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Progress of crystal plasticity theory and simulations
ZHANG Hai-ming;XU Shuai;LI Qian;LIU Jia-ru;SHANG Xiao-qing;DONG Xiang-huai;CUI Zhen-shan;The development history,constitutive models,and homogenization schemes of crystal plasticity theory with large deformation were reviewed. Several theoretical achievements and typical applications of crystal plasticity were outlined. The theories basis,advantages and disadvantages of both phenomenological and physically based crystal plasticity models were compared and analyzed in terms of flow models,work hardening models,and the evolution of state variables. The characteristics and applications of both mean-field and full-field crystal plasticity models were illustrated. The typical applications of crystal plasticity simulations were introduced from the aspects of anisotropy,texture evolution,non-uniform plastic deformation,formability,size effect,damage and fracture behavior,hot deformation and microstructure evolution,and virtual testing etc. And future development trends in this field were pointed out.
Present situation and prospects of stamping process planning for automobile pane ls
ZHENG Jing-qiao HUANG Yong WANG Yi-lin LI Zhi-gang (State Key Laboratory of Plastic Forming Simulation and Die & Mould Technology, Huazhong University of Science & Technology, Wuhan 430074)Stamping process planning of automobile panel are th e foundation of the die's design and manufacturing, and the key point for panel's forming satisfactorily. The present process studies on automobile panel forming such as forming ability analysis, process planning, process particular designs a nd the actuality computer aided process planning are discussed, and the trends i n press process planning for automobile panels are also analyzed in this paper.
Review on application and fabrication of shark skin bionic structure
LIU Bao-sheng;WU Wei;ZENG Yuan-song;Beijing Aeronautical Manufacturing Technology Research Institute;The riblet structure of shark skin is proved to significantly effect drag reduction.The bionic riblet structure is widely applied in industry,such as aviation,naval vessels,automotives,pipe transportation and wind power generation.The fabrication of the bionic riblet structures focuses on two styles:simplified riblet structure and shark placoid scales directly replication.As to the former style,the typical technologies of micro-riblet rolling,diamond profile grinding,femtosecond laser ablation are reviewed.And the technologies of micro-thermal pressing,solidification,micro-casting,mirco/nano-rolling and soft lithography are also reviewed for the latter style.Finally,the suggestions on the riblet structure fabricating are presented.
The application and development of advanced shot peen forming technologies
ZENG Yuan-song HUANG Xia LI Zhi-qiang(Beijing Aeronautic Manufacturing Technology Research Institute,Beijing 100024 China)Some advanced shot peen forming(SPF) technologies such as the pre-stress SPF technology,the numerical SPF technology and several new type of SPF technologies including the double-sided simultaneous SPF,the Laser SPF,the ultrasonic SPF and the water-jet cavitation shotless peening technology,have been reviewed in this paper.The principle and the current developing situation of these advanced technologies have been analyzed,which will have the important signification on the research and developement of SPF technology.
State-of-the-arts and prospectives of manufacturing and application of titanium alloy tube in aviation industry
JIANG Zhi-qiang YANG He ZHAN Mei(School of Materials Science and Engineering,State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072 China)XU Xu-dong LI Guang-jun(Chengdu Aircraft Industry(Group) Corporation Ltd,Chengdu 610092 China)The state-of-the-arts of the research on manufacturing,bending forming,end processing and joint technologies of titanium alloy tube are reviewed.The current development,existing problems and solutions of some key projects are analyzed.Finally,suggestion on research,development and application of titanium alloy tube in Chinese aircrafts is proposed.
Major breakthrough and progress in metal forming technology and equipment of China in the last 30 years
LIN Zhong-qin;HUANG Qing-xue;YUAN Shi-jian;ZHAO Guo-qun;HUA Lin;YI You-ping;ZHAN Mei;LI Shu-hui;LIU Wei;WANG Bao-yu;CHEN Jun;WANG Tao;LI Hong-wei;HUANG Liang;HE Zhu-bin;ZHONG Jue;In the last 30 years since 1994, remarkable achievements have been achieved in China in the field of metal forming technologies and equipments, under the strong traction of national great demands. A series of the largest equipments in the world were developed, the three major technical breakthroughs were realized and the largest scale of research teams were built up. The overall level of metal forming technologies in China has entered the ranking of advanced countries in the world, with several unit technologies and equipments reaching the international leading level. Eight of the most representative achievements were selected, and the major breakthrough in plastic engineering theory and technology and outstanding contributions to the development of national great equipment were introduced. The gap of metal forming technologies between China and the world-top level was analyzed. Finally, the five development trends named“three ‘ultra' and two ‘high'” in the development of metal forming technologies in China were prospected.
Research progress of the multi-scale modeling of heterogeneous deformation for hard-to-deform material based on crystal plasticity
ZHAN Mei;LI Hong-wei;SUN Xin-xin;HUANG Dong;WU Chuan;WANG Xu;CHEN Shan-shan;Crystal plasticity modeling and its analysis algorithms for the heterogeneous deformation prediction were analyzed and reviewed,and the key difficulties and solutions of the crystal plasticity modeling considering the multi-phase heterogeneity characteristic and grain boundary inhomogeneity characteristic were discussed. The cellular automata modeling for the microstructure evolution was analyzed and reviewed,and the key difficulties and solutions of the coupled modeling between the crystal plasticity and cellular automata considering the interaction between heterogeneous deformation and microstructural evolution were demonstrated. Moreover,thoughts of the coupling multi-scale models based on macroscale finite element method,mesoscale crystal plasticity finite element method and microscale cellular automata,and applications of these models on the multi-scale response prediction of the forming of titanium complex bulkhead components were discussed. Finally,the existing problems in current multi-scale model was analyzed,and an outlook of multi-scale modeling was given.
Tensile fracture test and numerical simulation of Q235 steel
WANG Yu-kai;ZHAO Jian-xin;The tensile fracture behavior of Q235 steel(cold-rolled,hot-rolled) at low strain rates(0.0001-0.01 s-1) was investigated by using INSTRON tester.The tensile fracture process of cold-rolled Q235 steel and hot-rolled Q235 steel was numerically simulated by Abaqus.The results show that under low strain rates,with the strain rate increases,the yield stress and peak stress of the steel increase,but the yield stress is more sensitive to the change of strain rate.For Q235 steel,the tensile mechanical properties of cold-rolled steel and hot-rolled steel are different.The strength of cold-rolled steel is higher than that of hot-rolled steel,but its ductility is lower than that of hot-rolled steel,and the peak stress and reduction of area are more sensitive to the change of strain rate.The Johnson-Cook constitutive model parameters of cold-rolled Q235 steel and hot-rolled Q235 steel were obtained based on test data.The rationality and reliability of the description of the model on tensile mechanical behavior of steel were verified.
Study and development on the application of ABAQUS in the sheet metal rapid forming simulation based on Python
WU Xiang-dong LIU Zhi-gang WAN Min WANG Wen-ping HUANG Lin(Beihang University,Department of Aircraft Manufacturing,Beijing 100191 China)Python scripting language was used for pre-processing module of ABAQUS for secondary development,the role of Python script and the call process was discussed in the ABAQUS secondary development,the development of ideas and general steps was put forward.Through the Python script for the sheet metal rapid forming simulation,an effective solution was proposed to allow users creating true loading rate amplitude according actual press parameters.The results showed that the procedure was friendly and feasible.Through a typical Stamping example,compared and analyzed the node slip velocity curve and translational velocity curve.It proved the truth that the true loading rate simulating by Finite element software can reflect the slip velocity between sheet metal and die,providing the basis for the follow-up analysis in actual testing.
Introduction of sheet metal hot-forming
XU Wei-li1 AI Jian3 LUO Ai-hui4(Baoshan Iron & Steel Co.,LTD.,R&D Center,Shanghai 201900 China)GUAN Shu-rong2(Baoteel Metal Co.,Ltd,Shanghai 200120 China)Blank hot forming is a new technology which is realized by heating the advanced high strength steel to Austenitic phase,quick stamping,and quenching in die during press holding to meet the required cooling speed.By this new forming technology,the phase of the parts can be changed to martensite,and the strength of the parts can be about 1500MPa.In this paper,Key equipments,key technology,advantage and disadvantage of blank hot forming are introduced,and the application status and trends is proposed.