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Comparative study on forming limit prediction of AA7075-T6 sheet with M−K model and Lou−Huh criterion

Transactions of Nonferrous Metals Society of China 2020年第6期30卷 1463-1477页

作者： Guo-jiang DONG Zhi-wei CHEN Zhuo-yun YANG Bo-cheng FAN Hebei Key Laboratory of Special Delivery Equipment Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of Education of China Yanshan UniversityQinhuangdao 066004China

In order to effectively predict the fracture of AA7075-T6 sheet, the forming limit curves of AA7075-T6 high-strength sheet were drawn according to Morciniak Kuczyski (M K) model and Lou Huh criterion, respectively. The errors between the predicted values of the two theoretical prediction models and experimental values were calculated by error analysis. The forming limit curves were verified by the punch stretch test to evaluate the prediction accuracy of M K model and Lou Huh criterion. The error analysis results show that the mean error of Lou Huh criterion with the optimal parameters for all tensile specimens is 25.04%, while the mean error of M K model for all tensile specimens is 74.24%. The prediction accuracy of Lou Huh criterion in predicting the fracture of AA7075-T6 sheet is higher. The punch stretch test results show that the forming limit curve drawn by Lou Huh criterion can effectively predict the fracture of AA7075-T6 sheet, but the prediction accuracy of M K model is relatively poor.

关键词： ductile fracture criterion M K model forming limit diagram AA7075-T6 sheet

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Microstructure, Tensile Properties and Heat-Resistant Properties of Selective Laser Melted Almgsczr Alloy Under Long-Term Aging Treatment

SSRN

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SSRN 2022年

作者： Bi, Jiang Liu, Lei Chen, Guang Jia, Xiangdong Chen, Xi Xia, Hongbo Li, Xiaopeng Starostenkov, Mikhail Dmitrievich Han, Bing Dong, Guojiang Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China College of Mechanical and Electrical Engineering Nanjing Forestry University Nanjing210037 China State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin150001 China School of Mechanical Engineering Yangzhou University Yangzhou225127 China College of Material Science and Engineering Nanjing University of Science and Technology Nanjing210094 China General Physics Department Altai State Technical University Leninst. 46 Barnaul656099 Russia Institute of Intelligent Manufacturing Guangdong Academy of Sciences Guangdong Key Laboratory of Modern Control Technology Guangzhou510070 China

Selective laser melting (SLM)-processed AlMgScZr alloy has aroused widespread interest in the aerospace industry due to its outstanding comprehensive performance and excellent heat resistant properties. The fine grain morphology and diffusely distributed thermally stable precipitates of this alloy are believed to play a critical role in its high-temperature performance. By modifying the alloy with Sc and Zr, nano-sized Al3(Sc, Zr) phases can act as heterogeneous nucleating particles to effectively promote grain refining and precipitate strengthening. In this paper, a Sc and Zr-modified Al-Mg alloy was printed by SLM, and the long-term aging treatments in the temperature range of 275-350 ℃ with a constant holding time of 144 h were performed to investigate the heat-resistant properties of this alloy. Under as-fabricated condition, the AlMgScZr alloy exhibited high tensile strengths of 487.7 MPa and 393.9 MPa at temperatures of 25 ℃ and 200 ℃, respectively. When the alloy was aged at 300 ℃ for 144 h, its grain morphology was almost unchanged, but its tensile strength and elongation at room temperature reached 501.3 MPa and 31.3 %, respectively. This SLM-fabricated AlMgScZr alloy is expected to replace some titanium alloy components for medium-temperature applications. © 2022, The Authors. All rights reserved.

关键词： Aluminum alloys

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Study on the Health Condition Monitoring Method of Hydraulic Pump Based on Convolutional Neural Network

Study on the Health Condition Monitoring Method of Hydraulic...

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International Conference on Measuring technology and Mechatronics Automation, ICMTMA

作者： Sun Shaowu Zhang Sheng Jiang Wanlu Li Zhenbao Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Qinhuangdao China

ISBN: (数字)9781728170817

ISBN: (纸本)9781728170824

Aiming at the different health states of hydraulic pumps, this paper proposes to use the convolutional neural network to classify and identify the time-frequency images of different volumetric efficiency of hydraulic pumps to realize the health status monitoring of hydraulic pumps. After collecting the vibration signal data of the hydraulic pump, the time-frequency map is formed by short-time Fourier transform, wavelet transform, and Wigner-Will distribution, and then the generated time-frequency map is divided into a training set and a test set, in which the former is used to train the convolutional neural network and the latter is used to verify the recognition result. Finally, it is proved that the convolutional neural network can well identify the different health states of the hydraulic pump, and the recognition rate reaches 99%.

关键词：

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Force Analysis of the Overconstrained Mechanisms Based on Equivalent Stiffness Considering Limb Axial Deformation

Research Square

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Research Square 2021年

作者： Guo, Jinwei Zhao, Yongsheng Chen, Bo Zhang, Guoxing Xu, Yundou Yao, Jiantao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of National Education Yanshan University Qinhuangdao066004 China

Considering the limb axial deformation, taking typical 2SS+P and 7-SS passive overconstrained mechanisms, 2SPS+P and 7-SPS active overconstrained mechanisms, and 2SPS+P and 7-SPS passive-input overconstrained mechanisms as examples, a new force analysis method based on the idea of equivalent stiffness is proposed. The equivalent stiffness matrix of passive overconstrained mechanism is derived by combining the force balance and deformation compatibility equations with consideration of axial elastic limb deformations. The relationship between the constraint wrench magnitudes and the external force, limb stiffness is established. The equivalent stiffness matrix of active overconstrained mechanism is derived by combining the force balance and displacement compatibility equations. Here, the relationship between the magnitudes of the actuated wrenches and the external force, limb stiffness is investigated. Combining with the equivalent stiffness of the passive overconstrained mechanism, an analytical relationship between the actuated forces of passive-input overconstrained mechanism and the output displacement, limb stiffness is explored. Finally, adaptability of the equivalent stiffness to overconstrained mechanisms is discussed, and the effect of the limb stiffness on overconstrained mechanisms force distribution is revealed. © 2021, CC BY.

关键词： Stiffness

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Research on active pressurized forced lubrication deep drawing process and evaluation of lubrication effect

Research Square

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Research Square 2021年

作者： Chen, Duan Zhao, Changcai Chen, Xiaoyi Li, Haoyang Zhang, Xin Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Ministry of Education of China Qinhuangdao Hebei066004 China College of Mechanical Engineering Yanshan University Qinhuangdao Hebei066004 China

Friction and lubrication are important parameters that affect the quality of sheet metal forming, excellent lubrication condition and less harmful friction can reduce local thinning of sheet metal, delay fracture and improve surface quality. Aiming at the poor friction conditions and difficult lubrication in the flange area during deep drawing, an active pressurized forced lubrication deep drawing(FLDD) process was proposed in this paper. A hydraulic system was employed to flush high pressure lubricating oil into the contact gap between die and sheet in the flange area. The high pressure hydrostatic oil film in the contact gap can reduce the real contact area and improve the lubrication condition effectively. The equipment is simple, the cost is low, and lubricating oil pressure can be measured and controlled. Under the conditions of 20kN, 35kN and 50kN blank holder force(BHF), FLDD test of box parts was carried out with 5MPa and 9MPa pressure water-based lubricating oil. The horizontal comparison experiment was conducted with common lubricating media such as polyethylene film(PE film), high-purity molybdenum disulfide particles, vegetable oil and water-based lubricating oil under the same process conditions. Lubrication effect was evaluated by obtaining test data. Test results illustrated that the lubrication effect of high-purity molybdenum disulfide particles was the best and that of vegetable oil was the worst. The lubrication effect of water-based mineral lubricant was significantly improved after pressurization. The maximum forming height was increased by 17.97%, the maximum forming force was reduced by 8.9%, the maximum wall thickness thinning rate was reduced by 7%, and the lubrication effect of 9MPa pressure was superior to that of 5MPa. Although there is still a certain shortfall with special lubricating media such as high-purity molybdenum disulfide, FLDD process has definite application value in improving production environment, pollution control and aut

关键词： Sulfur compounds

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WITHDRAWN: Characterization of the hot deformation behaviour of powder metallurgy Ti–22Al–25Nb alloy by using 3D processing maps

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Intermetallics 2020年

作者： Jia, Jianbo Yang, Zhigang Peng, Weijin Dong, Tiantian Xu, Yan Liu, Hailiang Luo, Junting Education Ministry Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Qinhuangdao066004 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066004 China

Powder metallurgy (PM) Ti–22Al–25Nb (at.%) alloy was prepared by spark plasma sintering under the conditions of 950 °C/80 MPa/10 min. Isothermal unidirectional compression experiments of the PM Ti–22Al–25Nb alloy were completed on the Gleeble-3500 thermal–mechanical simulator at temperature and strain rate ranges of 920 °C–1100 °C and 0.001–10s−1, respectively, and a total height reduction of 50%. The flow characteristics were described by the establishment of constitutive models belonging to the (α2+β/B2+O) three-phase (920 °C–980 °C) and (α2+B2) two-phase (1010 °C–1070 °C) regions. The three-dimensional (3D) hot processing maps regarding temperatures, strain rates and strains were obtained. The optimum processing parameters (temperature and strain rate) were determined. The microstructures of the deformed specimens under various conditions were analyzed to characterize the corresponding deformation mechanisms. Moreover, electron backscattered diffraction (EBSD) measurements were employed to study the mechanisms of DRX. It was determined that the deformation activation energies of the PM alloy corresponding to the (α2+β/B2+O) phase and (α2+B2) phase regions were 763.969 and 685.587 kJ mol−1, respectively. In addition, the results proved that the proposed 3D hot processing maps could reveal the deformation mechanism and microstructural evolution of the PM Ti–22Al–25Nb alloy during hot processing. The main softening mechanisms in the stability regions were dynamic recrystallization (DRX) and lamellar dynamic globularization. The deformation mechanisms of the unstable domains identified from the 3D instability maps were adiabatic shear bands and flow localization. © 2020 Elsevier Ltd

关键词： Spark plasma sintering

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Dynamics of Passive-input Overconstrained Deployable Antenna Mechanisms Composed of 3RR-3RRR Tetrahedron Units

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Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 2020年第5期56卷 181-191页

作者： Liu, Wenlan Xu, Yundou Guo, Jinwei Yao, Jiantao Zhao, Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao066004 China

The dynamic model of a passive-input overconstrained deployable antenna mechanism composed of 3RR-3RRR tetrahedron units is established, and the effects of the number, stiffness and initial compression angle of driving elements (i.e., torsion springs) on the motion of mechanism are analyzed. Based on the structural characteristics and spatial coordinate transformation formulas the relationships between the positions of the centroid of each component and the independent deployment angle of the mechanism are deduced, and then the analytical expressions of velocities of all components are obtained. The movements of all components are divided into translation motion, fixed-axis rotation, plane motion and compound motion according to the characteristic of the degree of freedom (DOF) of the mechanism. For the sake of dynamic analysis of the passive-input overconstrained mechanism, the composite motion of components is further decomposed into plane motion and translation motion along the normal direction of the plane. The dynamic models of the passive-input overconstrained deployable mechanism 3RR-3RRR and its combined mechanism 3(3RR-3RRR)-3RRR-3RRR are built by using Lagrange method. The relationships between the stiffness of torsion springs and the independent deployable angle of the mechanisms are obtained, and the influence of the stiffness and number of torsion springs on the deployable motion of the mechanisms is analyzed. The simulation model of 3(3RR-3RRR)-3RRR-3RRR mechanism is established by Adams software. The simulation is carried out by adding torsion springs with different numbers and stiffness. In addition, the effect of initial compression angle of torsion springs on the deployable motion of the mechanism is discussed. The simulation results verify the correctness of theoretical analyses. The results can provide theoretical guidance for the coordinated control of passive-input overconstrained deployable antenna mechanisms composed of 3RR-3RRR tetrahedron u

关键词： Stiffness

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Design and analysis of a truss deployable antenna mechanism based on a 3UU-3URU unit

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Chinese Journal of Aeronautics 2019年第12期32卷 2743-2754页

作者： Yundou XU Jinwei GUO Luyao GUO Wenlan LIU Jiantao YAO Yongsheng ZHAO Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao 066004China College of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China

Space deployable structures with large calibers, high accuracy, and large folding ratios are indispensable equipment in the aerospace field. Given that the single-DOF 3 RR-3 RRR deployable unit cannot be fully folded, this study proposes a 3 UU-3 URU deployable unit with two kinds of DOF: folding movement and orientation adjustment. First, based on the G-K formula, the DOF of the 3 UU-3 URU unit is analyzed. Then, the 3 UU-3 URU unit is used to construct a deployable truss antenna with a curved surface, and the DOF of the whole deployable antenna containing multiple 3 UU-3 URU units is calculated. The structural design of a deployable antenna with two loops is carried out with specific parameters and geometric relations. Next, a DOF simulation of a basic combination unit composed of three 3 UU-3 URU units is performed. Finally, a prototype of the basic combination unit is manufactured, and the DOF of the mechanism is experimentally verified.

关键词： Basic combination unit Degree of freedom(DOF) Deployable truss antenna Simulation analysis Structural design

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Kinematic Characteristics and Dynamics Analysis of a Double-ring Truss Deployable Antenna Mechanism

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Binggong Xuebao/Acta Armamentarii 2020年第4期41卷 810-821页

作者： Han, Bo Xu, Yundou Yao, Jiantao Zheng, Dong Li, Yongjie Zhao, Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University QinhuangdaoHebei066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University QinhuangdaoHebei066004 China

A double-ring truss deployable antenna mechanism, which is used as the support and deployment mechanism for large-diameter space-borne antenna, is proposed to improve the stiffness of the single-ring truss deployable antenna with large diameter. The structural decomposition of double-ring truss deployable antenna mechanism is conducted, the screw constraint topology graph of the closed-loop deployable mechanism unit is drawn, and the degree of freedom (DOF) of the mechanism is analyzed. The analyzed result shows that the double-ring truss deployable mechanism has only one DOF. The screw velocity of each component in the mechanism is analyzed based on screw theory, the angular velocity and centroid linear velocity of each component are obtained through vector operation, and the Jacobian matrixes are also obtained. Furthermore, the screw accelerations of the components in the mechanism are derived based on the screw derivative, and the angular acceleration and centroid linear acceleration of each component in the double-ring truss mechanism are obtained. A dynamic model of the double-ring truss mechanism is established based on Newton-Euler equation and virtual work principle, and the numerical calculation and simulation verification are carried out. The research results show that the theoretical analysis is correct. The proposed double-ring truss deployable antenna mechanism has a simple structure, and can be smoothly deployed with only one input drive, the kinematic and dynamic analysis method based on screw theory used in this paper has a clear physical meaning, the analysis process is relatively stylized and is easy to program. © 2020, Editorial Board of Acta Armamentarii. All right reserved.

关键词： Screws

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Parameter calibration of anisotropic GTN model and forming limit for S600 aluminum alloy sheet

Engineering Research Express

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Engineering Research Express 2025年第2期7卷

作者： Chen, Xiaohua Wang, Zhanshan Zhang, Xuejian Dong, Guojiang Yang, Zhuoyun Yu, Shuang Wang, Yang Yang, Yiru Department of Mechanical and Electrical Engineering Suzhou Vocational Institute of Industrial Technology Suzhou215104 China National-Local Joint Engineering Research Center for Advanced Manufacturing Forming Technology and Equipment Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

High strength aluminum alloy sheet has obvious anisotropic characteristics and negligible necking in plastic deformation, making its fracture judgment in forming process more difficult than other metals. Taking S600 aluminum alloy sheet as the research object, a coupling model of anisotropic yield criterion and micro-damage theory namely Yld2000-GTN model was established, and its VUMAT subroutine was embedded into ABAQUS software in this study. The proposed model can improve the accuracy of fracture prediction for high-strength aluminum alloy sheet during plastic deformation. Uniaxial tension test and shear test were used to adjust the anisotropic parameters in Yld2000-GTN model. Uniaxial tension test was also employed to adjust damage parameters in Yld2000-GTN model with a new proposed method named sectional type parameter identification method (STPIM) basing on response surface method (RSM) and objective function method (OFM). However, these damage parameters could not accurately simulate the Force-Stroke curves of other notched samples with the highest error up to 18.94%. To correct this error, the relationship between stress triaxiality and damage parameters was further investigated and used to modify damage parameters. Taking the modified parameters into simulation, the prediction error of Force-Stroke curve for all notched samples was reduced to less than 5%. Finally, the theoretical forming limit diagram (FLD) of S600 aluminum alloy sheet was established by the modified parameters, and its accuracy was verified by the bulging test with hemispherical punch. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.

关键词： ABAQUS

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