Papers by Keyword: Bending

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Authors: Ming Chang, Juti Rani Deka, Chia Hung Lin, Chin Chung Chung
Abstract: One-dimensional (1D) nanostructure such as nanowires (NWs), nanobelts and nanorods have attracted tremendous attention in recent years due to their exceptional micro-structural properties and novel potential applications. In the present investigation, titania (TiO2) nanowires are synthesized by microwave hydrothermal process (MHP) treating TiO2 nano powder with NaOH inside a microwave oven for 5h at 210°C and 350W. The mechanical properties of as synthesized TiO2 nanowires are determined by bending it with a nanomanipulator inside a scanning electron microscope (SEM). Young’s moduli of the nanowires are measured to be approximately 11.870.923GPa.
Authors: Xia Jin, Shi Hong Lu
Abstract: Bending of the aluminum alloy is one of the processes frequently applied during manufacture of aircraft sheet metal. The bending operation involves springback, which is defined as elastic recovery of the part during unloading. In manufacturing industry, it is still a practical and difficult problem to predict the final geometry of the part after springback and to design appropriate tools in order to compensate for springback. In this study, 3D commercially available finite element analysis (FEA) software-MARC is used to analyse bending and springback of different aluminium materials (LY12CZ) with different thickness. The amount of springback, total equivalent plastic strains and equivalent von mises stresses are obtained. Moreover, the relation between bent angle and springback angle, R/t ratio and springback angle are presented and discussed in detail.The comparison results of FEA result and experiment data indicate that the FEM (finite element analysis method) simulation is a power tool for the highly accurate prediction of springback behavior in sheet metal bending.
Authors: Myung Hyun Kim, Chung In Ha, Sung Won Kang, Jeong Hwan Kim, Jae Myung Lee
Abstract: Fatigue strength assessments with two types of load carrying fillet weldment under out-of-plane bending load have been carried out by using both hot spot stress and structural stress methods. Basis for the derivation of structural stress method is discussed in detail. Finite element analyses using shell elements models have been performed for the fatigue strength assessment of weldments. As a result of the fatigue strength evaluation for load carrying transverse fillet weldment, hot spot stress method is found to be consistent with structural stress method as well as measurement. Hot spot stress, however, estimated for the load carrying longitudinal fillet weldment exhibit large variation with respect to mesh size and element type while the calculated structural stress for the longitudinal fillet weldment is relatively independent of mesh size. The fatigue life estimation according to structural stress has been introduced with the master S-N curve.
Authors: Cosmin Mihai Miriţoiu, Dumitru Bolcu, Marius Marinel Stănescu, Rosca Vîlcu, Dan Ilincioiu
Abstract: There were built some new original composite sandwich bars with polypropylene honeycomb core and the exterior layers of the bars were made of epoxy resin reinforced with steel wire mesh. For these composite bars, there were determined the stiffness by using two different experimental methods: variant 1- using the Walter-Bai testing machine and variant 2- using the eigenfrequency of the first eigenmode. The errors between these two methods were determined. In the next stage of the paper, some metallic beams, equivalent from the stiffness point of view with the composite ones, were considered. Comparisons between them, from the mass per unit length point of view, were made.
Authors: Xiao Jun Liu, Yuan Feng Wu, Xing Rong Chu, Qiang Wei, Qian Jin Fu, Qing Gao Ji, Chun Feng Zhao
Abstract: High-strength steel has a promising application due to vehicle mass reduction requirement while the high springback of forming and welding processes limits its application. Bending control and welding processes of ZQS700Z welded tube for automotive drive shaft are studied and the key processing technology is obtained. Weld microstructure analysis and flattening/flaring tests are performed and good performances are obtained.
Authors: Jian Qiang Wang, Zhong Hua Wang, Lu Sheng Zhu, Jian Yang, Zi Wen Cheng
Abstract: With high volume and flexible automated production line becoming the future trend of automobile welding line, the modular gripper, as the role of the robot tool, is finding increasing application. This article concluded the deformation formula by detecting bending and torsion deformation of aluminum profile in tests and also provided guidance and rationale for designers.
Authors: Bernd Engel, Christopher Kuhnhen, Christian Mathes, Christopher Heftrich, Peter Frohn, Sebastian Groth
Abstract: During the bending of tubes, specific geometric deviations from the desired shape geometry occur. These deformations comprise cross-sectional deformation, wall-thinning of the outer arc and wall-thickening of the inner arc. During the bending of parts with small bend factors, geometric deviations on the inner arc in form of waves and wrinkles may arise as other typical quality criteria. A quantitative evaluation of those deviations has yet to be defined. Currently, only an instruction for measuring the height of the wrinkles at the inner arc according to DIN EN 13480-4 is known. In this standard, only the two highest wrinkles and the valley in between are included. The characteristics of the wrinkle, especially the flank angle and the rise of deformation are disregarded, although they are responsible for the failure of the bent part. Tool damages can also occur. A development of an evaluation factor to assess deformations in the bow area for bent parts is presented in this paper. In addition, it will be possible to quantify geometric deviations in the bow area. By using the newly developed evaluation factor for geometrical deformations in the bow area, the determination of the quality of the bent part should become more reproducible.
Authors: Hong Zhang, Hai Qun Que, Huan Ding
Abstract: This paper firstly introduces a new general solution constructed by double trigonometric cosine series with supplementary terms for the bending and vibration analysis of orthotropic rectangular plates with four free edges on the Winkler foundation subjected to arbitrary vertical force. The general solution, which is fourth-order continuously differentiable with less undetermined coefficients, can be used to solve the bending and vibration problems of orthotropic rectangular plates on the Winkler foundation with various physical parameters requiring no classification and superposition. This makes the bending and vibration analysis of orthotropic rectangular plates with four free edges on the Winkler foundation more unified, simplified and regulated. This paper also gives a Series of analytical example to prove that the method is feasible.
Authors: Juan Liao, Chi Zhou, Feng Ruan, Yin Zhu
Abstract: The dimensional inaccuracy caused by springback is a major problem for most stamping applications. One of the most promising ways to solve this problem is to compensate it by means of appropriate tool shape modifications. In this paper, a new springback compensation method is introduced. A coefficient of curvature correction, which reflects the deviation of the experiment data and the analytical calculation data, is also proposed to redesign the tooling shape. This method was applied to a two-dimensional wavy-shaped part forming case for verification. The experiment results demonstrated that this method is efficient.
Authors: Zhe Li, Khoon Siong Ng, Tie Cheng Wu, Xiao Ping Li
Abstract: Measuring deep brain neural activities with a microelectrode is of greatest importance in uncovering the mechanism of various brain disorders. In this operation, a microelectrode needs to be accurately inserted into deep the brain. However, a microelectrode of high flexibility would bend at encountering a layer of tough tissue during insertion, which would lead to deflection and impaired targeting accuracy. To deal with this problem, a rotational insertion method has been developed in this paper for deflection-free insertion. Rotation helps generate a dynamic anti-bending force to prevent buckling, and this force becomes larger with the increase of rotational speed. Thus, by controlling the rotational speed at which insertion is carried out, deflection-free insertion of a microelectrode deep into brain can be realized. The effectiveness of this method has been experimentally confirmed.
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