检索结果-内蒙古大学图书馆

Research of The Influence Mechanism of Multi Gradient Printing on Sand Mold Performance

Journal of Physics: Conference Series 2021年第1期1965卷

作者： LI Zheng Shan Zhongde Liu Feng Ran Yuelong State Key Laboratory of Advanced Forming Technology and Equipment Beijing National Innovation Institute of Lightweight Ltd. Beijing 100044 China Nanjing University of Aeronautics and Astronautics Nan jing 211106 China

In this paper, multi gradient sand mold sample printing was carried out based on the gray printing technology of sand mold 3D printing, and the influence of gradient distribution of resin addition in sand mold on the property of sand mold was studied. The results showed that the increase of resin addition gradient in sand mold would result in the decrease of tensile strength of sand mold with the constant total resin addition. The bending strength and air permeability of sand mold were mainly affected by the surface resin addition and gradient distribution. With increase of surface resin addition, The bending strength of sand mold decreased, and of which the air permeability increased at the same time. And the increase of gradient spacing between adjacent resin addition gradients in sand mold would lead to the increase of sand mold air permeability and the decrease of tensile strength and bending strength. The result also showed that The surface hardness of the sand mold increased with the increase of the resin content of the surface layer, and had nothing to do with the gradient distribution of the resin content.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Study on forming technology of Composite Micro-wire Made From AF and PLA

引用

Journal of Physics: Conference Series 2021年第1期1986卷

作者： ZOU Ailing SHAN Zhongde CHEN Yiwei WANG Shaozong LIU Xiaojun State Key Laboratory of Advanced Forming Technology and Equipment of China Academy of Machinery Science and Technology Beijing China Beijing National Innovation Institute of Lightweight ltd. Beijing China Nanjing University of Aeronautics and Astronautics Nanjing China

In order to improve the interlaminar shear property of the composites manufactured by the additive of aramid fiber (AF) reinforced with polylactic acid (PLA), the preparation process of AF reinforced thermoplastic resin composite micro-wires has been optimized, which could promote impregnated and toughness. The influence of different water bath temperatures on the interlaminar shear properties of the composites was studied. And the results showed that the largest interlaminar shear strength (ILSS) of AF/PLA composite material was 12.0 MPa, which had confirmed in the water bath temperature of 30°C. As the bath temperature increased, the interlaminar shear performance decreased, and the ILSS of composite micro-wires in 70°C water bath was 74.67% of that in 30°C water bath. The composite fiber with high impregnation degree and good toughness has laid a foundation for further research on additive manufacturing of AF/PLA composite.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Design and Structure Simulation Analysis of Sand-mold Inkjet Printing Device

引用

Journal of Physics: Conference Series 2021年第5期1885卷

作者： Yifei Wang Zhongde Shan Shuangfeng Wu Zhi Guo Shijie Dong shan Hu State Key Laboratory of Advanced Forming Technology and Equipment Beijing 100083 China Beijing National Innovation Institute of Lightweight Ltd Beijing 100083 China College of Material science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Ink-jet printing technology is a digital high-efficiency forming technology that can realize the rapid manufacturing of sand mold for foundry. This paper designs a low-cost, high-reliability ink-jet printing device based on the sand-mold inkjet printing process, and uses ANSYS finite element analysis software to carry out static analysis and modal analysis for its main frame. The analysis results show that the main frame has good rigidity and high strength, there will be no large deformation and resonance in frame under the working conditions, which can meet the requirements of sand-type inkjet printing devices.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Three-dimensional printing technology of zinc alloy fused and deposition

引用

Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) 2018年第7期52卷 1364-1369页

作者： Yang, Li-Ning Shan, Zhong-De Rong, Wen-Juan Liu, Feng Yang, Shuo State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing100044 China

A new three-dimensional printing technology based on fused and deposition was proposed in order to solve the high cost and low efficiency problems of the existing additive manufacturing technologies for metal parts. The technology is suitable for medium and low melting point metal material. The principle of the technology was introduced. The three-dimensional printing process of zinc alloy was conducted by using the self-developed equipment in order to analyze the effects of nozzle height, scanning speed and lapping rate on the forming effect. The width of single track was inversely proportional to height. When the nozzle height was 25~35 mm and the scanning speed was 8 mm/s, the single track quality was better. The surface quality of the deposited monolayer was better when the overlap ratio was 35%~40%. The density of the zinc alloy can be more than 97% by using the three-dimensional printing technology based on fused and deposition, and the density of the formed part can be enhanced by increasing the melting temperature, the temperature of the substrate, annealing temperature and annealing time. The technology can be used to realize the forming of the inner flow channel die with complex shape, which can reduce the processing difficulty and improve the forming efficiency. The tensile strength of zinc alloy solid was 198 MPa, the yield strength was 140 MPa, and the elongation was 0.453%, which were equivalent to those of conventional squeeze casting process. The microstructure of the zinc alloy solid was more refined. © 2018, Zhejiang University Press. All right reserved.

关键词： Deposition

来源：评论

学校读者我要写书评

暂无评论

Impact tensile cracking behavior of oxide scale in Q235 strip iron 2

Impact tensile cracking behavior of oxide scale in Q235 stri...

引用

2nd International Conference on Material Engineering and advanced Manufacturing technology, MEAMT 2018

作者： Wang, Shang Li, Wenpei Wang, Xiaochen Ai, Rui Yang, Quan Shan, Zhongde Institute of Engineering Technology University of Science and Technology Beijing Beijing100083 China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing100083 China

Scanning electron microscopy (SEM) is used to observe the fracture surface morphology of Q235 steel. The cracking law/crack rule principle of strip surface under tension is studied via universal tensile testing machine. The results show that the thickness of the scale is relatively uniform, about 10 μm, and the structure is dense and well attached to the matrix. Tensile experiments show that as the strain increases, the cracks increase slowly in the initial stage, rapidly in the middle period, and slowly in the final period. When the strain exceeds 0.15%, the cracks are difficult to increase. In order to avoid direct erosion of the abrasive on the substrate, a reasonable range of tension setting should be 0.15%-0.18% in the pretreatment process without acid descaling. © 2018 The Authors, published by EDP Sciences.

关键词： Tensile testing

来源：评论

学校读者我要写书评

暂无评论

Simulation of temperature field of A356 aluminum alloy in freeze casting

引用

Journal of Physics: Conference Series 2020年第1期1600卷

作者： Haoqin Yang Zhongde Shan Yifei Wang Limin Liu State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Group Co. Ltd. Beijing 100044 China

In this paper, the temperature change curve of the casting and frozen sand mould during the solidification process of the A356 aluminum alloy in the frozen sand mould is tested. According to the actual temperature change curve of the casting surface and the sand mould surface, the interface heat transfer coefficient between the frozen sand mould and the A356 aluminum alloy could be reversed analysis. The results show that when the casting temperature is lower than 550 °C, the interface heat transfer coefficient remains about 750 W.(m2.K)-1; When the casting temperature is between 550 °C and 610 °C, the interface heat transfer coefficient increases significantly; when the casting temperature is higher than 610 °C, the interface heat transfer coefficient reaches the maximum value, which is about 2300W. (m2.K) -1. At this time, this study simulates the solidification temperature field of aluminum alloy hub parts in the frozen sand mould according to the interface heat transfer coefficient calculated by inverse analysis, and the temperature field of resin sand mould casting was used as for comparison. The results show that: under the same solidification time, the temperature field of A356 aluminum alloy hub parts in frozen sand mould is lower than that of resin sand casting, freezing casting can realize the high-speed solidification process of different parts of complex castings.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Design of a New Engine Hood based on Lattice Structure for Pedestrian Protection

引用

Journal of Physics: Conference Series 2021年第1期1965卷

作者： Meng Liu Fuzhen Sun Baoming Wang Jianfeng Wang Na Yang State Key Laboratory of Advanced Forming Technology and Equipment Beijing 100044 P. R. China The University of Science and Technology Beijing 100083 P.R. China Weihai Guangwei Group Corporation Weihai 264200 P.R. China School of Automotive Engineering Harbin Institute of Technology Weihai 264209 P.R. China

This paper designs four kinds of three-dimensional negative Poisson's ratio lattice structures, based on the two-dimensional concave hexagonal negative Poisson's ratio honeycomb structure. Different parameters are designed for simulation analysis and experimental research, and the influence of different parameters on Poisson's ratio is studied respectively. The main contents are as follows: Firstly, the three-dimensional solid model of lattice structure is established by modeling software, and the different structural parameters are determined, and the equivalent mechanical model is established. And according to the relevant structural parameters to establish the test scheme. Then, the finite element software is used to simulate the test core material with different parameters. According to the simulation results, the influence of different parameters on Poisson's ratio is found out. Then the crashworthiness of the test board with different parameters is simulated and analyzed. According to the results, the most suitable structure is selected and applied to the engine hood. Finally, the simulation experiment of collision between pedestrian head and engine hood is carried out. The results of this paper compare the performance of lattice sandwich panels with different parameter structures in different tests and select the optimal combination of structural parameters. The adjustment and optimization direction of the structure is put forward according to the test results.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Study on Automobile Front-End Structure Based on Pedestrian Leg Protection

引用

Journal of Physics: Conference Series 2021年第1期1965卷

作者： Meng Liu Fuzhen Sun Baoming Wang Jianfeng Wang Na Yang State Key Laboratory of Advanced Forming Technology and Equipment Beijing 100044 P.R. China The University of Science and Technology Beijing 100083 P.R. China Weihai Guangwei Group Corporation Weihai 264200 P.R. China School of Automotive Engineering Harbin Institute of Technology Weihai 264209 P.R. China

According to the pedestrian leg protection regulations, a collision with the simplified finite element model of the leg was carried out on the basis of incorporating EPP foam materials with different foaming rates and cushioning into the simplified front-end structure of the car. The results show that the front-end foam energy-absorbing structure of the vehicle cannot meet the pedestrian leg protection regulations. This paper designs a thin-walled steel structure and applies it to the front-end structure of the vehicle. After collision simulation with a simplified finite element model of the leg, the pedestrian's tibial acceleration, knee joint shear displacement and knee joint bending angle are compared and analyzed. Pedestrian leg injury parameters, the results show that thin-walled steel structure is more suitable for giving full play to the energy absorption effect in an environment with insufficient energy absorption space than foam energy absorption structure.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Method for near-net forming of a sand mold with digital flexible extrusion technology

引用

China Foundry 2017年第6期14卷 492-497页

作者： Shuai Zhang Zhong-de Shan Jing-wei Ji Zhao-xian Gu State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing 100044 China

In order to further improve the precision forming efficiency of a sand mold digital patternless casting and reduce the amount of sand mold cutting, a method for near-net forming of the sand mold with digital flexible extrusion technology was put forward. The theory, optimization algorithm and technology for sand mold nearnet forming were studied. Experimental results show that the sand mold forming efficiency can be increased by 34%, and the molding sand can be reduced by 44%. The method for near-net forming of a sand mold with digital flexible extrusion technology can effectively promote the application of digital patternless casting technology in the mass production of castings and thus greatly improves the efficiency and automation of sand mold manufacturing.

关键词： patternless casting technology near-net forming sand mold flexible extrusion technology geometric packing

来源：评论

学校读者我要写书评

暂无评论

Wear Mechanism and Prediction Model of Polycrystalline Diamond Tool in Milling Sand Mould

引用

Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 2018年第17期54卷 124-132页

作者： Shan, Zhongde Zhu, Fuxian State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science Technology Beijing100044 China School of Materials Engineering Jiangsu University of Technology Changzhou213001 China

For the advantage of patternless casting technology in mould making, the wear mechanism of PCD tool is studied and the prediction models of wear ratio are built based on the sand mould milling experiments with polycrystalline diamond (PCD) tool. The micro phase morphology of wear zone of PCD tool is observed by scanning electron microscopy, from which the change rule with the processing time and the wear mechanism are studied. The results show that the high frequency scrape and impact of the raised sand particles on the flank during the sand milling process lead to the cleavage fracture of diamond particles and the scraping of the bonding material among the PCD particles in the surface of the tool, which cause the diamond particles to fall off. Furthermore, the microscopic defects in the tool and the "hard spots" in the sand mould cause the cutter micro chipping. Based on support vector machine (SVM) regression analysis algorithm, Matlab is used to compile the regression program of the ratio of wear to milling volume to build the prediction model of wear ratio based on the orthogonal experimental results. The influence of process parameters on tool wear ratio are predicted with the model, which can provide the basis for the wear control of the tool with high efficiency processing sand mould. © 2018 Journal of Mechanical Engineering.

关键词： Regression analysis

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：