 Chemnitz Germany Technische Universität Chemnitz Professorship of Management Accounting and Control 09107 Chemnitz Germany

Scientific research results show that graded ultrafine grained aluminum-based materials offer technical advantages by possible material property improvements (e.g. yield strength, corrosion resistance) especially when applied to heavily stressed components like screws. The commercial screw production is currently conducted without gradation of the semi-finished workpiece. Until now there is no evaluation on whether and under which conditions graded materials (screws) can technically and economically compete with conventional materials. In this paper, an innovative process chain for the production of graded ultrafine grained components is presented and analyzed based on a methodology for an integrated technical-economic evaluation. The evaluation especially of the yield strength of graded materials, energy consumption of the forming steps, energy costs, and revenue effects of improved material properties will outline the technical and economic potential of the technology. Despite higher energy consumptions positive profit effects can be expected due to improved material properties.

关键词： Severe Plastic Deformation aluminium screw technical-economic evaluation process chain evaluation

来源：评论

学校读者我要写书评

暂无评论

Biomechanical validation of additively manufactured artificial femoral bones

引用

BMC biomedical engineering 2022年第1期4卷 6页

作者： F Metzner C Neupetsch A Carabello M Pietsch T Wendler W-G Drossel ZESBO Centre for Research on Musculoskeletal Systems Leipzig University Semmelweisstraße 14 04103 Leipzig Germany. florian.metzner@medizin.uni-leipzig.de. Department of Orthopaedics Trauma and Plastic Surgery Leipzig University Leipzig Germany. florian.metzner@medizin.uni-leipzig.de. Department of Orthopaedics Trauma and Plastic Surgery Leipzig University Leipzig Germany. Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany. Professorship of Adaptronics and Lightweight Design Chemnitz Universtiy of Technology Chemnitz Germany. ZESBO Centre for Research on Musculoskeletal Systems Leipzig University Semmelweisstraße 14 04103 Leipzig Germany.

Replicating the mechanical behavior of human bones, especially cancellous bone tissue, is challenging. Typically, conventional bone models primarily consist of polyurethane foam surrounded by a solid shell. Although nearly isotropic foam components have mechanical properties similar to cancellous bone, they do not represent the anisotropy and inhomogeneity of bone architecture. To consider the architecture of bone, models were developed whose core was additively manufactured based on CT data. This core was subsequently coated with glass fiber composite. Specimens consisting of a gyroid-structure were fabricated using fused filament fabrication (FFF) techniques from different materials and various filler levels. Subsequent compression tests showed good accordance between the mechanical behavior of the printed specimens and human bone. The unidirectional fiberglass composite showed higher strength and stiffness than human cortical bone in 3-point bending tests, with comparable material behaviors being observed. During biomechanical investigation of the entire assembly, femoral prosthetic stems were inserted into both artificial and human bones under controlled conditions, while recording occurring forces and strains. All of the artificial prototypes, made of different materials, showed analogous behavior to human bone. In conclusion, it was shown that low-cost FFF technique can be used to generate valid bone models and selectively modify their properties by changing the infill.

关键词： 3D-printing 3d-printing Additive manufacturing Artificial bone Biomechanics Bone model Femoral Femur Hip

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：