Papers by Keyword: Torsion

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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.
273
Authors: Giovanni Meneghetti, Mauro Ricotta, L. Negrisolo, Bruno Atzori
Abstract: In previous papers, the energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, has been successfully applied to correlate experimental data generated from push-pull, stress- or strain-controlled fatigue tests on AISI 304 L stainless steel plain and notched specimens. In this paper the fatigue behaviour of AISI 304 L un-notched bars under fully-reversed axial or torsional loading was investigated. By using the Q parameter it was found that the experimental data collapse into the same energy-based scatter band previously determined with the push-pull tests. The results found in the present contribution are meant to be specific for the material investigated.
453
Authors: M. Lopez-Pedrosa, Bradley P. Wynne, Mark W. Rainforth
Abstract: The effects of strain path reversal on the microstructure in AA5052 have been studied using high resolution EBSD. Deformation was carried out using two equal steps of forward/forward (F/F) or forward/reverse (F/R) torsion at a temperature of 300°C and strain rate of 1s-1 to a total strain of 0.5. In both cases the deformation microstructure in the majority of grains analysed consisted of microband arrays clustering at specific angles to the macroscopic deformation axes. For the F/F condition microbands clustered around -20° and +45° to the maximum principle stress direction, whilst for the F/R condition significantly more spread in microband angle was observed. This suggests that the microbands formed in the forward deformation have or are dissolving and any new microbands formed are related to the deformation conditions of the final strain path. This leads to the conclusion that instantaneous deformation mode determines the orientation of new microbands formed whilst a non-linear strain path history influences the range of misorientation angle in the material through the dissociation of previously formed microbands and the formation of new microbands at the new straining condition, leading to a lower level of misorientation angle. Analysis of material subjected to static annealing at 400°C for 1 hour appears to correspond with these observations as the F/F material was completely recrystallised with a fine grain structure whilst the F/R material had no major signs of recrystallisation.
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Authors: M. Lopez-Pedrosa, Bradley P. Wynne, Mark W. Rainforth, P. Cizek
Abstract: The effects of strain path reversal on the macroscopic orientation of microbands in AA5052 have been studied using high resolution electron backscatter diffraction. Deformation was carried using two equal steps of forward/forward or forward/reverse torsion at a temperature of 300°C and strain rate of 1s-1 to a total equivalent tensile strain of 0.5. In both cases microbands were found in the majority of grains examined with many having more than one set. The microbands appear to cluster at specific angles to the macroscopic deformation. For the forward/forward condition microbands clustered around -20° and +45° to the maximum principle stress direction and at ± 30-35° to the principal strain direction. For the forward/reverse condition significantly more spread in microband angle was observed though peaks were visible at ±35° with respect to principal stress direction and at -40° and +30° with respect to the principal strain direction of the reverse torsion. This suggests the microbands formed in the forward deformation have or are dissolving and any new microbands formed are related to the deformation conditions of the final strain path.
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Authors: Bradley P. Wynne, O. Hernandez-Silva, M. Lopez-Pedrosa, Mark W. Rainforth
Abstract: The effects of strain path reversal, using forward and reverse torsion, on the microstructure evolution in the aluminium alloy AA5052 have been studied using high resolution electron backscatter diffraction. Deformation was carried using two equal steps of forward/forward or forward/reverse torsion at a temperature of 300°C and strain rate of 1s-1 to a total equivalent tensile strain of 0.5. Sections of the as-deformed gauge lengths of both test specimens were then annealed at 400°C for 1 hour in a salt bath in order to investigate their subsequent recrystallisation response. In both strain path histories the deformation substructure in the grains analysed consisted of microband arrays within an equiaxed dislocation cell structure. The material subjected to forward/forward deformation did, however, have a slightly greater number of low angle boundaries, i.e. boundaries < 15° misorientation, whilst the forward/reverse material had some grains containing little evidence of substructure. On annealing both materials had significantly reduced levels of low angle boundaries but only the forward/forward material had an increased number of high angle boundaries and a reduced grain size, indicating recrystallisation had only occurred in this material. This would suggest that the deformation microstructure within the forward/forward condition was sufficient to initiate and maintain recrystallisation whilst the microstructure produced by the forward/reverse test contained insufficient nuclei or internal energy to produce a recrystallised material within 1 hour. Further work is now required at different annealing times in order to determine if the major effect of strain path is on retarding nucleation, growth or both.
407
Authors: O.U. Orie
Abstract: This paper determined the torsional strength of steel reinforcements used in the construction industry in Nigeria and compares their Modulus of Rigidity with available standards. Fifteen test specimens were examined from the reinforcing steel of various sizes ranging from 8mm to 20mm diameter which were sourced randomly. The samples were tested with the Torsion Testing Machine until failure. The initial parameters such as gauge length and diameter were considered before the application of torque. The failure torque for the 8mm, 10mm, 12mm, 16mm and 20mm steel reinforcements obtained from the test are 15Nm, 28.81Nm, 77.09Nm, 191.89Nm and 368.99Nm respectively. The result showed that the torsional strength of reinforcement available in the construction industry is below the standard modulus of rigidity of 21000N/mm2 by about 15%.
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Authors: Hai Jun Zhou, Hong Hong Huang, Hua Zhang
Abstract: An experimental study on mechanical behavior of superelastic NiTi shape memory alloy (SMA) bar subjected to torsion was made. The SMA specimen was in round bar shape, material phase was austenite and stress mode was torsion. The test was carried out by applying repeated cyclic uniform torsional load. Strain rate, strain amplitude and number of cycles were considered as test parameters. The test was described and analyzed in terms of three fundamental mechanical quantities: secant stiffness, energy loss per unit weight and equivalent damping. The test results show that SMA bar subjected to torsion, have great potential for application in seismic devices due to their considerable superelasticity and stable cyclic behaviors.
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Authors: Nasir Shafiq, Muhammad Imran, Ibrisam Akbar
Abstract: Eccentric loads are very common in structures due to building configuration. Unequal slab length, circular ramp, large cantilevers are very common in modern architecture. The RC beams in previous studies were tested under the three and four point uniform loads. Therefore, a simple testing setup was arranged to understand the behaviour of RC beam under eccentric load applied at mid span. In this study the single point load applied eccentrically on RC beam. The beams were tested at different eccentricity and compared with control beam tested under the uniform load or zero eccentricity. Results have shown a drastically reduced crack load up to 54% compared to control beam as the eccentricity increased. However, small changed in ultimate load carrying capacity was observed up to 60mm eccentricity. Eccentric load caused biaxial bending due to high concentration of load on one side of beam, which change failure mode of RC beam from ductile to brittle.
339
Authors: Yan Mei Li, Qing Hua Chen, Ying Jun Chen, Wen Gang Wu
Abstract: In this paper, the folded-beam torsion MEMS mirror that meets a set of specified constraints was developed. An optimization algorithm that we newly adopted in the RCS(restricted competition selection) GA(genetic algorithm) could overcome some difficulties in single-search algorithms. Moreover, by the proposed method, the designer’s experience, and view and judgment could be reflected effectively.
135
Authors: C.D. Naiju, K. Annamalai, Prakash Nikhil, Babu Bevin
Abstract: This study is aimed at carrying out a finite element analysis on a roll cage of a vehicle used for student competitions around the world. The design process was carried out using a CAD package and analysis was done using finite element analysis software, ANSYS. Impact test was carried out on the roll cage under different conditions and the effect on the structural members are studied and discussed. The results are very much helpful and assure that the car is in safe condition in case of a crash or accident. Finite Element Analysis (FEA) is also carried out with the frame against torsional loading. Two different materials were considered for the analysis. The results of displacement of frame, nodal solution, element solution and bending moment are discussed.
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