Xie W.,FAW CAR Co. |
Yuan S.,Harbin Institute of Technology
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2016
Experiment and numerical simulation are conducted to study the deformation characters and thickness distribution during seamed tube hydroforming to disclose the effect of weld-seam on forming and the generation mechanism of defects. Meanwhile, the comprehensive effect of weld is analyzed in different processes. The results show that the weld-seam is one of the most predilection sites of bursting defects due to the weld plastic drop when bending and leads to wrinkling and bursting in the subsequent process even if the weld-seam is far away from the corner zone. The wall thickness is mainly affected by bending and hydroforming calibration processes. The preforming process has little effect on the thickness. Deformation amount of weld-seam is bigger than that of other zones for its high flow stress, as a result which induces a slight nouniformity thickness distribution. Therefore, the weld-seam is the important factors leading to defects during seamed tube hydroforming. It is helpful to minimize the effects of poor plasticity for weld-seam and prevent bursting defects by placing the weld-seam in the position of slight compressing deformation area. © 2016 Journal of Mechanical Engineering.
Xie W.-C.,Harbin Institute of Technology |
Xie W.-C.,FAW Car Co. |
Yuan S.-J.,Harbin Institute of Technology
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2017
In order to investigate the deformation behaviour of welded tubes during hydraulic bulging process, the hydraulic bulging tests of thin-walled welded low carbon steel tubes (STKM11A) were conducted on the tube hydroformability testing unit. The thickness distribution, profiles of bulging area and the strain distribution were all obtained. Results show that the thickness reduction of weld zone is just 2.4%-5.5% while its effective strain is just 0.05-0.10, which is very small and negligible compared with the parent material and means that just the geometric position of weld zone is changed with the continuous bulging. The thinnest points are located on the both sides of weld seam symmetrically and the angle between the thinnest point and weld seam is about 30°, at which the necking has been occurred. When the length of bulging area increases, the fracture pressure, the thickness reduction and the ultimate expansion ratio all decrease, and the profile of the bulging area gradually steps away from the elliptical model which is powerless for the ratio of length to diameter up to 2.0. Moreover, the strain state of the tube is transformed from biaxial tension to plane strain state with the increasing length of bulging area, on the basis of this the forming limit diagram of welded STKM11A steel tubes can be established. © 2017, Journal of Materials Engineering. All right reserved.
Teng B.-G.,Harbin Institute of Technology |
Yuan S.-J.,Harbin Institute of Technology |
Chen Z.-T.,University of New Brunswick |
Jin X.-R.,FAW Car Co.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2012
The Gurson-Tvergaard-Needleman model (GTN model) was employed to analyze bursting behavior in the hydroforming of stainless steel T-shape. A free-bulging test combined with simulation was conducted to determine the critical porosity and the failure porosity in GTN model. The effects of the forming pressure and the axial feeding on damage development were investigated and the influences of stress triaxiality and the plastic strain on porosity variation were also studied. The results show that a higher forming pressure or a less axial feeding will lead to bursting failure. The stresses of the top of protrusion are in bi-axial tension state, while the stresses of the side wall of main tube are in hoop tension state and axial compression state, respectively. The plastic strain has a more significant influence on the porosity than the stress triaxiality under the lower internal pressure; however, the stress triaxiality will govern the growth of porosity under the higher internal pressure. The simulation results give a good agreement with the experimentally determined thickness, and the maximum thickness-thinning rate is about 36%. © 2012 The Nonferrous Metals Society of China.
Zhang M.,Jilin University |
Ren J.,Jilin University |
Zhou S.,FAW Car Co.
Qiche Gongcheng/Automotive Engineering | Year: 2016
On the basis of traditional methods, another measuring method for load ratio of vehicle body, i.e. interface force method is adopted to analyze the load ratio of a semi-monocoque body of a coach and modify its structure with increasing its load ratio as objective. Firstly it is found by the calculation of the strain energy density of structure that the body structure bears lesser load, its material insufficiently fulfills its function, and different rings bear different loads with the load ratio of rings in rear position higher than those in front position. Then based on the results of strain energy density analysis, some parts in under-frame, such as front and rear longitudinal rails and luggage compartment are selected to be optimized, with their section size and thickness taken as optimization variables, and the performances of structure modified (strength, bending stiffness, torsional stiffness and low-order modal frequencies) are analyzed and compared with those of original one. The results show that the outcome of optimization is satisfactory, demonstrating that interface force method can accurately calculate the loads borne by each ring structure of body and their distribution, guiding the direction of targeted structure modification and optimization. The load ratio indicator adopted can effectively judge the material distribution between the body and under-frame of vehicle and can be an indicator of measuring the rationality of coach structure and an objective of optimization. © 2016, Society of Automotive Engineers of China. All right reserved.
Fu Y.,Hunan University |
Wang J.,FAW CAR Co. |
Hu S.,Hunan University
Acta Mechanica | Year: 2014
Based on the first-order shear deformation beam theory, considering geometric nonlinearity, the governing equations for symmetric laminated composite beams subjected to uniform temperature rise are derived by using Hamilton's principle, and then three solving methods are presented to deal with it. By introducing an auxiliary function, which is shown in method one, the governing equations are reduced to be a single fourth-order integral- differential equation, and the exact solutions for the thermal buckling and postbuckling of symmetric laminated composite beams with combination of in-plane immovable simply supported and clamped boundary conditions are presented for the first time. On the basis of the results given in the method one, the explicit solutions for the thermal buckling and postbuckling of the beams are presented by giving accurate displacement functions (method two) and Ritz method (method three), respectively. Then, the effects of the transverse shear effects and boundary conditions on the thermal buckling and postbuckling of the beams are qualitatively discussed. What is more, a preliminary discussion on the probability and difference of extending the giving methods to the higher-order shear deformation beam theory with various boundary conditions is conducted. In the numerical examples, the good agreements between the present results and existing solutions verify the validity and efficiency of the present analysis and numerical results. And then the symmetric cross-ply laminated composite beam (0/90/0) is taken as an example to numerically evaluate the effects of the length-to-thickness ratio, beam theories, and boundary conditions on the thermal buckling and postbuckling of symmetric laminated composite beams. Some meaningful conclusions have been drawn. © 2013 Springer-Verlag Wien.
Zhang W.,CAS Shenyang Institute of Metal Research |
Sun D.,Jilin University |
Han L.,Volkswagen AG |
Li Y.,FAW Car Co.
Materials and Design | Year: 2015
A novel resistance spot welding method of dissimilar materials of 6008-T66 aluminium alloy and H220YD galvanised high strength steel was presented, and the morphology of welding electrodes was designed optimally. Macrostructure, microstructure and mechanical property of the welded joints obtained with optimised electrodes were studied. Numerical simulation of current density distribution and temperature field during welding was also performed. The optimised electrodes were a planar circular tip electrode with tip diameter of 10mm on the steel side and a spherical tip electrode with spherical diameter of 70mm on the aluminium alloy side. The welded joint obtained with optimised electrodes could be regarded as a special welded-brazed joint, and an intermetallic compound layer composed of Fe2Al5 and Fe4Al13 with maximum thickness of about 4.0μm was formed at the aluminium/steel interface in the welded joint. Tensile shear load up to 5.4kN was achieved for the welded joint obtained with optimised electrodes. Current density distribution during welding with optimised electrodes was more homogeneous than that with F type electrodes. Furthermore, interfacial temperature in the welded joint during welding with optimised electrodes (about 915°C) was lower than that with F type electrodes (about 985°C). © 2015 Elsevier Ltd.
Tan G.,Jilin University |
Wang D.,Jilin University |
Chen S.,Jilin University |
Song J.,FAW CAR Co.
SAE Technical Papers | Year: 2012
In contrast to functionality and reliability, which are more and more assumed to be a natural and necessary condition of any vehicle, the performance of Noise, Vibration and Harshness (NVH) now belongs to those features which play an essential role for the customer's purchasing decision. Sound design and vehicle interior noise control are essential parts of NVH. One tool of the NVH solution toolbox is Active Noise Control (ANC). ANC technology aims to cancel unwanted noise by generating an "anti-noise" with equal amplitude and opposite phase. Owing to the fact that human hearing has selective sensitivity for different critical bands, a new control strategy of ANC, which selectively controls the noise of specific bandwidths according to the result of specific loudness and retains the part of noise created by the normal running of facilities, trying to attenuate the unwanted and unacceptable noise, has been proposed in this paper. The new ANC system based on Filtered X Least Mean Square (FXLMS) algorithm takes the human auditory characteristics into account by incorporating a specific loudness filter set in the two input paths of controller respectively, and is employed in a detail case by numerical simulation. Simulation results illustrate it possible to achieve these aims that the noise of specific bandwidths is attenuated and sound qualities are improved to some extent. Copyright © 2012 SAE International.
Liu D.-L.,FAW Car Co. |
Qu Y.-B.,Harbin Institute of Technology
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2012
This paper focuses on the application of Hilbert-Huang Transform approach to harmonic analysis in power system. Compared with FFT and wavelet transform, HHT has advantages such as being good at analyzing non-stationary signal, good adaptive ability and inexistent choice of basis functions. However, the approach has end effects and mode mixing which limit its application and development. In this paper, RBF-point symmetric extension method is proposed to improve the end effects. And for the mode mixing, notch filter is used to preprocess the signal, and then HHT analysis is conducted. Simulation indicates that the improved HHT not only effectively suppresses the end effects, but also ensures good accuracy when fundamental frequency energy of the signal is large.
Wang Y.-C.,FAW Car Co. |
Wang L.-F.,FAW Car Co. |
Xu Z.-Y.,FAW Car Co. |
Yang G.,FAW Car Co.
Proceedings - 2010 IEEE 17th International Conference on Industrial Engineering and Engineering Management, IE and EM2010 | Year: 2010
IE still has a powerful vitality after the financial crises times. The architecture model of IE and economic growth mode transformation is built on the basis of studying the connotation of IE and economic growth mode, and the inner operating mechanism is discussed. Take FAW Car for example, the application and innovation of IE in the economic growth mode transformation of autonomous vehicle enterprises are discussed by using lots of practical cases, then the experience and regular of IE application are put forward. © 2010 IEEE.
Xie W.-C.,FAW Car Co.
Cailiao Kexue yu Gongyi/Material Science and Technology | Year: 2013
In order to improve the wall thickness distribution and tube-forming limits of hydroformed asymmetrical tubular components, the internal pressure during feeding and axial feeding which affect the wrinkling and bursting of hydroforming were studied in this work. The hydroforming process was simulated by using Dynaform software and the experiments were done at the same time. Wrinkling occurred when the pressure was below 32 MPa during feeding and bursting occurred when the pressure was above 42 MPa. It was suitable for pre-forming between 34~42 MPa. With left axial feeding of 42 mm and right axial feeding of 22 mm, an asymmetrical tubular component was formed successfully at the maximum pressure of 126 MPa. The maximum expanding and thinning of this component were 70.75% and 27.12% respectively. It is shown that a uniform wall thickness distribution and high forming limits could be obtained through the proper pre-forming. The shape and quantity of wrinkles and the match of internal pressure and feeding was optimized to attain a uniform wall thickness distribution and a higher forming limits.