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Journal articles on the topic 'Torsion torque'
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1
Shen, Kongjian, Shui Wan, YL Mo, and Xiayuan Li. "A softened membrane model for prestressed concrete composite box girders with corrugated steel webs under pure torsion." Advances in Structural Engineering 22, no. 2 (August 3, 2018): 384–401. http://dx.doi.org/10.1177/1369433218788597.
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Torsion can be regarded as a principal factor in some cases, such as in curved girders and eccentrically loaded girders, when conducting the structural analysis of prestressed concrete composite box girders with corrugated steel webs. Recently, a rational model, called the softened membrane model for torsion, was proposed for the torsional analysis of reinforced concrete members; thereafter, this model was extended to prestressed concrete members under pure torsion and called softened membrane model for torsion prestressed concrete. This article presents a modified model, the softened membrane model for torsion prestressed concrete for prestressed concrete composite box girders with corrugated steel webs, to analyze full torsional behavior. To build the model, the softened membrane model for torsion in reinforced concrete members is first extended to perform the torsional analysis of prestressed concrete composite box girders with corrugated steel webs by incorporating the torsional contribution of corrugated steel webs. Afterward, the initial stresses and strains due to prestressing are considered to extend the softened membrane model for torsion to softened membrane model for torsion prestressed concrete for prestressed concrete composite box girders with corrugated steel webs by modifying the equilibrium equations, convergence criteria, and constitutive laws of materials. The modified model is validated by experimental data and is proven to be capable of predicting the overall torque–twist curve, especially the precracked branch and postcracked ascending branch. In addition, a comparison between the softened membrane model for torsion and softened membrane model for torsion prestressed concrete indicates that the torque values before and after concrete cracking will be overestimated and underestimated, respectively, without considering the effect of the initial stresses and strains. Finally, another comparison shows that the softened membrane model for torsion prestressed concrete is superior to the rotating-angle truss model for torsion in its ability to predict the precracked branch of the torque–twist curve.
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Ludwig, Oliver, Jens Kelm, and Sascha Hopp. "Impact of Quadriceps/Hamstrings Torque Ratio on Three-Dimensional Pelvic Posture and Clinical Pubic Symphysis Pain-Preliminary Results in Healthy Young Male Athletes." Applied Sciences 10, no. 15 (July 29, 2020): 5215. http://dx.doi.org/10.3390/app10155215.
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Pain in the pubic symphysis is of significance, especially in high-performance sports. Pelvic torsion, possibly caused by muscular imbalances, is discussed as a pathogenic mechanism. This study examined a possible interrelationship between the maximum torques of quadriceps femoris and hamstrings and the spatial positioning of the hemi-pelvises, as well as the tenderness to palpation of the pubic symphysis. The three-dimensional pelvic contour of 26 pain free adolescents (age 16.0 ± 0.8 years, weight 66.3 ± 9.9 kg, height 176.2 ± 6.0 cm) was registered by means of an 3D optical system and the torsion of both hemi-pelvises against each other was calculated based on a simplified geometrical model. Tenderness on palpation of the pubic symphysis was assessed by means of a visual analogue scale, and isometric torques of knee extensors and flexors were measured for both legs. The torque ratio between knee extensors and flexors was calculated for both sides, as was the crossed torque ratio between the two legs. On the basis of a MANOVA, possible significant differences in torques and torque ratios between subgroups with lower and higher pelvic torsion were analyzed. The crossed torque ratio (F = 19.55, p < 0.001, partial η2 = 0.453) and the tenderness to palpation of the pubic symphysis (F = 10.72, p = 0.003, partial η2 = 0.309) were significantly higher in the subgroup with higher pelvic torsion. The results indicate the crossed torque ratio of knee flexors and extensors as a potential biomechanical-pathogenic mechanism to be considered in the primary prevention and diagnosis of symphyseal pain.
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Aghili, Farhad, Martin Buehler, and John M. Hollerbach. "Sensing the Torque in a Robot’s Joints." Mechanical Engineering 120, no. 09 (September 1, 1998): 66–69. http://dx.doi.org/10.1115/1.1998-sep-2.
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This article describes design specifications of a new sensor that can accurately measure the torsion moment in a direct-drive robot, even in the presence of strong overhang, thrust forces, and bending moments. Introducing a torque sensor into a robot joint adds flexibility. Although torsional flexibility can be compensated for by sophisticated controllers, deflection in the other axes is more problematic. Consequently, another design criterion dictates high stiffness in non-torsional directions. The sensor design must optimize, and trade off among several conflicting design criteria. Also, many design iterations are required to arrive at a final design. Despite this complexity, it is possible to arrive at a novel basic sensor design. Thin-section rectangular bars experience high stress/ strain concentrations under torsion loads, which yield high sensitivity without sacrificing stiffness. This fact suggests that an appropriate structure should be primarily stressed by torsion. The team used the finite element analysis (FEA) capabilities of I-DEAS from Structural Dynamics Research Corp. to finalize the dimensions so that performance would be optimized. FEA was also used to select the location and proper size of the strain gauges.
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Hu, Shao Wei, and Ke Yu Zhao. "Experimental Research on Torsional Performance of Prestressed Composite Box Beam with Partial Shear Connection." Applied Mechanics and Materials 438-439 (October 2013): 658–62. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.658.
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In order to research torsional performance of prestressed steel-concrete composite box beam with different shear connection, this paper designed three prestressed steel-concrete composite box beams with different degree of shear connection, and studied the stress characteristics of prestressed composite beam under static torsion process load. The torsion behaviors of prestressed composite beam such as the steel strain, concrete flange strain, rebar strain, angle of torsion, deformation and failure patterns are analyzed on the base of the experimental results. It comes to a result that shear connectors have little impact on beams cracking torque, but ultimate torque of composite beams decreases along with the reduction of shear connection degree. When the shear connection degree is 0.5, the ultimate torque is reduced by about 15%.
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Ma, Jie, Lu Bai, and Michelle D. Wang. "Transcription Under Torsion." Science 340, no. 6140 (June 27, 2013): 1580–83. http://dx.doi.org/10.1126/science.1235441.
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In cells, RNA polymerase (RNAP) must transcribe supercoiled DNA, whose torsional state is constantly changing, but how RNAP deals with DNA supercoiling remains elusive. We report direct measurements of individual Escherichia coli RNAPs as they transcribed supercoiled DNA. We found that a resisting torque slowed RNAP and increased its pause frequency and duration. RNAP was able to generate 11 ± 4 piconewton-nanometers (mean ± standard deviation) of torque before stalling, an amount sufficient to melt DNA of arbitrary sequence and establish RNAP as a more potent torsional motor than previously known. A stalled RNAP was able to resume transcription upon torque relaxation, and transcribing RNAP was resilient to transient torque fluctuations. These results provide a quantitative framework for understanding how dynamic modification of DNA supercoiling regulates transcription.
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Song, Bao, Hui Wang, Weihua Cui, Hui Liu, and Tingshuai Yang. "Distributions of stress and deformation in a braided wire rope subjected to torsional loading." Journal of Strain Analysis for Engineering Design 54, no. 1 (September 20, 2018): 3–12. http://dx.doi.org/10.1177/0309324718800814.
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Braided wire rope is vital for stringing conductors with tension in overhead transmission lines. Its structure and characteristics determine the safety and reliability of the stringing construction. Torque generated in this process can cause an uneven stress distribution, ultimately causing the wire rope to fail. This study analyzes distributions of stress and deformation in braided wire rope subjected to torsional loading. A geometric model for YS9-8 × 19 braided wire rope was established, and finite element analysis was performed on the model in different twisting directions. The simulation results show that the wires in the strands have the tendency to be screwed tightly and are in a stretched state when the lay direction of the strand coincides with its torsion direction. However, when the lay and torsion directions are opposite, the wires in the strands tend to unwind and are in a compressed state. At the same torsional angle, different torques can be generated at a particular cross-section along different twisting directions. This shows that braided wire rope has better anti-twist characteristics when twisted clockwise compared to when twisted anticlockwise. Finally, a torsion test was conducted on the braided wire rope. The results show that the change in the torque curve with respect to the torsional angle is in good agreement with the simulation results.
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Xu, Dong Qiang, and Mei Mei He. "Seismic Performance Analysis of the Special-Shaped Frame Column Structure on Multi-Dimensional Seismic." Applied Mechanics and Materials 90-93 (September 2011): 1644–48. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1644.
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The article considers the two horizontal components of ground motion and torsional component, to do nonlinear time history analysis both on regular and irregular shaped column frame structure models. The results show that torsional component of ground motion haves some impact on torsion reaction of structures, stiffness of irregular shaped column frame structure is uneven, and angle of columns are greater than that of the regular structure; torsion haves some impact on the torque of structure, the torque increases of corner columns is maximum, so corner columns are weak links in shaped column structure, considered fully during the seismic design.
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Franco, Érika Mendonça Fernandes, Fabrício Pinelli Valarelli, João Batista Fernandes, Rodrigo Hermont Cançado, and Karina Maria Salvatore de Freitas. "Comparative study of torque expression among active and passive self-ligating and conventional brackets." Dental Press Journal of Orthodontics 20, no. 6 (December 2015): 68–74. http://dx.doi.org/10.1590/2177-6709.20.6.068-074.oar.
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Abstract Objective: The aim of this study was to compare torque expression in active and passive self-ligating and conventional brackets. Methods: A total of 300 segments of stainless steel wire 0.019 x 0.025-in and six different brands of brackets (Damon 3MX, Portia, In-Ovation R, Bioquick, Roth SLI and Roth Max) were used. Torque moments were measured at 12°, 24°, 36° and 48°, using a wire torsion device associated with a universal testing machine. The data obtained were compared by analysis of variance followed by Tukey test for multiple comparisons. Regression analysis was performed by the least-squares method to generate the mathematical equation of the optimal curve for each brand of bracket. Results: Statistically significant differences were observed in the expression of torque among all evaluated bracket brands in all evaluated torsions (p < 0.05). It was found that Bioquick presented the lowest torque expression in all tested torsions; in contrast, Damon 3MX bracket presented the highest torque expression up to 36° torsion. Conclusions: The connection system between wire/bracket (active, passive self-ligating or conventional with elastic ligature) seems not to interfere in the final torque expression, the latter being probably dependent on the interaction between the wire and the bracket chosen for orthodontic mechanics.
9
Li, Junqiu, Yihe Wang, and Yizheng Wang. "Optimal control for jitter suppression of clutch engagement in upshift process of electric vehicles." Advances in Mechanical Engineering 8, no. 12 (December 2016): 168781401667484. http://dx.doi.org/10.1177/1687814016674847.
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In the shift process of large-order automatic transmission, jitter phenomenon is common in clutch engagement process, which greatly affects the ride comfort of the vehicle. In this article, the jitter dynamic model of clutch engagement process was established with lumped mass method and virtual displacement principle. Specific to clutch engagement stage, the optimal control of the coordination between driving motor and wet clutch was studied. In accordance with the jitter dynamic model, the state–space equation with controlling variables of motor torque and clutch friction torque was established. In this optimization problem, the torsion angle, torsion angular velocity, and shift jerk are selected as optimization targets. Utilizing the linear quadratic optimal control theory, the optimal trajectory of motor torque and clutch friction torque was obtained. Aiming at the dynamic responses in clutch engagement process, the optimal control in different conditions of weight coefficients, initial torsion angles, and resistance torques was studied. Results showed that the optimal control strategy could obviously reduce the jitter; in addition, the weight coefficient should be determined according to actual situation reasonably.
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Moens, N. M. M., J. Runciman, G. Monteith, and S. Gordon. "The effect of the combination of locking screws and non-locking screws on the torsional properties of a locking-plate construct." Veterinary and Comparative Orthopaedics and Traumatology 23, no. 01 (2010): 7–13. http://dx.doi.org/10.3415/vcot-09-05-0055.
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SummaryLittle is known about the torsional properties of bone-plate constructs when a combination of locking and non-locking screws have been used. Sixty cadaveric canine femurs were divided into three groups. In the first group, the plate was affixed using three non-locking screws. In the second group, only locking screws were used while a combination of one locking and two non-locking screws were used in the third group. All constructs were subjected to torsion until failure. Torque, angle of torsion, and work were all calculated at the maximum failure point, as well as at five degrees of plastic deformation, which was thought to be more representative of clinical failure. At the maximum failure point, the locking group had significantly higher torque, angle, and work values than the non-locking group. The combination group was intermediate to the two other groups, and significantly differed from the non-locking group in torque, and from the locking group in work. At five degrees of plastic deformation, the locking group required significantly higher torque and work than the non-locking group. The combination group required a significantly higher torque than the non-locking group. This study suggests that a construct composed of all locking screws will fail at a greater torque value, and sustain greater work to failure in torsion compared to a construct composed of all non-locking screws. The addition of a single locking screw to an otherwise non-locking construct will increase the torque at the offset failure point and may be of clinical value in constructs subjected to high torsional loads.
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Rostam, Sarkawt, Arazw Hamakarim, Avan Xalid, Pari Said, and Kashab Muhammad. "An Experimental Study of Torsional Properties of Polyvinylchloride." Kurdistan Journal of Applied Research 2, no. 3 (August 27, 2017): 273–78. http://dx.doi.org/10.24017/science.2017.3.24.
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In this research, an experimental study has been performed to investigate the mechanical properties through torsion testing of polyvinylchloride (PVC) polymer specimens. For the purpose of the experimentation, specimens of PVC round bars have been prepared. Torsion testing machine apparatus of 200 Nm motor driven was used to evaluate the torsion properties of the tested bars. The apparatus provides four deformation speeds of 50°/min, 100°/min, 200°/min and 500 °/min. The tests conducted under different conditions in a room temperature and cooling of the samples and tested at different deformation speeds given by the torsion apparatus. Various tests produce the torsional moment- angle of rotation diagrams and thereafter both of torsional fracture resistance and shear modulus have been calculated. The results showed the effect of temperature change on the mechanical properties of PVC by making the material harder and can resist higher value of the applied torque where the range is from 2.9 N.m for the cooled sample to 2 N.m for the received samples tested at room temperature. Moreover the results showed an increase of shear modulus to 282 MPa for the cooled samples in compare to 140 MPa for as received samples. Finally the results provide a guideline for designers on how to use parts made of PVC in different applications where the range of both the maximum torque and failure torque with their mechanical properties of rigidity and torsional resistance were recorded.
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SETKIT, Monthian, Thanongsak IMJAI, Udomvit CHAISAKULKIET, Reyes GARCIA, Komsan DANGYEM, Katipoj SANUPONG, and Weerasit CHAMNANKIT. "Torsional Strengthening of Low-Strength RC Beams with Post-Tensioned Metal Straps: An Experimental Investigation." Walailak Journal of Science and Technology (WJST) 17, no. 12 (December 1, 2020): 1399–411. http://dx.doi.org/10.48048/wjst.2020.11908.
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This article investigates the behaviour of low-strength reinforced concrete beams under pure torsion with and without strengthening. Four beams were cast and tested in torsion: i) a control beam without vertical reinforcement, ii) two beams with internal stirrups designed for shear and torsion demands using different stirrup spacing (50 and 100 mm), and iii) a beam having steel stirrups with a spacing of 100 mm strengthened using high ductile post-tensioned metal straps (PTMS). The main objective of the PTMS strengthening solution was to investigate the enhancement of torsional strength confined along the beam. The failure modes, torsional capacities, rotation, and strengthening performance in torsion are discussed in in this study. The experimental results indicate that the PTMS improved the cracking torque capacity by up to 15 % compared to the control beam. Moreover, the PTMS also increased the ultimate torque by up to 19 % compared to the unstrengthened beam. Current code equations to predict the torsional capacity of RC beams are also compared with the experimental results. It is found that the predictions obtained by current ACI equation gives a good agreement and yield in general conservative values compared to the experimental ones.
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Men, Jin Jie, Qing Xuan Shi, and Qiu Wei Wang. "Unity Equation of Torsional Capacity for RC Members Subjected to Axial Compression, Bend, Shear and Torque." Advanced Materials Research 163-167 (December 2010): 874–79. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.874.
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The mechanics performance of reinforced concrete members subjected to axial compression, bending, shear and torque is very complex. Several calculation models have been established to estimate the torsional capacity of combined torsion members; however, the calculation results of different models have a great variation. In this paper, variable-angle space truss model is adopted to analyze the mechanics performance of reinforced concrete members subjected to combined torsion. With respect to various shapes of specimens, various load modes, and various strength of concrete, a unity equation about torsional capacity of combined torsional member is obtained. Based on the unity equation, the torsional capacity of 59 combined torsional specimens is calculated. In contrast with the equation of ACI and the code of China, the torsional capacity calculated by the unity equation agrees well with the results of experiment and much better than the results of ACI code and China code. It is concluded that the unity equation can provide valuable reference for calculation and design of combined torsion members.
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Ahmed, Mazin Abdul Imam, Jawad Kadhim Mures, and Aqeel Hatem Chkheiwer. "Torsional Behavior of High Strength Concrete Members Strengthened by Mixed Steel Fibers." Journal of Engineering 2021 (July 8, 2021): 1–8. http://dx.doi.org/10.1155/2021/5539623.
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Twelve mixing steel fibers-reinforced high strength concrete beams were experimentally tested under pure torsion to investigating the concrete member torsional behavior. The first cracking torque, ultimate torsional resistance, crack patterns, effect of steel fiber ratio, effects of shape and size of hollow cross-section, and effect of stirrups reinforcement were discussed. The ratio of mixing steel fiber, different shape and size of hollow cross-section, and ratio of stirrups reinforcement were considers as major parameters. The results are shown that the width of cracks decreases and the cracks number increases with mixing steel fibers ratio increased. The first cracking torque and ultimate torsion load increased with decrease in the hollow cross-section area of high strength concrete members strengthened by steel fibers.
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Takahashi, Kosuke, Nyam Jargalsaikhan, Shriram Rangarajan, Ashraf Mohamed Hemeida, Hiroshi Takahashi, and Tomonobu Senjyu. "Output Control of Three-Axis PMSG Wind Turbine Considering Torsional Vibration Using H Infinity Control." Energies 13, no. 13 (July 5, 2020): 3474. http://dx.doi.org/10.3390/en13133474.
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Due to changes in wind, the torque obtained from the wind turbine always fluctuates. Here, the wind turbine and the rotor of the generator are connected by a shaft that is one elastic body, and each rotating body has different inertia. The difference in inertia between the wind turbine and the generator causes a torsion between the wind generator and the generator; metal fatigue and torsion can damage the shaft. Therefore, it is necessary to consider the axial torsional vibration suppression of a geared wind power generator using a permanent magnet synchronous generator (PMSG). In addition, errors in axis system parameters occur due to long-term operation of the generator, and it is important to estimate for accurate control. In this paper, we propose torque estimation using H ∞ observer and axial torsional vibration suppression control in a three inertia system. The H ∞ controller is introduced into the armature current control system (q-axis current control system) of the wind power generator. Even if parameter errors and high-frequency disturbances are included, the shaft torsional torque is estimated by the H ∞ observer that can perform robust estimation. Moreover, by eliminating the resonance point of the shaft system, vibration suppression of the shaft torsional torque is achieved. The results by the proposed method can suppress axial torsional vibration and show the effect better than the results using Proportional-Integral (PI) control.
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Zhao, Y., and S. S. Pang. "Stress-Strain and Failure Analyses of Composite Pipe Under Torsion." Journal of Pressure Vessel Technology 117, no. 3 (August 1, 1995): 273–78. http://dx.doi.org/10.1115/1.2842123.
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An analytical and experimental study was conducted to investigate the elastic and failure behavior of composite laminated pipe under torsion. The analytical model was developed based on the mechanics of composite materials and the maximum strain failure criterion. Five composite pipe samples were tested on a specially designed pipe torsional tester. A finite element analysis was also performed to be compared with the analytical and experimental results. The relationship between applied torque and shear strain and between torque and torsional angles was obtained by all three methods. The effects of fiber angle and its deviation were also studied.
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Garinei, Alberto, and Roberto Marsili. "Development of a non-contact torque transducer based on the laser speckle contrast method." Journal of Sensors and Sensor Systems 6, no. 2 (July 14, 2017): 253–58. http://dx.doi.org/10.5194/jsss-6-253-2017.
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Abstract. When a torque measurement is required, torque transducers show many drawbacks during their use: the usual limits are the need for contact and the effects on shaft line parameters. A new approach is proposed in this work: a non-contact torque meter for a machine shaft has been developed. It carries out torque measurements evaluating the torsional displacement between two distinct sections of the shaft, through the monitoring of their roughness. The sensing principle employed is the classical laser speckle contrast method. The outcoming intensity scattered by the rough surface is processed by a cross-correlation function. In this way, the angular torsion of two distinct sections is obtained. It is therefore possible to point out the applied torque knowing the shaft torsional stiffness.
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Rossel, C., M. Willemin, A. Gasser, H. Bothuizen, G. I. Meijer, and H. Keller. "Torsion cantilever as magnetic torque sensor." Review of Scientific Instruments 69, no. 9 (September 1998): 3199–203. http://dx.doi.org/10.1063/1.1149084.
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Chen, Zong Ping, Ming Zhong, Yu Liang Chen, and Xiang Gang Zhang. "Experimental Study on Torsion Behaviors of Angle Steel Reinforced Concrete Beams." Advanced Materials Research 368-373 (October 2011): 81–84. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.81.
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In order to research the mechanical property of angle steel reinforced concrete beams, 7 specimens were designed for pure torsion experiment. And three running parameters which are sectional steel disposition, thickness of concrete cover and concrete strength are taken into consideration. Base on the test, the torque-torsion angle curve, torque-strain curve, cracking torque, ultimate torque and other important data are obtain. The influences of those parameters are analyzed.
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Martins, Renata de Castro, Maria Guiomar de Azevedo Bahia, and Vicente Tadeu Lopes Buono. "The Influence of Cyclic Straining in Torsion on Fatigue Resistance and Torsional Properties of ProTaper NiTi Endodontic Instruments." Materials Science Forum 643 (March 2010): 79–90. http://dx.doi.org/10.4028/www.scientific.net/msf.643.79.
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This study evaluated the influence of cyclic straining in torsion on fatigue resistance and torsional properties of ProTaper (S1, S2, F1, F2, F3) NiTi instruments. The mechanical behavior was evaluated by means of torsion and bending tests, performed according to ISO 3630-1 specification, while the fatigue resistance was evaluated using a bench test device employing an artificial canal with 5mm curvature radius and angle of curvature of 45º. The dimensional aspects, diameter (D3) and cross-sectional area (A3) at 3mm from the tip of the instruments were determined by means of image analysis of optical and scanning electron microscopy (SEM). The surface characteristics of instruments before and after they were submitted to cyclic straining in torsion and the morphological aspects of the fractured surfaces were analyzed by SEM. The maximum torque and the bending moment at 45º were higher for instruments with larger D3 and A3. The F1 and F2 instruments followed the Coffin-Manson’s relation, i.e., their number of cycles to failure (NCF) varied inversely with the strain amplitude. With the exception of S1 and S2 instruments, there was a tendency of decreasing the maximum torque after the instruments have been submitted to cyclic straining in torsion. With the exception of S1 instruments, there was a tendency of decreasing the NCF after torsional cycling. The analyses by SEM showed the presence of longitudinal cracks on the instruments previously cycled in torsion. The morphological aspects of the fractured surfaces of instruments tested in torsion or flexural fatigue did not changed by the cyclic straining in torsion. These changes in mechanical properties with torsional cycling can be related to the generation of imperfections such as longitudinal cracks on the instruments.
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Sung, Po-Hsien, Tei-Chen Chen, and Cheng-Da Wu. "Atomistic Simulation of ZrNi Metallic Glasses Under Torsion Test." Nano 12, no. 08 (August 2017): 1750094. http://dx.doi.org/10.1142/s1793292017500941.
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ZrNi metallic glass alloy nanowires (NWs) under torsion are studied using molecular dynamics simulations based on the many-body embedded-atom potential. The effect of cooling rate on the deformation mechanism and mechanical properties of ZrNi NWs is evaluated in terms of shear strain, torque, potential energy and radial distribution function. Simulation results show that for slower cooling rates, the NWs have larger packing density, whereas for faster cooling rates, the packing density of atoms decreases. The amount of deformation increases with increasing torsional angle before it reaches a critical torsional angle ([Formula: see text]. The torque required for deformation and the [Formula: see text] value increase with decreasing cooling rate, indicating a larger mechanical strength. Localized shear bands concentrate at regions with high shear strains, leading to the formation of torsional buckling.
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Askandar, Nasih, and Abdulkareem Mahmood. "Comparative Investigation on Torsional Behaviour of RC Beam Strengthened with CFRP Fabric Wrapping and Near-Surface Mounted (NSM) Steel Bar." Advances in Civil Engineering 2019 (September 23, 2019): 1–15. http://dx.doi.org/10.1155/2019/9061703.
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Many researchers worldwide have extensively used fibre-reinforced polymer (FRP) strengthening materials and near-surface mounted (NSM) to enhance the shear and flexural strengths of reinforced concrete (RC) beams. However, studies on torsional strengthening are limited. Although a few studies have focused on torsional strengthening, none of them simultaneously investigated torsion with shear and/or bending moment. This study aims at demonstrating the behaviour of RC beams strengthened with FRP sheets (strips) with different configurations and NSM steel bars with different spacing that was subjected to combined actions of torsion and bending moment and making a comparison between them. Seven beams with a dimension of 15 × 25 × 200 cm were casted. One of the beams was not strengthened; three of them were strengthened with carbon FRP, and the others were strengthened with NSM steel bar. The angle of twist at torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional and strengthened beams during the testing process are compared. Results show a significant improvement in the torsional performance of RC beams using carbon FRP and NSM steel bar. The test beams that were strengthened with CFRP wrapping showed better enhancement in the ultimate torsional moment as opposed to the beams that were strengthened with NSM steel bar.
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Li, Yuan, Yanling Tian, Chengjuan Yang, Kunhai Cai, and Dawei Zhang. "Torsional Properties of Boron Nitride Nanocones with Different Cone Heights, Disclination Angles and Simulation Temperatures." Nano 10, no. 07 (October 2015): 1550097. http://dx.doi.org/10.1142/s1793292015500976.
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The torsional properties of single-walled boron nitride (BN) nanocones at different cone heights, disclination angles and simulation temperatures have been investigated using molecular dynamics (MD) simulation. The simulation results indicate that the torque and average potential energy decrease with the increasing cone height and disclination angle, and the failure torsion angle increases with the increasing cone height and disclination angle. For different simulation temperatures, the torsional behavior of BN nanocones at higher simulation temperature is more serious and earlier to reach a failure point, the maximum torque and average potential energy of the system decrease with the increasing simulation temperature. For different loading rates, the failure torsion angle decreases with the increasing loading rate, so the fracture of BN nanocone occurred earlier with higher loading rate. Therefore, the cone height, disclination angle, simulation temperature and loading rate are considered to be four main influencing factors for the torsional properties of the BN nanocones.
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Ge, Shan, Yu Cheng Yin, and Zhi Qiang Liu. "Development and Application of Test Equipment for Torsion Strength of Non-Metal Materials." Key Engineering Materials 492 (September 2011): 1–4. http://dx.doi.org/10.4028/www.scientific.net/kem.492.1.
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In order to determine the torsion strength of non-metal materials at ambient and high temperature, a kind of equipment with inductive heating, infrared thermometer and torque loading by mechanical electrical rider was development. This equipment has advantages such as quick heating, accurate temperature test and controlling, easy controlling and continues of torque loading and test atmosphere can be controlled. The torsion strength of fireclay bricks with sample size of 40 mm × 40 mm × 230 mm, were tested separately at room temperature, 800°C, 1000°C, 1100°C and 1200°C, using this equipment. Results indicated that for the same batch of samples, the torsion strength determined by this equipment has good consistency, and mean while, it was found that the torsion strength decreased with the increase of test temperature obviously. In additional, developed equipment could be used for the determination of torsion creep at high temperature, the highest temperature of fracture under certain torque during the heating process, torque cycle fatigue failure of materials and so on.
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Alrejaye, Najla, Richard Pober, and Russell Giordano II. "Torsional strength of computer-aided design/computer-aided manufacturing–fabricated esthetic orthodontic brackets." Angle Orthodontist 87, no. 1 (July 12, 2016): 125–30. http://dx.doi.org/10.2319/040416-267.1.
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ABSTRACTObjective: To fabricate orthodontic brackets from esthetic materials and determine their fracture resistance during archwire torsion.Materials and Methods: Computer-aided design/computer-aided manufacturing technology (Cerec inLab, Sirona) was used to mill brackets with a 0.018 × 0.025-inch slot. Materials used were Paradigm MZ100 and Lava Ultimate resin composite (3M ESPE), Mark II feldspathic porcelain (Vita Zahnfabrik), and In-Ceram YZ zirconia (Vita Zahnfabrik). Ten brackets of each material were subjected to torque by a 0.018 × 0.025-inch stainless steel archwire (G&H) using a specially designed apparatus. The average moments and degrees of torsion necessary to fracture the brackets were determined and compared with those of commercially available alumina brackets, Mystique MB (Dentsply GAC).Results: The YZ brackets were statistically significantly stronger than any other tested material in their resistance to torsion (P < .05). The mean torques at failure ranged from 3467 g.mm for Mark II to 11,902 g.mm for YZ. The mean torsion angles at failure ranged from 15.3° to 40.9°.Conclusion: Zirconia had the highest torsional strength among the tested esthetic brackets. Resistance of MZ100 and Lava Ultimate composite resin brackets to archwire torsion was comparable to commercially available alumina ceramic brackets.
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Driver, Robert G., and D. J. Laurie Kennedy. "Combined flexure and torsion of I-shaped steel beams." Canadian Journal of Civil Engineering 16, no. 2 (April 1, 1989): 124–39. http://dx.doi.org/10.1139/l89-028.
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Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.
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Massie, Anna, Tanya Garcia, David Guzman, Po-Yen Chou, Susan Stover, and Amy Kapatkin. "Effects of Hole Diameter on Torsional Mechanical Properties of the Rabbit Femur." Veterinary and Comparative Orthopaedics and Traumatology 32, no. 01 (January 2019): 051–58. http://dx.doi.org/10.1055/s-0038-1676331.
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Objective The aim of this study was to evaluate and compare the effect of three clinically applicable screw hole diameters on rabbit femoral torsional structural properties. Sample Eighteen pairs of skeletally mature New Zealand White rabbit femora (36 bones). Materials and Methods Femora with a bicortical hole at mid-diaphysis from one of the 3-drill bit sizes, 1.1 mm, 1.5 mm, 2.0 mm, and intact bones were studied. Each bone was bi-axially loaded in a servo-hydraulic load frame with the bone positioned so the neutral axis of torsion was aligned with the centre of the bone diaphysis. Axial compression to 35% body weight was applied to represent compression at stance, and rapid external torsion was applied to failure. Torque and angular deformation data were plotted for each test, with pre-yield and post-yield stiffnesses derived. Yield and failure torques and angles were determined, along with calculated yield, failure and post-yield energies. Results Failure torque was reduced compared with that of intact bone; weakened by 37% in 1.1-mm hole models, 53% in 1.5-mm hole models and 65% in 2.0-mm hole models. The torque angular deformation curves lacked plastic deformation. Conclusions and Clinical Relevance This study demonstrates the unique, brittle biomechanics of rabbit bone. Based on data from other species that strength loss of no more than 50% is acceptable when placing orthopaedic implants, no defect greater than 1.1 mm (15% bone diameter) is recommended in rabbit femora.
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MOEENFARD, HAMID. "ANALYTICAL MODELING OF SQUEEZE FILM DAMPING IN DUAL AXIS TORSION MICROACTUATORS." Surface Review and Letters 22, no. 01 (February 2015): 1550006. http://dx.doi.org/10.1142/s0218625x15500067.
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In this paper, problem of squeeze film damping in dual axis torsion microactuators is modeled and closed form expressions are provided for damping torques around tilting axes of the actuator. The Reynolds equation which governs the pressure distribution underneath the actuator is linearized. The resulting equation is then solved analytically. The obtained pressure distribution is used to calculate the normalized damping torques around tilting axes of the actuator. Dependence of the damping torques on the design parameters of the dual axis torsion actuator is studied. It is observed that with proper selection of the actuator's aspect ratio, damping torque along one of the tilting directions can be eliminated. It is shown that when the tilting angles of the actuator are small, squeeze film damping would act like a linear viscous damping. The results of this paper can be used for accurate dynamical modeling and control of torsion dual axis microactuators.
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Dauer, M., A. Wolfbauer, T. Seidlhofer, and U. Hirn. "Shear modulus of single wood pulp fibers from torsion tests." Cellulose 28, no. 12 (July 3, 2021): 8043–54. http://dx.doi.org/10.1007/s10570-021-04027-x.
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AbstractThe shear modulus of pulp fibers is difficult to measure and only very little literature is available on this topic. In this work we are introducing a method to measure this fiber property utilizing a custom built instrument. From the geometry of the fiber cross section, the fiber twisting angle and the applied torque, the shear modulus is derived by de Saint Venant’s theory of torsion. The deformation of the fiber is applied by a moving coil mechanism. The support of the rotating part consists of taut bands, making it nearly frictionless, which allows easy control of the torque to twist the fiber. A permanent magnet moving coil meter was fitted with a sample holder for fibers and torque references. Measurements on fine metal bands were performed to validate the instrument. The irregular shape of the fibers was reconstructed from several microtome cuts and an apparent torsion constant was computed by applying de Saint Venant’s torsion theory. Fibers from two types of industrial pulp were measured: thermomechanical pulp (TMP) and Kraft pulp. The average shear modulus was determined as (2.13 $${\pm }$$ ± 0.36) GPa for TMP and (2.51 $${\pm }$$ ± 0.50) GPa for Kraft fibers, respectively. The TMP fibers showed a smaller shear modulus but, due to their less collapsed state, a higher torsional rigidity than the kraft fibers.
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Ma, Sheng Qiang, Norazura Muhamad Bunnori, and Kok Keong Choong. "Experimental Study on Reinforced Concrete Box Beam Strengthened by CFRP under Combined Action." Applied Mechanics and Materials 802 (October 2015): 184–89. http://dx.doi.org/10.4028/www.scientific.net/amm.802.184.
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An experimental investigation was presented in this paper on reinforced concrete box beams subjected to shear, torsion, and bending moment strengthened by carbon fiber reinforced polymer (CFRP). Eight box beams were cast and separated into two groups according to two different torque-to-shear and torque-to-bending moment ratios. Three box beams from each group strengthened by CFRP in different configurations and one control box beam were tested. The main parameters of this experiment were the different ratios and configurations, including U-jacket layers and U-jacket strips with or without longitudinal strips. The cracking and failure mode, effect of wrapping configuration, torsional capacity, and behavior of the different torque-to-shear and torque-to-bending moment ratios were studied in the paper.
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Li, Dan, Yu Ye Xu, Zheng He Qiu, and Yong Lin Zheng. "Numerical Simulation on the Torsion Behavior of '+'-Shaped Columns under the Actions of Pressure and Torque." Applied Mechanics and Materials 105-107 (September 2011): 796–99. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.796.
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Nonlinear finite element analysis (FEA) for the torsion behavior of reinforced concrete '+'-shaped columns with various axial load ratios was carried out by the general software ANSYS. Then a comparison between the FEA calculations and the test results is made. The numerical examples show that: (1) the cracking torque and ultimate torque of reinforced concrete '+'-shaped columns under the combined actions of axial force and torque can be predicted with a reasonable accuracy. (2) the axial ratio has significant effects on the torsion behavior '+'-shaped columns. The cracking torque and ultimate torque of '+'-shaped columns increase with an increase of axial load ratio. Comparing with reinforced concrete '+'-shaped column with an axial load ratio of 0.063, the cracking torque and ultimate torque of reinforced concrete '+'-shaped columns with axial load ratios of 0.189 and 0.314 were increased by 28.3% and 71.9%, 79.4% and 96.0%, respectively.
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Zhu, Yingbo, Shui Wan, Kongjian Shen, Qiang Su, and Xiayuan Li. "Modified rotating-angle softened truss model for composite box-girder with corrugated steel webs under pure torsion." Advances in Structural Engineering 23, no. 9 (February 6, 2020): 1902–21. http://dx.doi.org/10.1177/1369433219898063.
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Replacement of traditional concrete webs with corrugated steel webs will lead to a significant decrease in torsional stiffness of composite box-girder with corrugated steel webs, which needs special attention in the design of wide and curved composite box-girder with corrugated steel webs. To improve the accuracy of prediction on the entire torsional performance of composite box-girder with corrugated steel webs, a modified rotating-angle softened truss model for torsion is developed in this study. Modified rotating-angle softened truss model for torsion mainly takes into account the new three-stage average stress coefficients, the new two-stage shear strain relationship between corrugated steel web and slabs, and the torsional deformation coordination of whole cross section. To testify the accuracy of modified rotating-angle softened truss model for torsion and to better understand the performance of composite box-girder with corrugated steel webs under pure torsion, two scaled specimens are tested in this article. The torque–twist curves and shear strains calculated by modified rotating-angle softened truss model for torsion reach a good agreement with experimental results, which indicates that modified rotating-angle softened truss model for torsion can successfully predict the entire torsional performance of composite box-girder with corrugated steel webs. In addition, compared with test data obtained from previous literature, the proposed modified rotating-angle softened truss model for torsion is more capable of predicting full torsional response of composite box-girder with corrugated steel webs than other rotating-angle models, especially at cracking stage and ultimate stage.
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Ashour, Samir A., Sabry A. Shihata, Ali A. Akhtaruzaman, and Faisal F. Wafa. "Prestressed high-strength concrete beams under torsion and bending." Canadian Journal of Civil Engineering 26, no. 2 (April 1, 1999): 197–207. http://dx.doi.org/10.1139/l98-054.
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Test results of 16 rectangular prestressed high-strength concrete beams subjected to the combined action of torsion and bending are presented. The major variables were the ratio of torsion to the bending moment (T/M) and the prestressing level. The beams were subjected to two levels of prestressing, corresponding to 0.05fc' and 0.10fc', where fc' is the compressive strength of concrete (about 90 MPa). Test results showed that the torque-twist relations for the test beams were approximately linear up to cracking and thereafter became nonlinear. Increasing the T/M ratio and the prestressing level increases both torsional stiffness and strength. Several theoretical methods available in the literature developed for normal-strength concrete were used to predict the torsional strength of the tested high-strength concrete beams. Interaction equations were used along with some other methods to predict the torsional capacity in the presence of a bending moment. Good agreement was observed between the experimental and theoretical results.Key words: beams (supports), bending, cracking, failure, high-strength concrete, interaction diagram, prestressed concrete, stiffness, torsion, torsional strength.
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Sun, Heng Hui, Ai Wu Zhao, Mao Feng Zhang, Da Li, Da Peng Wang, Li Kai Zhu, and Mei Tao. "The Analysis Model of Torsion Behavior for Octopus-Inspired Robotic Arm." Applied Mechanics and Materials 461 (November 2013): 917–23. http://dx.doi.org/10.4028/www.scientific.net/amm.461.917.
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Abstract. Octopus can achieve a variety of dexterous movements at any point along its arm, such as elongating, shorting, bending, twisting, or changing the stiffness, which have been considered as an interesting model of inspiration in robotics. Among the complex behaviors, the torsion behavior is important because it provide extra degree of freedom of movement, like twisting. This paper proposed a detailed dynamic model that describes the torsion behavior of octopus arm, based on torsional vibration theory. The initial conditions and boundary conditions that explained the main features of the torsion behaviors of octopus arm are acknowledged. The mode shapes, which describe the torsional vibration frequency and type, were solved as the sum of the time and the distance from the fixed end to where the deformation happened. By comparing the mode shapes results solved by the method proposed in this paper and by FEA Soft ANSYS, the effectiveness of this method has been verified. Further torsional stresses and torsion angles of deformation and vibrations on rod can be expressed as the functions of the mode shapes and the external torque exerted on one end of the rod. This method can be applied to calculate the kinematics results of the torsion behaviors and the appropriate activations related for continuum robotic manipulators inspired by octopus arm.
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Ali, A. R. M., and M. S. J. Hashmi. "Theoretical and experimental results of the elastic—plastic response of a circular rod subjected to non-proportional combined torque and tension loadings." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 3 (March 1, 1999): 251–61. http://dx.doi.org/10.1243/0954406991522626.
Full textAbstract:
Experimental and theoretical results concerning the elastoplastic response of a circular steel rod subjected to non-proportional biaxial loadings are reported. The following loading paths were studied: elastoplastic torsion followed by tension, keeping the initial angle of twist constant, and elastoplastic tension followed by torsion, holding the initial axial displacement constant. Experimental results show that when the rod is initially subjected to a torque and then, keeping the corresponding angle of twist constant, to a gradually increasing axial load, the rod behaves as if its torque-carrying ability has been drastically reduced without in any way affecting its axial load-carrying ability. Similarly, when the rod is initially subjected to an axial load and then, keeping the corresponding axial displacement constant, to a gradually increasing torque, the rod behaves as if its load-carrying ability has been considerably reduced without in any way affecting its torque-carrying ability. The mechanisms of such reduction are discussed in relation to the theoretical predictions based on Gaydon's [1] analytical model. Numerical solution has also been obtained along the lines of the above-mentioned model. The findings of this work have a direct bearing on the relaxation of tightening torques or axial loads as experienced by critical engineering components, such as couplings, bolted joints and rotating shafts, that are subjected to similar types of biaxial loading.
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Křístek, Vladimír, Jaroslav Průša, and Jan L. Vítek. "Torsion of Reinforced Concrete Structural Members." Solid State Phenomena 272 (February 2018): 178–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.178.
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According to the common design methods of calculation of the stress state induced by torsion of massive prismatic concrete structural elements, the structural system is reduced to a simple cage consisting of ties and struts. This model has, however, a number of principal shortcomings, the major of them is the fact that all of simultaneously acting effects like axial forces, bending moments and shear forces are not taken into account – the compressive axial forces increase very significantly the torque capacity of structural members, while due to action of tensile forces, bending moments and shear forces the torque capacity is reduced. These phenomena, applying non-linear approaches, are analysed and assessed.
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Assad-Loss, Tatiana Feres, Flávia Mitiko Fernandes Kitahara-Céia, Giordani Santos Silveira, Carlos Nelson Elias, and José Nelson Mucha. "Fracture strength of orthodontic mini-implants." Dental Press Journal of Orthodontics 22, no. 3 (June 2017): 47–54. http://dx.doi.org/10.1590/2177-6709.22.3.047-054.oar.
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ABSTRACT Objective: This study aimed at evaluating the design and dimensions of five different brands of orthodontic mini-implants, as well as their influence on torsional fracture strength. Methods: Fifty mini-implants were divided into five groups corresponding to different manufactures (DEN, RMO, CON, NEO, SIN). Twenty-five mini-implants were subjected to fracture test by torsion in the neck and the tip, through arbors attached to a Universal Mechanical Testing Machine. The other 25 mini-implants were subjected to insertion torque test into blocks of pork ribs using a torquimeter and contra-angle handpiece mounted in a surgical motor. The shape of the active tip of the mini-implants was evaluated under microscopy. The non-parametric Friedman test and Snedecor’s F in analysis of variance (ANOVA) were used to evaluate the differences between groups. Results: The fracture torque of the neck ranged from 23.45 N.cm (DEN) to 34.82 N.cm (SIN), and of the tip ranged from 9.35 N.cm (CON) to 24.36 N.cm (NEO). Insertion torque values ranged from 6.6 N.cm (RMO) to 10.2 N.cm (NEO). The characteristics that most influenced the results were outer diameter, inner diameter, the ratio between internal and external diameters, and the existence of milling in the apical region of the mini-implant. Conclusions: The fracture torques were different for both the neck and the tip of the five types evaluated. NEO and SIN mini-implants showed the highest resistance to fracture of the neck and tip. The fracture torques of both tip and neck were higher than the torque required to insert mini-implants.
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Liu, Yuwang, Tian Tian, Jibiao Chen, Fuhua Wang, and Defu Zhang. "A Highly Reliable Embedded Optical Torque Sensor Based on Flexure Spring." Applied Bionics and Biomechanics 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/4362749.
Full textAbstract:
We propose a new highly reliable and lightweight embedded optical torque sensor for biomimetic robot arm enabling the torque measurement in joints, which can measure torque of the joint by detecting torsion of its elastic element (mechanical structure or flexure element). Flexure spring is introduced as the elastic element of the torque sensor in this paper. Because of its curve modeling, flexure spring is not inclined to be broken contrast to crossbeam structure, which is commonly used in torque sensor. Thanks to this structure, we can build a torque sensor as an extremely compact and highly reliable size. Six types of flexure spring are proposed to be used as the elastic element of the torque sensor in this paper, which have the potential for the requirements of measurement range and multidimensional detection. The optical electronic, less influenced by electromagnetic interferences, is selected to measure the torsion displacement of the flexure spring. The proposed design is analyzed, which can obtain the successful measurement of the torque with a load capacity of 1 Nm. One of the designed optical torque sensors is optimized by FEM. The calibration and experiment are conducted to ensure its feasibility and performance.
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Xu, Jianchao, Bo Diao, Quanquan Guo, Yinghua Ye, Y. L. Mo, and Tianmin Zhou. "Parametric Study on Mixed Torsional Behavior of U-Shaped Thin-Walled RC Girders." Advances in Civil Engineering 2018 (November 15, 2018): 1–18. http://dx.doi.org/10.1155/2018/3497390.
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Nowadays, U-shaped thin-walled concrete girders have been widely applied in the urban construction of rail viaducts in China as well as worldwide. However, the mixed torsional behaviors of these structures are not well understood. In this paper, the mixed torsional behaviors of the U-shaped thin-walled RC girders are theoretically analyzed, and a method predicting failure modes and ultimate torques is proposed. Nonlinear FE models based on ABAQUS to simulate the mixed torsional behaviors are built and calibrated with the test results. Parametric studies considering three crucial parameters (boundary condition, span length-section height ratio, and ratio of longitudinal bars to stirrups) are conducted based on both the above suggested calculating method and the FE modeling. The calculated and the simulated results agree well with each other and with the test results. It is found that the failure modes of the U-shaped thin-walled RC girders under torsion are influenced by all the three parameters. Three kinds of failure modes are observed: flexural failures dominated by warping moment, shear failures caused by warping torque and circulatory torque, and flexural-shear failures in the cases where flexural failure and shear failure appear almost at the same time.
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Jiang, Chenchen, Haojian Lu, Ke Cao, Wenfeng Wan, Yajing Shen, and Yang Lu. "In Situ SEM Torsion Test of Metallic Glass Microwires Based on Micro Robotic Manipulation." Scanning 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/6215691.
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Microwires, such as metallic, semiconductor, and polymer microwires and carbon fibers, have stimulated great interest due to their importance in various structural and functional applications. Particularly, metallic glass (MG) microwires, because of their amorphous atoms arrangement, have some unique mechanical properties compared with traditional metals. Despite the fact that substantial research efforts have been made on the mechanical characterizations of metallic glass microwires under tension or flexural bending, the mechanical properties of microwires under torsional loading have not been well studied, mainly due to the experimental difficulties, such as the detection of torsion angle, quantitative measurement of the torsional load, and the alignment between the specimen and torque meter. In this work, we implemented the in situ SEM torsion tests of individual La50Al30Ni20 metallic glass (MG) microwires successfully based on a self-developed micro robotic mechanical testing system. Unprecedented details, such as the revolving vein-pattern along the torsion direction on MG microwires fracture surface, were revealed. Our platform could provide critical insights into understanding the deformation mechanisms of other microwires under torsional loading and can even be further used for robotic micromanufacturing.
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Orie, O. U. "An Assessment of Torsional Parameters of Steel Reinforcement Used in the Nigerian Construction Industry." Advanced Materials Research 62-64 (February 2009): 44–50. http://dx.doi.org/10.4028/www.scientific.net/amr.62-64.44.
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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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Zhou, Bo, Zhen Qing Wang, Yan Ju Liu, and Jin Song Leng. "Investigation on Mechanical Behaviors of Shape Memory Alloy Torsion Rod." Advanced Materials Research 179-180 (January 2011): 455–58. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.455.
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DSC test is carried out to determine the phase transformation temperatures of a NiTi SMA, which include martensitic starting temperature, martensitic finishing temperature, austenitic starting temperature and austenitic finishing temperature. The mechanical behaviors of shape memory alloy (SMA) torsion rod are investigated by using Zhou’s shear constitutive equation of SMA and the theorem of circular shaft in mechanics of materials. A critical torque equation is developed to describe the relationship between the martensitic phase transformation critical torque of SMA torsion rod and temperature.
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Yan, Ming, Peng Zheng, Yan Li, and Xiu Feng Gao. "Finite Element Analysis of C Axis of High-Power Direct-Drive Bi-Rotary Milling Head." Applied Mechanics and Materials 34-35 (October 2010): 202–6. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.202.
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In a direct-drive high-power A / C-axis bi-rotary milling head, torque is transferred by two parallel connected rotary direct drive motors in C-axis, therefore, the length of C axis is inevitable large, moreover, the transmission components of it are bearing high torque. The torsion deformation of C axis must compute accurately during the design process. The torsion deformation of the transmission components of C parts when C-axis is rotating is analyzed by finite element method, the racial deformation and the torsion deformation of the case when C-axis is locking are analyzed either, this computing can provide support for the design and improvement of this type of milling head.
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Li, Tan, and Guo Biao Shi. "Study of EPS Hall-Effect Torque Sensor Technology." Advanced Materials Research 422 (December 2011): 107–12. http://dx.doi.org/10.4028/www.scientific.net/amr.422.107.
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In an electric power steering (EPS) system, it is important to make a precise and reliable measurement of the torque on the steering wheel. A non-contact torque sensor has been developed for EPS system. The sensor is based on a magnetic principle that the magnetic flux path is changed with the torsion of a torsion bar which is placed in the steering shaft. The change of magnetic flux density in the working airgap is detected by a standard Hall-effect IC. The sensor has broad prospects for its good performance, simple structure and low cost. This paper introduces the torque sensor’s working principle, analyzes the magnetic circuit by 3D simulation, and concludes its key technologies and development trends.
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Diken, H., and I. G. Tadjbakhsh. "Unbalance Response of Flexible Rotors Coupled With Torsion." Journal of Vibration and Acoustics 111, no. 2 (April 1, 1989): 179–86. http://dx.doi.org/10.1115/1.3269839.
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The effect of coupling with torsion on the unbalance response of flexible rotors, supported by isotropic flexible and damped bearings is investigated. Flexural vibrations of the shaft-disk system are coupled with torsional oscillations through mass eccentricity. The governing equations of motion of the continuous system are solved numerically with a modified Myklestad-Prohl method without the necessity of considering an equivalent lumped system. The cases of constant or harmonic torque applied to the disk are considered. Gyroscopic, rotary inertia, shear deformation, external and internal damping effects are taken into account.
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Ha, Kwangtae. "Innovative Blade Trailing Edge Flap Design Concept using Flexible Torsion Bar and Worm Drive." HighTech and Innovation Journal 1, no. 3 (September 1, 2020): 101–6. http://dx.doi.org/10.28991/hij-2020-01-03-01.
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In this paper, a simple but effective trailing edge flap system was proposed. This preliminary concept uses a more practical and stable actuation system which consists of a motor-driven worm gear drive and flexible torsion bar. The flexible torsion bar is designed to be easily twisted while keeping bending rigidity as a sup-port and the worm gear drive not only provides a high torque to overcome aero-dynamic forces on the flap area and the torsional rigidity of the support bar, but also acts as a brake to avoid instability due to the high torsional flexibility of sup-port bar. A preliminary level design study was performed to show the applicability of the new trailing edge flap system for wind turbine rotor blade or helicopter blade.
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Mansour, Gabriel, Kostas Tzikas, Dimitrios Tzetzis, Apostolos Korlos, Dimitrios Sagris, and Kostas David. "Experimental and Numerical Investigation on the Torsional Behaviour of Filament Winding-Manufactured Composite Tubes." Applied Mechanics and Materials 834 (April 2016): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amm.834.173.
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The present work is focused in the examination of the torsional behaviour of composite tubes by a combined experimental and numerical approach. Glass and carbon composite tubes were manufactured by the filament winding technique. All the tubes were fabricated with glass and carbon Fiber orientation at ±45°. The effect of the torsional loading on the mechanical strength of the glass and carbon composite tubes was initially studied experimentally. Angular velocity of 5° per min was used as torsion test speed while torque-twisting angle changes were recorded. The torsional behaviour of composite tubes was also simulated using Finite Element Analysis (FEA). An elastic orthotropic composite model was used for the simulations. The normal and shear stress contours were obtained from the FE models, while the theoretical relation of the torque versus the twisting angle was calculated. Comparison of the numerical and experimentally obtained results has shown a relatively similar torsional behaviour.
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Chen, Dongliang, Jindong Zhang, Xutao Weng, Yunjian Zhang, and Zhonghui Shi. "Analysis of Stiffness and Energy Consumption of Nonlinear Elastic Joint Legged Robot." Applied Bionics and Biomechanics 2020 (July 14, 2020): 1–10. http://dx.doi.org/10.1155/2020/8894399.
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In order to reduce the energy consumption of the legged robot in walking, this paper designs a kind of nonlinear elastic joint from the flexible variable-stiffness joint based on the mammal walking on the limb and optimizes the leg structure of the legged robot. The motor is rigidly connected to the articulated lever. When the lever is accelerated or decelerated, the elastic unit is introduced. The system can be considered as a special variable-rate elastic system. This paper will study it from theory and simulation experiments. Based on the dynamic analysis, a functional relationship between the output torque and the torsion spring stiffness and between the energy consumption and the torsion spring stiffness was established. By finding the extremum, the two optimum torsional spring stiffness that can minimize the required output average torque and the energy consumed during one cycle of motion were deduced. The results show that using this design in a reasonable position can effectively reduce the energy consumption of the system and can achieve up to a 50% reduction in energy consumption.
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Tobushi, Hisaaki, Elzbieta Pieczyska, W. K. Nowacki, and Y. Sugimoto. "SMA Thin Strip for Rotary-Driving Element." Solid State Phenomena 154 (April 2009): 47–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.154.47.
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If a shape-memory alloy (SMA) thin strip is applied as an element subjected to torsion, a rotary driving element with a simple mechanism can be developed. The torsion tests were carried out for the SMA thin strip. Torque and recovery torque, both increase in proportion to the angle of twist and temperature. The recoverable strain energy increases in proportion to temperature. The dissipated work decreases slightly with an increase in temperature. A means of opening and closing a door with an element driven by an SMA thin strip is demonstrated.
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Gusel, Leo. "Multi Regression Analysis of Flow Curve Obtained by Torsion Test." Advanced Materials Research 856 (December 2013): 159–63. http://dx.doi.org/10.4028/www.scientific.net/amr.856.159.
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This paper presents determination of flow curve of steel by using multi regression analysis based on only few experimental points of torsion test. It is necessary to know the flow curve of the formed metal and the best way to obtain one are different experiments such as tensile, upsetting or torsion tests. In the paper torsion test was used for obtaining the flow curve. In torsion test a cylindrical specimen is twisted by torque acting around its axis. Experimental data of torsion test were processed by determination of statistical characteristic of experimental results.