The paper describes the status of research concerning the flexibilization of contact faces. For an extensive use of systems for flexible car body fixtures it is necessary to develop flexible contact elements to adapt ...
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The paper describes the status of research concerning the flexibilization of contact faces. For an extensive use of systems for flexible car body fixtures it is necessary to develop flexible contact elements to adapt the clamp to diverse part faces. For this different approaches are shown. Especially the approach of using shape-memory material to make contact faces flexible is discussed. Selected experiments were done. This was the first time the shape-memory effect has been shown on voluminous bodies. The material was activated using an induction field via filler. This way of activating voluminous bodies also has been shown for the first time. The usability of shape-memory polymers was demonstrated and the next steps were shown.
Within a research project at the fraunhofer Institute for machinetools and formingtechnologyiwu, vibration description methods are applied using the example of an air conditioning unit (AC unit) from a railway vehi...
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ISBN:
(纸本)9781632662675
Within a research project at the fraunhofer Institute for machinetools and formingtechnologyiwu, vibration description methods are applied using the example of an air conditioning unit (AC unit) from a railway vehicle. The AC unit consists of several components, where usually the compressors and fans contribute most to the radiated sound power resp. to the transmitted structure-borne sound into the vehicle. In a first step, forces F and accelerations a under steady-state conditions were measured on each of the six mounting brackets of the air conditioning unit. Afterwards, all of the dominant vibration sources of the unit were investigated individually concerning their contribution at each of their contact points. Finally, knowing the mobilities Y of the contact points between sources and unit enables detailed analysis of the system itself. Moreover, it also indicates "weak points" which have to be avoided according to an improved vibrational behavior of the complete air conditioning unit.
The air conditioning unit (AC unit) is one of the major sound sources for exterior and interior noise of a railway vehicle. The design of such devices is a compromise between main functions like efficiency, fluid mech...
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In the majority of cases, aluminium matrix composites (AMCs) consist of a relatively ductile matrix and hard ceramic particles embedded therein. In addition to an increased tool wear, machining of these materials invo...
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ISBN:
(纸本)9780956679024
In the majority of cases, aluminium matrix composites (AMCs) consist of a relatively ductile matrix and hard ceramic particles embedded therein. In addition to an increased tool wear, machining of these materials involves surface imperfections like voids and scaling. An approach to reduce the generation of suchlike imperfections is a modification of the cutting edge geometry. Turning tests have shown that smooth surfaces can be generated by using natural diamond tipped tools with a very small clearance angle of approximately 0.5 and a minor feed of 0.05 mm.
Simulation is established within the development process in order to validate technical systems at an early stage. Nonetheless, the required level of detail and the late availability of simulation models limit an econ...
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Simulation is established within the development process in order to validate technical systems at an early stage. Nonetheless, the required level of detail and the late availability of simulation models limit an economic application. This paper describes a novel approach for an interactive and mechatronic design of technical alternatives at early stages of development and in this regard the evaluation with physically based simulation models.
Micro-EDM is a well-known process for precision micro machining of difficult to cut materials. It is especially beneficial when machining complex micro structures such as deep bores, grooves or undercuts in highly wea...
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Micro-EDM is a well-known process for precision micro machining of difficult to cut materials. It is especially beneficial when machining complex micro structures such as deep bores, grooves or undercuts in highly wear resistant materials. One constraint is its limitation to electrically conductive materials. Advanced materials such as high-temperature resistant engineered ceramics are gaining more and more importance, nonetheless due to their manifold applications in transport, energy and also biomedical areas. An adaption of micro-EDM to nonconducting ceramics could bring together the design freedom implemented in the EDM process and the beneficial material properties of engineered ceramics. In the last years, research has successfully applied the assisting electrode method to zirconia material, allowing for the micro-EDM to proceed notwithstanding the electrically nonconducting properties. Using suitable dielectric and process parameters, the machining continues even after the electrically conducting starting layer has been removed. Within this study the micro-EDM milling of zirconia is investigated in order to further understand the mechanisms of ceramics machining. Roughness and surface characteristics are analyzed and compared to the equivalent metal parts. The voltage and current signals are recorded using high speed deep memory A/D converters to allow for an insight into the process. With the findings the process can be improved in terms of speed, accuracy and achievable structures.
Hybrid machining processes using additional energy sources such as laser assisted machining (LAM) have increased considerably during the last years. The benefits of LAM for reducing tool wear and cutting forces are we...
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Hybrid machining processes using additional energy sources such as laser assisted machining (LAM) have increased considerably during the last years. The benefits of LAM for reducing tool wear and cutting forces are well known, especially for superalloys. However, optimal machining results depend on both the laser parameters and the cutting process parameters. It is difficult to find optimal LAM settings due to the complexity of the influencing parameters and their mutual interactions. The aim of the paper is to characterize the laser heating process by detecting how the individual LAM parameters influence working temperature, heat affected zone (HAZ) extension and laser track width. A reliable application requires a localized and controlled continuous heating of the material within the machining zone directly in front of the tool contact area. In this research statistical and technological knowledge is fully involved in the experimental activities. Therefore, a statistical study based on design of experiment (DoE) was carried out in order to investigate the effects of laser process parameters and their interactions. In practice, two-level fractional factorial design and analysis of variance (ANOVA) were applied. The following process parameters were examined: laser power, scanning speed, defocus (the distance between focal point and workpiece surface), temperature controlled by pyrometer, and surface roughness. Furthermore, a Finite Element (FE) model was developed based on experimental results in order to find out the optimal parameters for modeling the laser heating process. Future FE simulations of the laser assisted cutting processes will be carried out using this model of the moving laser source.
Linked data can be used to connect information stemming from usually disparate sources. The Semantic Web combines various kinds of logical reasoning for the inference of additional knowledge from existing data and for...
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Linked data can be used to connect information stemming from usually disparate sources. The Semantic Web combines various kinds of logical reasoning for the inference of additional knowledge from existing data and for consistency checking of data sets. Although mathematics is crucial for most areas where Semantic Web technologies can be applied, support for them is lacking from related standards and tools. This paper presents an approach for integrating OpenMath with RDF data for the representation of mathematical relationships and the integration of mathematical computations into reasoning systems.
Grain refinement by the application of very high strains with changing strain path is an outstanding approach for tailoring material properties. Methods of severe plastic deformation (SPD) can create ultrafine-grained...
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