检索结果-南通市图书馆

Identification of Characteristic Values in Impulse-Based Processes Using Small Specimens

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nanomanufacturing and Metrology 2022年第3期5卷 310-323页

作者： Tobias Valentino Tim Radel bias-Bremer Institut Fur Angewandte Strahltechnik GmbH Klagenfurter StraBe 528359 BremenGermany

Suitable approaches are needed for rapid and cost-efficient materials ***-throughput experimentation reduces the identification time of suitable material *** approach is to use small specimen geometries to save additional production ***,research is continuously being conducted on a new hardness test based on laser-induced shock *** far,characteristic values from the induced indentations have been extracted,which correlate with hardness and tensile ***,the indentation result varies in dependence of the specimen size and *** condition hinders the correlation between characteristic values and material ***,the goal was to induce similar indentation results to minimum specimen ***,different mounting materials and methods were *** created indentations were compared with those induced in large *** mounting parameters were derived from the ***,small specimens can be used for material characterization by considering these mounting parameters.

关键词： Mounting Stiffness Coefficient of restitution Forming efficiency Measuring instrument TEA-CO_(2)laser

A deformation and 3D-shape measurement system based on phase-shifting digital holography

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A deformation and 3D-shape measurement system based on phase...

Improving thermal efficiency and stability of laser welding process for magnesium alloy by combining power modulation and subatmospheric pressure environment

ICEM 2001 The 3～(rd) International Conference on Experimental Mechanics

作者： Ervin Kolenovi Wolfgang Osten Werner Jüptner bias GmbH Klagenfurter Str. 2 28359 Bremen Germany bias GmbH Klagenfurter Str. 2 28359 Bremen Germany bias GmbH Klagenfurter Str. 2 28359 Bremen Germany

＜正＞ Digital holography provides the possibility to combine deformation measurement and surface contouring in one experimental setup. However, digital holography systems are commonly available only as laboratory setups. Due to a number of disadvantages those laboratory setups are not suitable to realize a flexible digital holography system that can easily be used in different environments, such as in cavities. In this paper we introduce a highly optimized measurement system based on digital holography which was especially designed to be used as an endoscopic sensor. The system is able to measure both the shape and the deformation of an object. The sensor makes it possible to use the advantages of digital holography and additionally it has a high flexibility. To realize this kind of system the sensor module itself as well as the reconstruction algorithm have to be applied several demands. These demands include a small sensor size, the ability to measure relatively large objects and a high processing *** very small dimensions of the sensor could only be achieved by the use of analog inspection cameras. To take full advantage of the space bandwidth product （SBW） of these CCD devices, in-line holography in combination with temporal phase-shifting has been used. This gives the possibility to investigate larger objects than by using off-axis recording setup. In order to receive a high processing speed a new algorithm which was recently introduced by the authors was used to eliminate the complex conjugated twin image and the zero order beam in in-line holography. Concerning this application the algorithm shows relevant advantages compared to other known *** experimental results presented in this paper include deformation measurements as well as shape measurements, both recorded with a first prototype of the introduced system. Those examples demonstrate that the developed system makes digital holography a useful tool even outside of a laboratory and that the me

关键词： Digital holography phase-shifting deformation measurement shape measurement

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第10期10卷 2788-2800页

作者： Jie Ning Suck-Joo Na Lin-Jie Zhang Xiang Wang Jian Long Won-Ik Cho State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China bias-Bremer Institut für angewandte Strahltechnik GmbH Klagenfurter Straße 528359 BremenGermany

The laser welding(LW)process of highly reflective materials presents low thermal efficiency and poor *** solve the problem,the effects of subatmospheric environment on LW process,technological parameters in subatmospheric environment on weld formation and welding with sinusoidal modulation of laser power on the stability of LW process in subatmospheric environment were *** AZ31magnesium(Mg)alloy was used as the test *** test result revealed that the weld penetration in subatmospheric environment can increase by more than ten times compared with that under normal *** the keyhole depth greatly rises,significantly periodic local bulge is observed on the backwall surface of the keyhole and the position of the bulge shifts along the direction of the keyhole ***,the hump-shaped surface morphology of the welded seam is formed;moreover,the weld width in local zones in the lower part of the welded seam remarkably *** LW in subatmospheric environment,the weld penetration can be further greatly increased through power ***,power modulation can inhibit the occurrence of bulges in local zones on the backwall of the keyhole during LW in subatmospheric environment,thus further curbing the significant growth of the weld widths of hump-shaped welding beads and local zones in the lower part of welded ***,the mechanism of synchronously improving the thermal efficiency and stability of LW process of highly reflective materials through power modulation in subatmospheric environment was *** was conducted according to theoretical analysis of recoil pressure and observation results of dynamic behaviors of laser induced plasma clouds and keyholes in the molten pool through high speed photography.

关键词： Laser welding Subatmospheric environment Power modulation Highly reflective materials Thermal efficiency Stability

Parallax limitations in digital holography: a phase space approach

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Light(Advanced Manufacturing) 2022年第3期3卷 76-83页

作者： Ulf Schnars Claas Falldorf private 27628 Hagen im BremischenGermany bias-Bremer Institut für Angewandte Strahltechnik GmbH Klagenfurter Str.528359 BremenGermany

The viewing direction in Digital Holography can be varied if different parts of a hologram are *** this article parallax limitations are discussed using the phase space *** equation for the parallax angle is derived with this formalism from simple geometric *** result is discussed in terms of pixel size and pixel number of the image *** of perspective is demonstrated experimentally by two numerical hologram reconstructions from different parts of one single digital hologram.

关键词： Digital holography Perspective Parallax Phase space

Model for a UV Laser Based Local Polymer Surface Halogenation Process Using a Gaseous Precursor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Modeling and Numerical Simulation of Material Science 2014年第1期4卷 14-19页

作者： Simon Kibben bias—Bremer Institut für Angewandte Strahltechnik GmbH Bremen Germany

An analytical model describing the physical relations of a UV-based process for halogenation of polymeric surfaces is presented. The process allows, depending on the parameters, a local halogenation with sharp edges at the interfaces to areas where no halogenation is desired. This is achieved via a nonreactive halogen-containing gaseous precursor and a UV source providing photons which dissociate the precursor photolytically. Thus, only where the UV photons affect the precursor, halogens are generated and the polymer is being halogenated.

关键词： Local Surface Halogenation Polymer Modification UV-Laser-Based Surface Modification

Ultraviolet Laser Based Gas Phase Fluorination of Polystyrene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Surface Engineered Materials and Advanced Technology 2014年第5期4卷 309-317页

作者： Simon Kibben Klaus Vogelsang bias—Bremer Institut für angewandte Strahltechnik GmbH Bremen Germany INNOVENT e.V. Jena Germany

A novel hybrid process for surface fluorination of polymers is being introduced. The process is based on ultra violet (UV) laser radiation, which on the one hand forms radicals out of an atmosphere of a partially fluorinated benzene, and on the other hand activates a polymer surface in the areas where the UV radiation hits the surface. The radicals can react with the polymer surface, hence altering the surface energy. With this process, a fluorine content of over 30% on the surface of bulk polystyrene can be achieved, while the smallest possible structure size was smaller than 1 mm.

关键词： UV-Laser Polymer Modification Local Fluorination

Process Window Expansion of Laser Chemical Machining by Using High Pressure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2020年第5期11卷 296-304页

作者： Marcel Simons Tim Radel Frank Vollertsen bias-Bremer Institut für Angewandte Strahltechnik Bremen Germany Faculty of Production Engineering-Mechanical Engineering & Process Engineering University of Bremen Bremen Germany

Laser Chemical Machining (LCM) is a non-conventional removal process, based on a precise thermal activation of heterogeneous chemical reactions between an electrolyte and a metallic surface. Due to local overheating during the process, boiling bubbles occur, which can impair the removal quality. In order to reduce the amount of bubbles, the laser chemical process is performed at different process pressures. Removal experiments were performed on Titanium Grade 1 using the electrolyte phosphoric acid at various process pressures, machining speeds and laser powers in order to determine the limit of the process window by evaluating the characteristics of the removal cavities. As a result, the process window for non-disturbed laser chemical machining is widened at higher process pressures. The process pressures have no influence on the geometric shape of the removal. The expansion of the process window is attributed to the fact that at higher process pressures the saturation temperature of the electrolyte rises, so that bubble boiling starts at a higher surface temperature on the workpiece induced by the laser power. The removal rate could be increased by a factor of 2.48 by increasing the process pressures from ambient pressure to 6 bar, thus taking an important step towards the economic efficiency of the laser chemical machining.

关键词： Micro Machining Laser Micro Machining Laser Chemical Removal Removal Rate Process Pressure

Thermal Analysis of Laser Chemical Machining: Part I: Static Irradiation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2017年第10期8卷 685-707页

作者： Hamza Messaoudi Sandro Eckert Frank Vollertsen bias—Bremer Institut für angewandte Strahltechnik Bremen Germany Faculty of Production Engineering-Mechanical Engineering & Process Engineering University of Bremen Bremen Germany

The laser chemical machining is a non-conventional substractive processing method. It is based on the laser-activation of a material dissolution of metals in electrolyte ambient via local-induced temperature gradients and allows a gentle and smooth processing of especially temperature-sensitive metals. However, the material removal is characterized by a narrow process window and is restricted by occurring disturbances, which are supposed to be related to the localized electrolyte boiling. In order to control the removal quality and avoid disturbances, the correlation between the laser-induced temperatures and the resulting removal geometry has to be better understood. In this work an analytical modeling of the laser-induced temperatures at the surface of titanium based on a Green-function approach is presented. The main influencing factors (laser, electrolyte, material) as well as possible heat transfer into the electrolyte are included and discussed. To verify the calculated temperatures, single spot experiments are performed and characterized for titanium in phosphoric acid solution within laser irradiation of 1 s. The correlation between the temperature distribution and the resulting removal geometry is investigated based on a spatial superposition. Thereby, the bottom limit temperature is found to range between 63°C and 70°C whereas the upper limit is related to the nucleate boiling regime. Based on the performed correlation an indicator is identified to predict the ruling removal regime and thereby to reduce the experimental expenditure.

关键词： Laser Micro Machining Laser Chemical Removal Modeling Temperature Process Stability Titanium

Process Signatures as a Measure for Loopless Production

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering（科研） 2017年第3期9卷 328-337页

作者： Tong Zhao Frank Vollertsen bias—Bremer Institut für angewandte Strahltechnik GmbH Bremen Germany University of Bremen Faculty of Production Engineering—Mechanical Engineering & Process Engineering Bremen Germany

Using control and repairing loops to remove production errors is not the only solution to increase the manufacturing yield. The production of errors can also be directly avoided, prevented or eliminated, even as early as in the planning phase. This paper suggests that the idea of Process Signatures can help to achieve Loopless Production. Loopless Production offers an option to guarantee the production quality towards the vision of the zero-defect manufacturing. It is considered that closed loops are used in a production process chain to identify and to correct the unknown and the systematic errors. These errors can actually be avoided through specifically adjusted or optimal arranged production processes. This puts a higher demand on the understanding of processes, which involve various energy-material interactions. This demand can be met via Process Signatures which aims to develop a process-independent description method of effects of processes. A supportive relationship is foreseen between Process Signatures and Loopless Production. The combination of these two ideas shall allow the simplification of the work for the rationalization of process sequences, the streamlining of closed loops as well as the selection of optimal substitute processes.

关键词： Unknown Error Systematic Error Process Chain Closed Loop Energy-Material Interaction