Time filter

Source Type

Ma Y.,Shanghai JiaoTong University | Chen Y.,Shanghai JiaoTong University | Li S.-H.,Shanghai JiaoTong University | Peng H.-L.,Shanghai Spaceflight Precision Machinery Institute
Suxing Gongcheng Xuebao/Journal of Plasticity Engineering | Year: 2016

At 500℃,the creep tests were carried out at three stress levels 0.3σ0.2500℃,0.4σ0.2500℃and 0.5σ0.2500℃ for TB2 titanium alloy solution-treated for 30min at 800℃,air-cooled to room temperature. The new creep constitutive equations were established based on classic creep constitutive equation and Garofalo creep constitutive equation. The constitutive parameters in three creep constitutive equations were obtained by using Origin to fit the creep experimental data. The new creep constitutive equations can well describe the creep behavior of TB2 titanium alloy at different stresses by comparing the experimental results and computed creep curves. © 2016, Editorial Board of Journal of Plasticity Engineering. All right reserved.


Zeng K.-H.,National University of Defense Technology | Li Z.-Q.,Shanghai Spaceflight Precision Machinery Institute | Liang S.-L.,National University of Defense Technology | Xiao L.,Shanghai Spaceflight Precision Machinery Institute | Ma Q.-S.,National University of Defense Technology
Key Engineering Materials | Year: 2017

Mullite matrix composites with laminated and stitched carbon fiber cloth preform as reinforcement were fabricated via the route of "infiltration-drying-heat treatment" using Al2O3-SiO2 sol as raw materials. Thermal properties from room temperature to 1673K of the composites were investigated. The coefficient of thermal expansion (CTE) increases first and then decreases, and reaches a maximum of 4.83×10-6K-1 at 1273K. As a result of the further sintering of matrix, the CTE is negative at above 1300°C. The specific heat capacity increases to the maximum of 1.547J·g-1·K-1 at 1473K and remains stable at above 1473K, with a minimum of 0.756J·g-1·K-1 at room temperature. The thermal diffusivity decreases from 1.1mm2·s-1 at room temperature to 0.707 mm2·s-1 at 973K as the temperature was elevated, and remains stable at above 973K. On the contrary, the thermal conductivity is improved with increasing temperature on the whole and varies from 1.859W·m-1·K-1 at room temperature to 2.325W·m-1·K-1 at 1473K. © 2017 Trans Tech Publications.


Qiu K.,Shanghai JiaoTong University | Bie Y.,Shanghai Spaceflight Precision Machinery Institute | Qin S.,Shanghai JiaoTong University | An Q.,Shanghai JiaoTong University | Chen M.,Shanghai JiaoTong University
Key Engineering Materials | Year: 2016

High strength carbon fiber reinforced polymers (CFRP) with unidirectional laminate structure have gradually developed into major materials in load-bearing aerospace components, and the cutting demand of CFRP is increasing. In this work, orthogonal cutting tests were conducted on T700 high-strength CFRP laminates to get the mechanistic force model of special cutting tools. Also cutting force coefficients were obtained when cutting T700 high-strength CFRP laminates under different fiber orientations. Experimental results showed that the lowest cutting force was obtained when fiber orientation was between 120° and 150°. © 2016 Trans Tech Publications, Switzerland.


Wen L.,Shanghai JiaoTong University | Yang C.,Shanghai Spaceflight Precision Machinery Institute | Niu Q.,Shanghai JiaoTong University | Ming W.,Shanghai JiaoTong University | Chen M.,Shanghai JiaoTong University
Key Engineering Materials | Year: 2016

Serrated chips were a universal phenomenon and it had a significant effect on cutting process. In this paper, single tooth dry cutting of TC11 titanium alloy were conducted on a five-axis CNC machine using Stellram milling cutter with a diameter of 32 mm. Both chip macroscopic morphology and microcosmic morphology of TC11 titanium alloy were studied in-depth examining the impact of cutting speed and feed rate to the serrated chips. The results showed that: with the increase of cutting speed, the chip morphology of titanium alloy TC4 experienced a change process from the hair bar to a "C" shape and then become a long strip. The critical cutting speed of TC11 for serrated chips was found at 80 m/min and the critical feed rate to form serrated chip was defined as 0.05mm/z. With the increasing of cutting speed, the extent of chip serration was significantly enhanced. Increasing cutting speed can decrease the feed rate to form serrated chips. © 2016 Trans Tech Publications, Switzerland.


Peng H.L.,Shanghai Spaceflight Precision Machinery Institute | Li Z.Q.,Shanghai Spaceflight Precision Machinery Institute | Cheng Q.L.,Shanghai Spaceflight Precision Machinery Institute | Yuan Y.,Shanghai Spaceflight Precision Machinery Institute | Li M.Z.,Jilin University
Applied Mechanics and Materials | Year: 2014

The finite element model of flexible clamp multi-point stretch forming(FCMPSF) was set up, and extensive contradistinctive analysis of forming limit and forming accuracy between FCMPSF and RCMPSF were done. The results show that under the same forming conditions, spherical part formed by FCMPSF is not easy to fracturing, dimpling and springback, and is easy to fit the die. The reason for this was analysed. The non-fracturing limited graph, the non-dimpling limited diagram and the average springback value of spherical parts formed by FCMPSF and RCMPSF were obtained. Finally, the forming experiment and error analysis of spherical part formed by FCMPSF were done, the results indicate that 3D parts with large transversal curvature can be shaped by FCMPSF and the forming quality was guaranteed. © (2014) Trans Tech Publications, Switzerland.


Yu Y.,Harbin Institute of Technology | Zhang W.,Harbin Institute of Technology | Dong W.,Shanghai Spaceflight Precision Machinery Institute | Han X.,Aerospace Research Institute of Materials And Processing Technology | And 3 more authors.
Materials and Design | Year: 2015

Heat treatment with different parameters were performed on the hot-hydrostatically extruded and swaged 3.5. vol.% TiBw/Ti6Al4V composites tubes. The results indicate that the primary α phase volume fraction decreases and transformed β phase correspondingly increases with increasing solution temperatures. The α. +. β phases will grow into coarse α phases when the aging temperature is higher than 600. °C. The hardness and ultimate tensile strength of the as-swaged TiBw/Ti6Al4V composite tubes increase with increasing quenching temperatures from 900 to 990. °C, while they decrease with increasing aging temperatures from 550 to 650. °C. A superior combination of ultimate tensile strength (1388. MPa) and elongation (6.1%) has been obtained by quenching at 960. °C and aging at 550. °C for 6. h. High temperature tensile tests at 400-600. °C show that the dominant failure modes at high temperatures also differ from those at room temperature. © 2015 Elsevier Ltd.


Wen L.,University of Science and Technology Beijing | Yuan Y.,Shanghai Spaceflight Precision Machinery Institute | Wang Y.,Harbin Institute of Technology | Jin Y.,University of Science and Technology Beijing
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2015

The pure and Fe-containing nanocrystalline layers were fabricated on the surface of 2024 Al alloy by surface mechanical attrition treatment (SMAT) using ceramic balls and steel balls, respectively. The friction and wear properties of 2024 Al alloy before and after SMAT were investigated by sliding against a GCr15 steel ball of 5 mm in diameter at a load of 1.5 N. The results demonstrate that the surface nanocrystalline layers with average grain sizes of 49.2 and 52.1 nm can be obtained by using ceramic balls and steel balls, respectively, when treated for 30 min. Moreover, a 5 μm thick surface layer containing Fe is also introduced into the Al nanocrystalline surface when treated using steel balls. The wear resistance of 2024 Al alloy is improved due to the combination of grain refinement, increased hardness and lubrication effect of iron-containing layer. Copyright © 2015, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.


Xu X.,Shanghai Spaceflight Precision Machinery Institute | Li J.,Harbin Institute of Technology
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | Year: 2014

To promote the defective craft in non-circular grinding NC system, a special NC system for non-circular grinding is presented based on CPAC. First, on the basis of piecewise cubic spline fitting as mathematical foundation, the cutter center coordinates of X-Y is calculated. Second, the importance of constant speed grinding is produced, and two algorithms based on constant length of arc interpolation are put forward to realize constant speed grinding. Third, the method of error measuring and compensation is given. Finally, integrated system is completed and applied to three-axis milling machine. The experiment proves that the system can meet the needs of non-circular grinding. ©, 2014, Harbin Institute of Technology. All right reserved.


Wang H.-D.,Shanghai Spaceflight Precision Machinery Institute | Luan Q.-L.,Zhejiang University | Chen Z.-W.,Zhejiang University | He H.-N.,Hangzhou ECON Science and Technology Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Through studying the control algorithm for multi-exciter PSD (power spectral density) replication vibration tests, an identification strategy for the frequency response matrix of a vibration test system based on partial coherence analysis was designed. For situations of singular points existing in a system frequency response matrix and the matrix being rectangular, different system decoupling algorithms were desgined based on the solutions to the matrix generalized inverse and its Moore-Penrose inverse with the minimum norm and least square methods. Aiming at the situation that the system APSD (auto-power spectral density) might be negative or zero in the traditional difference correction of the drive spectral control algorithm, an improved PSD equalization control strategy was designed by introducing a proportional RMS feedback correction algorithm. The algorithm could effectively avoid the APSD being negative and zero in the process of PSD equalization. The multi-exciter PSD replication vibration tests showed that the improved PSD equalization control strategy can achieve a reliable, high-precision control effect on a multi-exciter vibration system. ©, 2015, Chinese Vibration Engineering Society. All right reserved.


Dong W.-Q.,Shanghai Spaceflight Precision Machinery Institute | Zhang X.-L.,Shanghai Spaceflight Precision Machinery Institute
Suxing Gongcheng Xuebao/Journal of Plasticity Engineering | Year: 2014

The FLDs of the aerospace sheet metal materials of 1Cr18Ni9Ti stainless steel, 7A09, 5A06, 2A14, 2A12 aluminum alloy and TC4 titanium alloy are studied by the experiments. The FLD calculating models of 1Cr18Ni9Ti, 5A06, 2A14 and 2A12 are established based on the experimental data. The experimental study shows that the formability of 1Cr18Ni9Ti is much better than those of 5A06, 2A14 and 2A12 under room temperature, also the thickness of the sheet metal affects its forming limitation a lot. The thinner the sheet is, the lower of the forming limitation becomes. The formability of 7A09 aluminum alloy and TC4 titanium alloy are too bad to obtain their FLD under room temperature.

Loading Shanghai Spaceflight Precision Machinery Institute collaborators
Loading Shanghai Spaceflight Precision Machinery Institute collaborators