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Study on the mechanism of inhomogeneous microdamage in short-pulse laser processing of carbon fiber reinforced plastic

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JOURNAL OF REINFORCED PLASTICS AND COMPOSITES 2021年第15-16期40卷 568-576页

作者： Xu, Luyao Lu, Jiuru Li, Kangmei Hu, Jun Donghua Univ Sch Mech Engn Shanghai Peoples R China

In this article, a micro-heterogeneous material simulation model with carbon fiber and resin phase about laser ablation on carbon fiber reinforced plastic (CFRP) is established by Ansys. The ablation process of CFRP by nanosecond ultraviolet laser is simulated, and the mechanism of pulse energy and spot spacing on the heat-affected zone (HAZ) is studied, then the process parameters are optimized with the goal of HAZ size and processing efficiency, and finally the validity of the model is verified by experiments. It is found that the residual gradient and the width of the radial HAZ increase with the increase of the spot spacing, and the width of the axial HAZ decreases slightly with the increase of the spot spacing, which indicates the existence of the optimal spot spacing. Second, the ablation depth increases with the increase of the pulse energy, and the carbon fiber retains a relatively complete degree of exposure when the pulse energy is low, which has a certain guiding significance for the cleaning and bonding of CFRP.

关键词： carbon fiber reinforced plastic micro-simulation model heterogeneous materials heat-affected zone residual gradient optimization of process parameters

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Selective laser melting of a beta-solidifying TNM-B1 titanium aluminide alloy

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JOURNAL OF MATERIALS processING TECHNOLOGY 2014年第9期214卷 1852-1860页

作者： Loeber, Lukas Schimansky, Frank Peter Kuehn, Uta Pyczak, Florian Eckert, Juergen Leibniz Inst Solid State & Mat Res Dresden Dresden Germany Helmholtz Zentrum Geesthacht Ctr Mat & Coastal Re Geesthacht Germany

The interest for a wider range of useable materials for the technology of selective laser melting is growing. In this work we describe a new way to optimize the process parameters for selective laser meltingof a beta solidifying titanium aluminide. This kind of material has so far not been processed successfully by this method. The new approach is easy to conduct and well transferable to other materials. It is based on the fact that the parts generated from selective laser melting can be described by an addition of multiple single tracks. Multiple types of single track experiments are performed and in combination with knowledge from laser welding tests optimized parameter combinations are derived. Compact samples are built with the optimized process parameters and characterized in terms of microstructure, phase composition and mechanical properties. With this technique the generation of a TNMB1 titanium aluminide alloy sample with a density greater than 99% could be achieved. The mechanical properties are comparable with material produced by conventional techniques. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Additive manufacturing Selective laser melting Titanium aluminide Mechanical properties optimization of process parameters

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processability and Microstructural Evolution of W360 Hot Work Tool Steel by Directed Energy Deposition

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METALS AND MATERIALS INTERNATIONAL 2024年第2期30卷 501-516页

作者： Vincic, Josip Aversa, Alberta Lombardi, Mariangela Manfredi, Diego Politecn Torino Dept Appl Sci & Technol DISAT Corso Duca Abruzzi 24 I-10129 Turin Italy Ctr Sustainable Future Technol CSFT Polito Ist Italiano Tecnol IIT Via Livorno 60 I-10144 Turin Italy

Laser directed energy deposition (L-DED) was used to produce samples of the newly patented W360 hot work tool steel by Bohler. The process parameters were optimized to obtain nearly fully dense samples through the production and analysis of single deposited tracks and single layers. Subsequently, bulk samples underwent a hardening heat treatment, consisting of austenitizing, air quenching, and tempering. The samples were analysed in the as-built condition (AB), after quenching (Q) and following tempering cycles (HT) to observe the microstructural evolution. The microstructure was investigated using optical and scanning electron microscopes, energy dispersive X-ray analysis, and X-ray diffraction analysis. Furthermore, the microstructural evolution was analysed with differential scanning calorimetry, while the mechanical response was evaluated through microhardness test. It was found that the AB samples exhibited a dendritic-cellular microstructure with tempered martensite laths. The thermal history of the AB samples was completely modified by the austenitizing treatment followed by quenching, resulting in a fully martensitic Q sample that did not display the typical dendritic-cellular microstructure of the L-DED process. The completion of the heat treatment with tempering cycles revealed the presence of Mo-rich carbides dispersed in a martensitic matrix. The HT samples exhibited a mean microhardness of 634 HV, remaining constant along the entire building direction from the substrate to the last deposited layer, indicating a homogeneous microstructure. This high value, similar to other hot work tool steels such as H13, makes W360 a very promising candidate for tool build and repair purposes.

关键词： Additive manufacturing Laser directed energy deposition (L-DED) Hot work tool steel W360 optimization of process parameters Heat treatment Microhardness

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Multi-objective optimization of laser welding parameters for steel/Al based on Kriging-MSSA

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WELDING IN THE WORLD 2024年第12期68卷 3229-3230页

作者： Zhu, Zhi-wei Guo, Yong-huan Zhang, Xin-ran Lu, Xiang-ning Hua, Jun-yi Jiangsu Normal Univ Sch Mechatron Engn Xuzhou Peoples R China

In the context of automotive lightweighting strategy, steel/aluminum hybrid structures are widely used in the automotive industry. To address the reliability of steel/aluminum dissimilar metal joints, this study conducted steel/aluminum dissimilar metal laser welding tests by Taguchi’s design of experiments method and obtained relevant data. Based on the test results, a Kriging model with laser power, welding speed, and defocusing amount as inputs, and base material deformation and welded joint tensile strength as outputs was established. In this paper, with the amount of deformation of base material and tensile strength of welded joints after welding as the optimization objectives, the optimization analysis is carried out by combining the Kriging model and the multi-objective bottled sea-sheath swarm optimization algorithm (MSSA). The results show that under the conditions of laser power of 450 W, welding speed of 11.88 mm/s, and defocusing amount of 5.3 mm, the optimization objective reaches the optimal level, the base material warpage deformation is reduced by 22.33% compared with the pre-optimization, and the tensile strength of the welded joints is improved by 18.01%.

关键词： Dissimilar metal welding Kriging model Laser welding MSSA optimization of process parameters

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Systematic evaluation and optimization of crystallization conditions for vancomycin purification

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KOREAN JOURNAL OF CHEMICAL ENGINEERING 2010年第5期27卷 1538-1546页

作者： Lee, Ji-Yeon Lee, Kang-Hee Chae, Hee-Jeong Kim, Jin-Hyun Kongju Natl Univ Dept Chem Engn Kong Ju 314701 South Korea Hoseo Univ Dept Food & Biotechnol Asan 336795 South Korea

This study describes the evaluation and optimization of a crystallizing process capable of efficiently purifying vancomycin in high purity and yield. In particular, we observed how the main process parameters influenced the formation of crystals, determined their morphology, and monitored purity and yield. Acetone was shown to be more effective than alcohol solvents for the crystallization of vancomycin. The optimal distilled water/acetone ratio, storage temperature, storage time, pH, conductivity, initial vancomycin concentration and stirrer velocity were shown to be 1:3.5 (v/v), 10 degrees C, 24 h, pH 2.5, 20 ms/cm, 0.1 g/mL, and 640 rpm, respectively. Temperature had a decisive influence on crystal formation;crystals were successfully produced at 10 degrees C, while at other temperatures, conglomeration, disintegration and cohesion occurred. Crystal growth developed over time and was complete at about 24 h. Vancomycin purity remained at about 97.0% irrespective of storage time while the yield increased over time, reaching a maximum of 95.0% at around 24 h, after which there was no substantial change. Crystallization occurred over a certain range of pH (2.5-3.0), but purity and yield were highest at pH 2.5. When the pH was outside this range, a conglomeration (gelation) phenomenon prevented the efficient production of crystals. Vancomycin crystals were produced irrespective of the stirrer velocity, which had no influence on purity;however, the highest yield of vancomycin was obtained at 640 rpm.

关键词： Vancomycin Crystallization Purification optimization of process parameters Identification of Morphology

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Signal enhancement of protein chips

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SENSORS AND ACTUATORS B-CHEMICAL 2005年第1期107卷 178-183页

作者： Sauer, U Preininger, C Krumpel, G Stelzer, N Kern, W ARC Seibersdorf Res GmbH Div Environm & Life Sci Dept Bioresources A-2444 Seibersdorf Austria Dept Mat Sci A-2444 Seibersdorf Austria Graz Tech Univ Inst Chem & Technol Organ Mat A-8010 Graz Austria

Biochip technology has been revolutionizing most fields of molecular biology. One of the main issues confronting further development of biochip technology is the strength of signals produced by probe-target interaction, especially in cases of low probe and target concentrations. In order to achieve stronger signals and lower detection limits, we aim at (a) the optimization of chip process parameters, (b) the use of gold particles as labels in surface-enhanced fluorescence detection and (c) increasing surface reflectivity by the addition of SiO2 and TiO2 layers. process parameters optimized were print buffer, humidity control during arraying, and probe concentration. Surface chemistries, such as porous poly(styrene-co-4-vinylbenzylthiocyanate) (PST-co-VBT) and epoxy resin, have been tested as to their suitability for protein attachment. Surface enhanced fluorescence (SEF) was observed as a result of processing the array using Dy633- and Au-labelled target in different ratios. Enhancement of the reflectivity was achieved by incorporating high-index refractive TiO2 layers between two low-refractive polymer layers or between the glass substrate and the polymer layer by means of hydrothermal synthesis of nanostructured TiO2 particles or sol-gel technology. The characteristics of these interference coatings differed as to the refractive index of the layers, the film thickness and the stack design. (c) 2004 Elsevier B.V. All rights reserved.

关键词： reflective coatings surface enhanced fluorescence protein chip optimization of process parameters

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Direct synthesis of benzyl acetate and optimisation of reaction conditions for the gas phase acetoxylation of toluene

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CATALYSIS TODAY 2006年第1-4期112卷 192-196页

作者： Benhmid, A Narayana, K Martin, A Lücke, B Pohl, MM Inst Angew Chem Berlin Adlershof eV D-12489 Berlin Germany

TiO2 supported Pd-Sb catalysts were prepared by impregnation method and tested for the selective vapour phase acetoxylation of toluene to benzyl acetate (BA). Investigations were carried out to optimise reaction variables such as effects of reaction temperature, acetic acid/toluene mole ratio, O-2/toluene mole ratio, contact time, etc. to obtain better performance of the catalysts. Additionally, the influence of Sb/Pd ratio on catalytic performance was also checked under optimised reaction conditions. The activity of the catalysts was found to increase continuously with increasing Sb/Pd ratio up to 0.7 and then decreased with further increase in Sb/Pd ratio to 1.75. The catalyst with Sb/Pd ratio of 0.7 exhibited the best performance among all other catalysts of this series giving a conversion of toluene as high as ca. 68% with BA selectivity of 85%. All these catalysts were observed to deactivate with time on stream due to considerable amount of coke deposition. However, these catalysts can be regenerated in air and reused for more number of cycles with consistent performance. (c) 2005 Elsevier B.V. All rights reserved.

关键词： gas phase acetoxylation toluene Sb-Pd/TiO2 catalysts optimization of process parameters Sb/Pd ratio

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optimization Design Based on DEFORM-3D Finite Element Analysis about Steel Rolling Production

Optimization Design Based on DEFORM-3D Finite Element Analys...

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International Conference on Materials Engineering for Advanced Technologies (ICMEAT2011)

作者： Ren, Jianhua Wang, Wei Liu, Rong Hebei Univ Engn Handan 056038 Hebei Peoples R China Xingtai Iron & Steel Co LTD Xingtai 054027 Hebei Peoples R China

ISBN: (纸本)9783037851319

This paper took the high-speed wire rod rolling process of phi 20 bar as the research object, to be simulated numerically under the work platform of the finite element software DEFORM. The simulation results were compared with the actual operation of the production process, the rolling simulation reappeared the actual production situation, realized the visualization of the rolling process. After analysis, the defects of rolling technology were found out. Based on the research, the optimum design was gotten and then simulated which improved the actual production process and avoided the original defects. The optimum design is feasible to practical production and reduce the cost of test in practice The paper just focused on the first one of 12 rolling process as an example to show the simulating process and results.

关键词： High-speed wire steel Rolling DEFORM-3D finite element simulation optimization of process parameters

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optimization of Machining process for Aluminum Alloy Thin-walled Supporting Part on UG NX

Optimization of Machining Process for Aluminum Alloy Thin-wa...

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International Conference on Material and Manufacturing Technology

作者： Hao Yishu Zhang Baogang Cui Xu Tongji Univ Coll Mech Engn Shanghai 201804 Peoples R China

ISBN: (纸本)9780878492435

According to the structural features of the supporting part, the manufacturing process plan of it is made and the fixtures are designed. The process parameters are optimized by the means of setting up multi-objective function that cover productivity, cost of production. processing efficiency;The NC Programs of supporting part are drawn with UG CAM and the machining tool-path is optimized through machining simulation.

关键词： UG NX CAM/CAE Supporting part optimization of process parameters Multi-objective function

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Simulation research on wafer warpage and internal stress in the First Passivation process of eSiFO package 19

Simulation research on wafer warpage and internal stress in ...

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19th International Conference on Electronic Packaging Technology (ICEPT)

作者： Yuan, Shichao Yu, Huiping Xiang, Min Cai, Anwen Yu, Daquan Qin, Fei Beijing Univ Technol Inst Elect Packaging Technol & Reliabil Beijing Peoples R China Huatian Technol Kunshan Elect Co Ltd Kunshan Peoples R China

ISBN: (纸本)9781538663868

In the electronics packaging process, warpage and thermal stress are two important causes which lead to packaging failure. In this paper, ABAQUS is used to perform three-dimensional numerical simulation of eSiFo packaging products from the thermodynamic point of view. The effects of different structural parameters on wafer warpage and thermal stress in electronic packages are simulated. In the simulation part, single factor analysis, Taguchi orthogonal experiment design and finite element analysis are combined to obtain the optimized process parameters and perform simulation analysis. The result shows that the structural parameter that has the greatest influence on the von Mises stress value of the wafer is the window size. And the structural parameter that has the greatest influence on the wafer warpage is the Die thickness. The thickness of the adhesive layer and the thickness of the passivation layer have a relatively small effect on the von Mises stress and the warpage value of the wafer. Under the optimized process parameters, the maximum von Mises stress and the maximum warpage value are much smaller than the initial process.

关键词： Warpage thermal stress numerical simulation Taguchi orthogonal experiment optimization of process parameters

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