Papers by Author: Xiao Hang Liu

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Authors: Hao Bin Tian, Xiao Hang Liu, Jian Ping Lin
Abstract: Tailor-welded blanks (TWB) have been widely used in automobile industry. In this paper, expanding experiments are carried out for tailor-welded blanks both with curved seams and straight seams, and the formability of tailor-welded blanks with curved seams has been studied and compared with tailor-welded blanks with straight seams. The effects of thickness ratios and seam radius on the formability of tailor-welded blanks with curved seams and straight seams are deduced, separately. In the end, the relationships between the shapes of welding seams and forming heights, and relationships between the thickness ratios and forming heights are given, which are valued to the designers and processers of tailor-welded blanks.
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Authors: Wen Jing Yuan, Hao Bin Tian, Xiao Hang Liu, Xiao Song Wang, Shi Jian Yuan
Abstract: Firstly, the geometry condition of useful wrinkles during the hydroforming of double-cone tube was given. Then the stress condition of useful wrinkles was given by formula between the parameters of wrinkles shape at the end of axial feeding and internal pressure, hoop stress and axial stress. The analytical results were compared with the FEM analysis and experiments results. The results show that the useful wrinkles must meet both the geometry condition and the stress condition. The geometry condition of useful wrinkles is that the area of arbitrary length of wrinkles is a little smaller than the area of corresponding die cavity. The stress condition of useful wrinkles is that shape parameter G is not smaller than the radius R at the top of middle wrinkle. That means the increment of thickness strain dεt is positive and no thickness thinning will occur during the calibration. When the wrinkles didn’t match geometry condition, the dead wrinkles or bursting will take place. And when the wrinkles didn’t match stress condition, the bursting at top of middle wrinkle will occur during the calibration.
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Authors: Cai Ping Liang, Fang Fang Sun, Xiao Hang Liu
Abstract: Single sided resistance spot welding (SSRSW) developed from resistance spot welding (RSW) is a feasible plan to join vehicle structure to closed-form tube and is increasingly used in automobile manufacturing. A ring spot weld can be formed between the two workpieces during this process. The weld strength is critical to the performance of vehicle. The mechanical property of the ring nugget, however, is lack of attention. In this study, a simulation model of workpieces with ring nugget for tensile-shear test was established and the stress and strain distributions around the weld were researched in detail. It was found that the maximum stress is generally concentrated at the out edge around the ring nugget. The failure region, however, may be in the heat affected zone (HAZ) instead of in the place of maximum stress, which should be judged by stress failure criteria (SFC) in the model. In addition, the tensile stress and shear stress on the surface of the lower sheet and upper tube were illustrated.
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Authors: Qing Sheng Wang, Xiao Hang Liu, Xin Lei Zhu, Zhu Shi Rao
Abstract: Sound source localization is always of great value in many engineering applications. In recent years, studies on orientation mechanisms of the auditory systems and research of bionic structures of subminiature creatures, especially of the parasitoid fly Ormia Ochracea which has a remarkable ability to detect the direction of the incident sound stimulus despite of its tiny body size, may provide preferable solutions for the miniaturization of acoustic localization structure. In this paper, the bionic acoustic sensing device are set up and taken as the research object to find feasible orientation mechanisms, and the dynamics of the bionic mechanical coupled diaphragms are analyzed. These works provide the basis for the manufacture of experimental acoustic sensing device. In the last part of this paper, experiments on bionic acoustic sensing device are conducted after the test system has been established. The measured data and the analyses based on the measured data demonstrate that the modeling methods and theoretical study in this paper are correct.
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Authors: Hao Bin Tian, Xiao Hang Liu, Zhong Tu Yu
Abstract: The control arms, as an important part of automobile chassises, are using Aluminum alloy in more and more cases instead of steel. The ball joint sealing of control arms is a key process to chassises assembly and the sealing quality directly determine the lifespan of steering systems of automobiles. In this paper, based on the aluminum control arms, revolving-reveting processes for ball joint sealing of control arms are studied through finite element methods and experiments, and the effects of housing shape on the quality of ball joint sealing are also studied. The results show that the sealing quality for ball joint is related to the housing shape, and a better sealing quality can be achieved when the housing has a sloped edge, and verified by the experiments, which will provide elementary technical support to the ball joint sealing of automobile control arms. Keywords: Ball joint sealing; Revolving-reveting technology; Aluminium control arm.
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Authors: Hao Bin Tian, Xiao Hang Liu, Jian Ping Lin, Xian Ping Liu
Abstract: The forming of tailor-welded blank is an important technology to body light weighting. While it is difficult to predict the forming limits of tailor welded blanks with different base materials or thickness. For the expanding experiments, an analytical method to predict forming limit height of tailor-welded blanks is established based on the deformation characteristic and plastic theory, and verified by simulation results. This method is not only provided a path to predict forming limit of tailor welded blanks but also provided references to the design of tailor weld parts.
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Authors: Xiao Hang Liu, Mike Daniels, Bez Shirvani
Abstract: For reasons of cost and weight, light gauge sheet is used wherever possible for metal fabrications. In sheet metal forming the process is to gather the metal into defined areas. The pulley forming process is no exception and is achieved by superimposing axial loads on top of radial loads using a pressure-controlled tailstock. Whilst the headstock-mounted tooling is fixed, that part held on the tailstock can be powered axially under controlled pressure. This pressure is governed by the width of the workpiece which changes during the forming process. Experiments have been designed to provide an understanding of the pulley forming process and to verify numerical models. The latter has been taken the form of finite element simulations to enable prediction of metal flow, tool forces and potential sources of defects and failures. There are three objectives for conducting the experiments which have been investigated in this paper: 1. providing data to define the movements of the forming tools for the finite element model, including displacements and velocities, 2. understanding the effects of the pulley forming operation on the flow of material, and 3. validating the finite element model.
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