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Study and practice of decreasing residual stress with residual heat of casting

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China Foundry 2008年第3期5卷 186-189页

作者： Tong Siyi Liu Lin guangxi yuchai machinery company limited Yulin 537005 Guangxi China Shenyang Casting and Forging Industrial Co. Ltd. Shenyang 110025 Liaoning China

A new technique for reducing the residual stress within a casting by using of the residual heat in the casting is *** new technique has been applied by guangxi yuchai machinery company limited and the result shows remarkably *** casting’s residual stress can be reduced to less than 60 MPa while the saving in energy can be about 101.1 kW.h per ton of castings,as compared with traditional technique.

关键词： casting's residual heat foundry residual stress

Molecular structures and activity of organic depressants for marmatite,jamesonite and pyrite flotation

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1993-1999页

作者：陈建华李玉琼龙秋容 College of Resources and Metallurgy Guangxi University College of Chemistry and Chemical Engineering Guangxi University Design and Research Institute of Mining and Metallurgy Zijin Mining Group Limited Company

Ten kinds of organic depressants were used to investigate the depressing performance on marmatite and *** results show that the organic compounds only with single group of hydroxyl(-OH),carboxyl(-COOH) or amino(-NH2) in molecule are ineffective in depressing marmatite,jamesonite and *** combinations of these functional groups still cannot enhance the depressing ability of organic *** thioglycollic acid containing reductive functional group(-SH) has a good depressing performance for marmatite and *** presence of benzene ring in molecule can enhance the depressing *** functional group electronegativity,hydrophilic-hydrophobic indexes and frontier orbital of organic depressants were calculated,and the criterion for the depressing effect of organic depressants to sulphide minerals was proposed.

关键词： marmatite pyrite organic depressant frontier orbital

Reducing residual distortion of thin-plate weldments by rotating extrusion

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Journal of Central South University 2013年第4期20卷 859-865页

作者：李军杨建国方洪渊张文锋 State Key Laboratory of Advanced Welding and Joining (Harbin Institute of Technology) Zhejiang Yinlun machinery company limited

A new method named rotating extrusion was developed to mitigate residual distortion of thin-plate weldments. The basic principle and characteristic of rotating extrusion as well as an efficient rotating extrusion device were introduced. Systematic trials were conducted to investigate the influence of several technological parameters including the distance between the extrusion tool and welding torch, the pressure acting on weldment, the dimension of the extrusion tool and its rotational speed on distortion control effect. Experimental results show that, as for 2A12T4 aluminum alloy weldment with 2 mm in thickness, 150 mm in width and 350 mm in length, when appropriate technological parameters are adopted, rotating extrusion can reduce its buckling deflection to below 3% of the original value. Implementing rotating extrusion during welding with an extrusion tool more than 100 mm away from the welding torch may achieve better distortion mitigation effect.

关键词： welding distortion thin plate aluminum alloy rotating extrusion

Integration of a Nonlinear Vibration Absorber and Levitation Magnetoelectric Energy Harvester for Whole-Spacecraft Systems

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Acta Mechanica Solida Sinica 2019年第3期32卷 298-309页

作者： Ye-Wei Zhang Zhi-Wei Fang Shi-Lei Wang Zhi-Yu Ni Jian Zang Bo Fang College of Aerospace Engineering Shenyang Aerospace University Shenyang 110136 China Shanghai Prime machinery company limited Shanghai 200072 China

This paper presents a new device integrating a nonlinear vibration absorber with a levitation magnetoelectric energy harvester for whole-spacecraft systems. This device effectively reduces vibration and has a stronger energy harvesting capability than the existing systems. It harvests energy from a wide frequency range and has a high output voltage. The harvested energy is determined by magnetic field strength, excitation frequency, and resistive load. The change in the magnetic field strength has the least impact on the output voltage. The vibration reduction effects and harvested energy of the system are analyzed with an approximate analytical method that combines the harmonic balance approach and the pseudo-arclength continuation algorithm. The results of the Runge-Kutta method are nearly consistent with those of the approximate analytical method. Moreover, the effects of the excitation frequency, resistive load, and parameters of the nonlinear energy sink on the system vibration response and energy harvesting are analyzed.

关键词： Levitation magnetoelectric energy harvester Whole spacecraft Nonlinear energy sink Vibration reduction

A novel robust AE/MS source location method using optimized M-estimate consensus sample

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International Journal of Mining Science and Technology 2022年第4期32卷 779-791页

作者： Yichao Rui Zilong Zhou Xin Cai Riyan Lan Congcong Zhao School of Resources and Safety Engineering Central South UniversityChangsha 410083China guangxi Xinfazhan Communication Group company limited Nanning 530029China

Due to the complexity of the real engineering environment, the arrival measurement inevitably contains outliers and leads to serious location errors. In order to eliminate the influence of the outliers effectively,this paper proposes a novel robust AE/MS source localization method using optimized M-estimate consensus sample. First, a sample subset is selected from the entire arrival set to obtain fitting model and its parameters. Second, consensus set is determined by checking the arrivals with the fitting model instantiated by the estimated model parameters. Third, optimization process is performed to further optimize the consensus set. The above steps are iterated, and the final source coordinates are obtained by using all the elements in the optimal consensus set. The novel method is validated by a pencil-lead breaks experiment. The results indicate that the novel method has better location accuracy of less than 5 mm compared to existing methods, regardless of the presence or absence of outliers. With the increase of outlier scale and outlier ratio, the location result of the proposed method is always more stable and accurate than that of the existing methods. Mine blasting experiments further demonstrate that the new method holds good prospects for engineering applications.

关键词： Microseismic source Acoustic emission Source localization Outliers Consensus sample

Grouting diffusion of chemical fluid flow in soil with fractal characteristics

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Journal of Central South University 2017年第5期24卷 1190-1196页

作者： ZHOU Zi-long DU Xue-ming CHEN Zhao ZHAO Yun-long School of Resources and Safety Engineering Central South UniversityChangsha 410083China guangxi Double Elephant Construction limited Liability company Nanning 530029China

The chemical fluid property and the capillary structure of soil are important factors that affect grouting diffusion. Ignoring either factor will produce large errors in understanding the inherent laws of the diffusion process. Based on fractal geometry and the constitutive equation of Herschel-Bulkley fluid, an analytical model for Herschel-Bulkley fluid flowing in a porous geo-material with fractal characteristics is derived. The proposed model provides a theoretical basis for grouting design and helps to understand the chemical fluid flow in soil in real environments. The results indicate that the predictions from the proposed model show good consistency with the literature data and application results. Grouting pressure decreases with increasing diffusion distance. Under the condition that the chemical fluid flows the same distance, the grouting pressure undergoes almost no change at first and then decreases nonlinearly with increasing tortuosity dimension. With increasing rheological index, the pressure difference first decreases linearly, then presents a trend of nonlinear decrease, and then decreases linearly again. The pressure difference gradually increases with increasing viscosity and yield stress of the chemical fluid. The decreasing trend of the grouting pressure difference is non-linear and rapid for porosity Φ>0.4, while there is a linear and slow decrease in pressure difference for high porosity.

关键词： grouting diffusion Herschel-Bulkley fluid porous media fractal grouting pressure

Effect of secondary aging on microstructure and properties of cast Al-Cu-Mg alloy

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China Foundry 2023年第1期20卷 71-77页

作者： Rui-ming Su Yong-xin Jia Jian Xiao Guang-long Li Ying-dong Qu Rong-de Li School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Guizhou Yonghong Aviation machinery limited Liability company Guiyang 550009China

To obtain better comprehensive properties of cast Al-Cu-Mg alloys,the secondary aging(T6I6)process(including initial aging,interrupted aging and re-aging stages)was optimized by an orthogonal *** microstructures of the optimized Al-Cu-Mg alloy were observed by means of scanning electron microscopy and transmission electron microscopy,and the properties were investigated by hardness measurements,tensile tests,exfoliation corrosion tests,and intergranular corrosion *** show that the S phase andθ’phase simultaneously exist in the T6I6 treated *** increasing the temperature of the interrupted aging in the T6I6 process can improve the mechanical properties and corrosion resistance of Al-Cu-Mg *** optimal comprehensive properties(tensile strength of 443.6 MPa,hardness of 161.6 HV)of the alloy are obtained by initial aging at 180℃for 2 h,interrupted aging at 90℃for 30 min,and re-aging at 170℃for 4 h.

关键词： cast Al-Cu-Mg alloy secondary aging mechanical properties corrosion resistance strengthening phase

Fracture behavior and mechanism of highly fragmented steel cylindrical shell under explosive loading

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Defence Technology（防务技术） 2024年第6期36卷 122-132页

作者： Kang Wang Peng Chen Xingyun Sun Yufeng Liu Jiayu Meng Xiaoyuan Li Xiongwei Zheng Chuan Xiao Xi'an Modern Chemistry Research Institute Xi'an 710065China Shanxi Jiangyang Chemical company limited Taiyuan 030051China Central Iron&Steel Research Institute company limited Beijing 100081China China Research and Development Academy of machinery Equipment Beijing 100089China

An in-depth understanding of the fracture behavior and mechanism of metallic shells under internal explosive loading can help develop material designs for warheads and regulate the quantity and mass distribution of the fragments *** study investigated the fragmentation performance of a new high-carbon silicon-manganese(HCSiMn)steel cylindrical shell through fragment recovery *** with the conventional 45Cr steel shell,the number of small mass fragments produced by the HCSi Mn steel shell was significantly increased with a scale parameter of 0.57 g fitted by the Weibull distribution *** fragmentation process of the HCSi Mn shell exhibited more brittle tensile fracture characteristics,with the microcrack damage zone on the outer surface being the direct cause of its high *** the one hand,the doping of alloy elements resulted in grain refinement by forming metallographic structure of tempered sorbite,so that microscopic intergranular fracture reduces the characteristic mass of the fragments;on the other hand,the distribution of alloy carbides can exert a"pinning"effect on the substrate grains,causing more initial cracks to form and propagate along the brittle carbides,further improving the shell *** the killing power radius for light armored vehicles was slightly reduced by about 6%,the dense killing radius of HCSiMn steel projectile against personnel can be significantly increased by about 26%based on theoretical *** results provided an experimental basis for high fragmentation warhead design,and to some extent,revealed the correlation mechanism between metallographic structure and shell fragmentation.

关键词： Projectile fragmentation Fragment mass distribution Fracture mode Metallographic structure Damage power

Alkali Tolerance of Concrete Internal Curing Agent Based on Sodium Carboxymethyl Starch

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 82-90页

作者：陈梅花刘荣进 CHEN Ping JING Daiyan WAN Dandan FU Siyuan College of Materials Science and Engineering Guilin University of TechnologyGuilin 541004China guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building Materials Guilin 541004China guangxi Maibu New Material limited company Guilin 541004China

Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of *** alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw *** results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali *** water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is *** application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore *** compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.

关键词： alkali tolerance sodium carboxymethyl starch internal curing agent compressive strength