NetWork
Optimization of residual stress in TC4 titanium alloy blades based on full-process simulation
XIE Dan;CHEN Bang;HUANG Tong-zhu;HE Hao-lin;OUYANG Qiu-yue;DU Chang-liang;XU Wu-jiao;To address the issue of difficult-to-control residual stress in the first-stage rotor blades of aero-engine compressors throughout the full preparation process, full-process finite element calculations of TC4 titanium alloy blades based on the Simufact platform were conducted. The calculations include triple upsetting, pre-forging, final forging, trimming, sizing, annealing, and the transportation process between each step, obtaining the residual stress variation trends of the blades at each preparation stage. The residual stresses at three characteristic locations—the blade body, the dovetail and their connection—were measured in the forged finished blades using the holedrilling method and compared with the full process finite element results, verifying the accuracy of the established calculation model. By quantitatively analyzing the residual stress changes at each preparation stage, it was determined that the final forging is the primary stage of residual stress accumulation, while annealing is the main stage for its reduction. The influences of key factors during final forging and annealing, such as forging speed, forging temperature and annealing temperature on residual stress were investigated, and related process parameters were optimized through orthogonal experiments. The results indicate that with the increase of the final forging speed, the residual stress of the forging decreases; increasing the forging temperature causes the final residual stress to first increase and then decrease; increasing the annealing temperature promotes residual stress release, although the impact of β-phase precipitation on properties must be considered. Orthogonal experiments show that the influence of each parameter on residual stress follows the order: annealing temperature > forging temperature > forging speed. The optimal process combination is the forging temperature of 958 ℃, the forging speed of 160 mm·s-1, and the annealing temperature of 730 ℃.
Forward design and optimization of intermediate billet for rolling of profiled ring based on integration of flow-strain-temperature fields
WEI Ke;YUAN Shuai;RAN Xing;ZHU Ming-yu;FU Xu-kai;FENG Yan-cheng;YANG Jin;XU Dong;WANG Yu-feng;To meet the demands of precise manufacturing of high-performance complex-section rings in the aerospace field, a forward design and optimization method for the intermediate ring billet in the rolling process of TC4 titanium alloy C-section profiled rings was proposed, based on integration of flow-strain-temperature fields. Grounded in the theoretical competition behavior between diameter expansion and cross-sectional profile forming during ring rolling, the dimensional constraints for the intermediate billet that ensure complete crosssectional filling(corresponding to the flow field) were deduced forward. Subsequently, key geometric parameters influencing the ring billet volume distribution were taken as design variables, and the uniformity of strain and temperature distribution in the ring after rolling was set as collaborative optimization objectives, thereby a synergistic design process integrating forward design and intelligent optimization was established. The results demonstrate that the established system— “flow field analytical constraints, coupled with strain~/temperature field surrogate models and multi-objective intelligent optimization” —can obtain an optimal intermediate billet that simultaneously enhances the uniformity of both strain and temperature fields under the condition of complete cross-sectional filling.
Simulation and process optimization of internal high-pressure forming for profiled tubes based on entropy weight comprehensive evaluation method
DONG You-gen;XU Xue-feng;CHEN Yue-hui;LEI Xiao-qiang;LIAO Hong-wei;FAN Yu-bin;To address the issues of low efficiency, uneven wall thickness and low film adhesion rate in traditional internal high-pressure forming(IHPF) of profiled tubes, a process parameter optimization method based on the entropy weight comprehensive evaluation method was proposed for IHPF of complex-section intake profiled tubes. First, a finite element model for IHPF was established for the profiled tubes with axis length of 812. 86 mm, diameter of Φ170 mm at the left-end section and perimeter of 516. 2 mm at the right-end section.Then, an orthogonal experiment was conducted using a five-factors and three-levels scheme to analyze the influence of various process parameters on the forming quality of the intake profiled tubes. Finally, the three quality indicators were transformed into a single optimization objective-comprehensive score via the comprehensive evaluation method. Through range analysis of the comprehensive scores, the optimized IHPF process parameters for the profiled tube were obtained. The optimal parameter combination is as follows: the internal pressure follows a initially rapid and then slow loading path; the axial feed follows a initially slow and then rapid loading path; the friction factor in feeding zone is 0. 06; the friction factor in transition zone is 0. 01; and the friction factor in forming zone is 0. 06. The reliability of the process optimization results was finally verified through IHPF experiments.
Optimization of forging process for aviation engine support rings oriented to mechanical performance enhancement
XIONG Xian-qing;LIU Can;SU Hai;WU Tao;XU Wu-jiao;To address the issue that the tensile strength and fatigue life of an aviation engine support ring made of 2618 aluminum alloy fail to meet the service requirements after hot working. Electron backscatter diffraction(EBSD) was employed to characterize three distinct microstructural zones appeared on cross section of the aluminum alloy support ring. Comparative analyses of grain morphology, average grain size, recrystallized fraction, grain orientation spread(GOS), and geometrically necessary dislocation(GND) density reveals pronounced differences in recrystallization degrees among the three distinct microstructural zones. The finite element model of the hot forging process of aluminum alloy support ring was established to simulate the distributions of equivalent strain, recrystallized fraction, and average grain size under the original forging process. The results indicate that the heterogeneous recrystallization across the cross section primarily originates from the non-uniform strain distribution during hot forging. An orthogonal experimental design with three factors and three levels, including initial billet temperature, die forging speed, and friction factor, was subsequently adopted to optimize the hot forging parameters of support ring combining with numerical simulation. EBSD characterization of the forged support ring cross section after process optimization was carried out again, and the grain microstructure in all zones was refined compared with the original process. Moreover, tensile properties and fatigue life tests for optimized support ring forging were carried out, and all the indexes meet the design requirements.
Study on key parameters affecting push-spin integrated bending forming of aluminum alloy thin-walled tubes with a 0. 8D bending radius
LIU Jie;FAN Yu-bin;XU Xue-feng;LIU Jie-song;XIAO Jie;ZENG Xiang;XIE Jun;To enhance the bending forming limit of 5A02 aluminum alloy thin-walled tubes with small bending radius, the influence of key parameters in push-spin integrated bending forming for Φ30 mm×1. 0 mm tube blanks with a bending radius of 0. 8D was investigated.Combining Abaqus finite element simulation with process experiments, the influence of tube blank feed rate V1, spin wheel speed V2,back pressure P and its loading path on forming quality were systematically investigated. The results indicate that reducing the tube blank feed rate V1 can effectively suppress inner wrinkling, when V1 decreases from 15 mm·s-1 to 3 mm·s-1, the inner wall thickening rate decreases by 5. 1%. Spin wheel speed V2 plays a crucial role in improving forming quality, compared to a fixed spinneret configuration,increasing V2 to 1. 5V1 reduces inner wall thickening rate by 8. 0% and extends the stick-out length by 107. 8%, however, further increases of V2 shows diminishing returns. The back pressure P requires precise control, the value below 70 MPa may cause non-adherence to the die and wrinkling, while values above 70 MPa exacerbate wall thickness non-uniformity and inhibit material elongation; based on this,an optimal process window is determined: under the back pressure P of 70 MPa, combined with the D loading path(where P undergoes linear change and reaches the maximum value at 3/4 of the tube blank stroke), high-quality bent tubes without defects can be produced.
Effect of interference amount on mechanical performance of CFRP bolted joints: Analysis and numerical simulation
ZHANG Jin-yu;WANG Meng-sheng;YANG Yong-tai;Focusing on interference amount as the core process parameter, its dual influence on both the static and fatigue performance of CFRP single-lap bolted joints was systematically explored. Through conducting quasi-static tension and tension-tension fatigue tests across four interference levels, the regulatory effects of interference amount on the yield load, failure mode and fatigue life of the joint structures were quantitatively analyzed. Test results indicate that the static strength increases monotonically with the increase of interference amount,while the fatigue life exhibits nonlinear response laws of increasing first and then decreasing, and reaches peak value with interference amount of 0. 6%. Furthermore, a three-dimensional progressive damage finite element model incorporating the interference assembly effect was developed. This model couples 3D Hashin failure criterion with residual stiffness/strength degradation models and constant life equation. The simulation results align well with test data, the fatigue life across all working conditions is accurately predicted, with the maximum error below 3. 6%, and the key failure morphologies such as matrix damage around the hole are successfully replicated.
Current research status of techniques for enhancing metal material plasticity induced by different energy fields
WANG Xin-yu;HUO Yuan-ming;WANG Zhi-jun;YAN Zhen-rong;HE Tao;FAN Xiao-guang;YU Wen-han;LI Zhi-wei;WANG Zhao-zhao;SUN Le-le;Electroplasticity, hydrogen-induced plasticity, ultrasonic technology, laser technology and pulsed magnetic field technology show great potential in improving the plasticity of metal materials. By precisely controlling processing parameters and treatment conditions,these advanced technologies can introduce local plastic deformation into metal materials, achieving shape and property control. They not only enhance the formability of metals but also effectively boost their mechanical properties, such as strength and ductility, with particular advantages in microstructure optimization. However, although these technologies show promising applications, these technologies face challenges like energy transmission efficiency, surface quality, processing efficiency, and equipment cost. Future research will focus on developing more efficient, reliable, and cost-effective processing technology to increase their practical value in metal plastic forming. By optimizing technical parameters and improving equipment performance, these advanced processing technologies are expected to be used in more industrial fields, supporting the efficient and sustainable development of manufacturing.
Finite element simulation and experimental study on high-speed impact hydroforming of aluminum alloy sheet based on split-Hopkinson pressure bar
LI Wang;ZHANG Tuan-wei;CHANG Hui;ZHAO Dan;MAO Zhou-zhu;WEI Hui-jie;JIAO Zhi-ming;WANG Zhi-hua;Aiming at the difficult forming problem of light alloy with poor ductility at room temperature, the experiment design of highspeed impact and high-speed impact hydroforming was carried out by using the split-Hopkinson pressure bar technology. Numerical simulation and experimental analysis were conducted on the high-speed impact and high-speed impact hydroforming processes of 5052 aluminum alloy to study the process of high-speed impact hydroforming and the influence of impact velocity and sheet thickness on the forming depth and effect. The results show that the simulation results are in good agreement with the experiment results, and the reliability of the simulation is verified. In the process of high-speed impact hydroforming of 5052 aluminum alloy sheet, there is a secondary loading phenomenon in the form of double impact bodies. Before the first shock wave reaches the peak, the sheet appears “flat bottom phenomenon”.When the reflected wave reaches a certain position, the sheet depth continues to increase. With the increase of impact velocity, the forming depth increases gradually. The increase of sheet forming thickness requires greater impact energy. Compared with high-speed impact forming, high-speed impact hydroforming has obvious advantages, which can not only improve the surface quality of formed parts, but also reduce the impact speed and energy with the same forming depth requirement.
Internal high-pressure forming process and deformation law of high-strength aluminum alloy frame longitudinal beam
SUN Kang;HU Zhi-li;LONG Qu-bo;PANG Qiu;To solve the problems of multiple forming processes, long production cycle, poor dimensional accuracy and low assembly accuracy in traditional high-strength steel material stamping welding of frame longitudinal beams, an internal high-pressure forming process for high-strength aluminum alloy frame longitudinal beam was proposed. Taking 7075 high-strength aluminum alloy as the material, the frame longitudinal beams were prepared through internal high-pressure forming, which can effectively shorten the production cycle and improve product dimensional accuracy. Based on Dynaform finite element software, simulation of high-pressure forming inside the frame longitudinal beam was conducted to study the influence of forming process parameters on forming quality and to analyze the filling behavior of the pipe wall in the transition fillet area of the rectangular section. The frame longitudinal beam was experimentally trialed, the overall size and wall thickness distribution were measured, and the uniaxial tensile tests on materials in different areas of the longitudinal beam were carried out. It is ultimately found that during the internal high-pressure forming process of the high-strength aluminum alloy frame longitudinal beam, the best forming effect is achieved with the axial feeding amount of 20 mm, the forming internal pressure of 60 MPa, and the shaping internal pressure of 130 MPa. For the transition fillet filling, the greater the pressure inside the pipe and the lower the friction factor, the better the filling effect. Finally, the longitudinal beam with the length of 2000 mm, width of 190 mm, height of 70 mm filling, transition radius of 25 mm, thinning rate of about 18%, yield strength of 480 MPa, tensile strength of 560 MPa is produced through experimental trial, and the overall performance consistency is good, the dimensional accuracy is higher, and the production cycle is shorter. It is indicated that the frame longitudinal beam produced by internal high-pressure forming of 7075 aluminum alloy can meet the needs of actual production.
Research on drawing process of continuous tube protective sheath for mineral insulated cables
WANG Shao-hua;SONG Hong-bing;ZHANG Wan-peng;ZHOU Chao;XIE Hang;XIAO Qun-xing;XING Yu-lin;WANG Xiao-gang;The drawing theoretical formula was verified by experiments and the establishment of BP neural networks, the development of the drawing process and the effect of the weld on the quality of the tube after drawing were studied. The experiment results show that for 304 stainless steel welded tube, the maximum diameter reduction rate in a single pass is 30. 4%, and the maximum elongation is 40%;the drawing force is positively correlated with influencing factors such as the diameter reduction rate and the length of the working belt, and the drawing speed has little effect on the drawing force. The grain orientation at the weld can be effectively improved through the drawing process, so that the tubes have better formability along the drawing direction. BP neural network training model was established to obtain the regression value R, which shows that the model has good predictability, thus verifying the feasibility of the model.