Journal articles on the topic 'Deflection'
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1
Umasankar, G., and C. R. Mischke. "A Simple Numerical Method for Determining the Sensitivity of Bending Deflections of Stepped Shafts to Dimensional Changes." Journal of Vibration and Acoustics 107, no. 1 (January 1, 1985): 141–46. http://dx.doi.org/10.1115/1.3274706.
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A simple method of computing the effect of a dimensional change at a particular element of a stepped shaft on two bearings, on bending deflections, and on slopes of the neutral axis at any of the nodes of interest is presented. The changes in deflection and slope of the neutral axis are derived as incremental quantities and as functions of the dimension change and the prior deflections and slopes of the neutral axis of the shaft. For shaft synthesis, the implications are that one can begin with a uniform diameter bar subjected to the loading and make a complete deflection analysis with superposed closed-form relations. Then the geometry can be modified element by element and the deflectional changes easily updated. This is computationally efficient. Further, deflections and deflection changes computed using the proposed method are identical to those obtained using a finite beam element model of the shaft.
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Shi, Shao Yan, Yi Jiang, and Xiao Tong Dong. "Deflecting Features of Gas from Double-Faced Deflector and Structure Optimization of Deflector." Applied Mechanics and Materials 387 (August 2013): 314–18. http://dx.doi.org/10.4028/www.scientific.net/amm.387.314.
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This paper uses three-dimensional dynamical simulation of gas jet to demonstrate basic deflecting features of the double-faced deflector, during the launch process of the land-based missile with the vehicle-mounted vertically thermal launch. The calculation shows that the deflection of the gas flow is good, reducing knock-on effect and ablative effect on launch device. But wheels of the launch vehicle are still under visible influent from the gas flow. The paper optimizes the double-faced deflector and compares different suggestions in order to find a better deflection.
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D. G., Verbylo. "Study the deformation behavior of materials under bending." Uspihi materialoznavstva 2023, no. 6 (June 1, 2023): 75–85. http://dx.doi.org/10.15407/materials2023.06.075.
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The application of bending tests is due to the widespread use of this load scheme in real operating conditions and its greater softness compared to tensile strength. This makes it possible to assess the properties of materials that are brittle when tensile. Bending tests are convenient for estimating the transition temperatures from brittle to plastic (for example, in cold-brittle BCC metals and intermetallics). The issue of determining the elastic characteristics, in particular the measurement of deflections, needs to be clarified. The aim of this work is to improve experimental methods for determining the characteristics of elasticity, in particular to determine the ratio of movement of internal rollers relative to external and deflection between internal rollers, as well as accurate determination of absolute deformation of the test machine depending on load. To obtain the deformation curve of the sample without the deflection meter, a method of subtracting from the total load curve the yield curve of the test machine, which can be obtained after testing the sample with a high axial moment of inertia to minimize its deflection. To test this technique, a ceramic sample based on Al2O3 was tested. After the adjustments, it was found that the modulus of elasticity was 371.3 GPa, which corresponds to the tabular values. The proposed technique allows to accurately measure the modulus of elasticity and obtain curves of microdeformation of low-plastic materials at different test temperatures in the absence of a deflector. The deflection of the central part of the sample relative to the inner rollers by four-point bending is 3/8 of the movement of the inner rollers relative to the outer ones. The improved method of determining the deflections allows to obtain diagrams of deformation of the samples without the deflection meter, as well as to measure the modulus of elasticity and obtain curves of microdeformation of low-plastic materials at different test temperatures. Comparison of the results of determining the modulus of elasticity by methods without a deflector and with it allows you to assess the accuracy of measuring the modulus of elasticity. It is experimentally established that the difference between the values of the Young's modules calculated by the proposed method and the corresponding values calculated taking into account the directly measured deflections does not exceed 1%. Keywords: bending, stress, deformation, deflection, angle of rotation, radius of curvature, axial moment of inertia, deflection meter.
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Žiga, Alma, and Josip Kačmarčik. "Plywood Cantilever Deflection." Drvna industrija 74, no. 1 (March 25, 2023): 81–91. http://dx.doi.org/10.5552/drvind.2023.0053.
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In this paper, the elastic behaviour in bending of three-layer plywood cantilever beams is analysed. Deflections of straight and half-circle cantilevers, loaded with a force at free end is determined experimentally and calculated using analytical and finite element method approach. The analytical calculation of deflection for the strait cantilever is obtained using a transformed cross section. The deflection of half-circle cantilever is determined by the classical laminated plate theory and Castigliano’s theorem. Loads and cantilever dimensions are varied in the study using the design of experiment. The deflection regression models for straight and semicircular plywood cantilevers are obtained from the experimental results. Analytically and numerically determined deflections of strait and half-circle cantilevers show very good agreement. Experimentally recorded deflections are approximately 30 % higher than analytical values. Stiffness properties and deflection values are influenced by direction of fibres in the outer layers of a three-layer plywood beam.
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Kim, Sang-Woo. "Prediction of Deflection of Shear-Critical RC Beams Using Compatibility-Aided Truss Model." Applied Sciences 11, no. 23 (December 3, 2021): 11478. http://dx.doi.org/10.3390/app112311478.
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This study proposes a method for predicting the deflection of shear-critical reinforced concrete (RC) beams. Shear deterioration of shear-critical RC beams occurs before flexural yielding. After shear deterioration occurs in the shear-critical RC beams, the deflection caused by shear is greater than the flexural deflection obtained from the elastic bending theory. To reasonably predict the deflection of shear-critical RC beams, it is necessary to evaluate deflections due to shear as well as flexure. In this study, the deflections produced by flexure and shear were calculated and superposed to evaluate the deflection of shear-critical RC beams. The method recommended by ACI 318-19 was employed to calculate the flexural deflection, and a compatibility-aided truss model able to calculate the shear stress and shear deformation at each load stage was used to consider the shear deflection. A comparison of the experimental and analytical results showed that the proposed analytical method can effectively predict the deflection of shear-critical RC beams.
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Elvin, Niell G., and Alex A. Elvin. "Large deflection effects in flexible energy harvesters." Journal of Intelligent Material Systems and Structures 23, no. 13 (February 20, 2012): 1475–84. http://dx.doi.org/10.1177/1045389x11435434.
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The effect of large deflection on the mechanical and electrical behaviors of flexible piezoelectric energy harvesters has not been well studied. A generalized nonlinear coupled finite element circuit simulation approach is presented in this article to study the performance of energy harvesters subjected to large deflections. The method presented is validated experimentally using three test examples consisting of (a) a static case, (b) a free vibration case, and (c) a forced vibration case. Under static conditions (when the transverse tip deflection exceeds a quarter of the cantilever length), large deflections cause geometric stiffening of the structure that reduces the tip deflection of the generator when compared to linear (i.e. small-deflection) behavior. For a cantilever generator under dynamic conditions, geometric stiffening, inertial softening, and nonlinear damping effects become significant. Large deflections both shift the resonant frequency and increase damping and can thus cause a significant reduction in output voltage when compared with small-deflection linear theory. In the finite element generator model studied in this article, these nonlinear dynamic effects become significant when the transverse tip deflection exceeds 35% of the beam length.
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Turner, Dennis J., Jeffrey L. J. Lee, Kenneth H. Stokoe, Richard L. Boudreau, Quintin B. Watkins, and George K. Chang. "Discrete and Continuous Deflection Testing of Runways at Hartsfield Atlanta International Airport, Georgia." Transportation Research Record: Journal of the Transportation Research Board 1860, no. 1 (January 2003): 76–89. http://dx.doi.org/10.3141/1860-09.
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The measurement of deflection characteristics is a key feature in the evaluation of pavements. Deflections are used to evaluate pavement moduli, relative stiffness, load transfer, and, when used periodically, a rate of deterioration and remaining life. The comprehensive deflection testing program conducted on Runways 9L/27R and 8R/26L, both jointed concrete pavements, at the Hartsfield Atlanta International Airport is described. A heavy-weight deflectometer was used to measure deflections at discrete locations on slab interiors, transverse joints, longitudinal joints, and slab corners. A rolling dynamic deflectometer was used to measure continuous deflection profiles along three longitudinal lines on both runways. Before fall 2001, all pavement deflection testing was performed using a falling-weight deflectometer. Comparisons of the equipment, loading mechanisms, and measured deflections are presented.
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Onsa, Eltayeb Hassan, Elsafi Mohamed Adam, Abdalla Khogali Ahmed, and Mohamed Elmontasir Elbagir. "Long-term Deflections in Balanced Cantilever Prestressed Concrete Bridges." FES Journal of Engineering Sciences 4, no. 1 (December 6, 2009): 22. http://dx.doi.org/10.52981/fjes.v4i1.41.
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Long-term deflections in balanced cantilever prestressed concrete bridges are reviewed. Burri and Shambat Bridges are taken as cases study to calculate long-term deflection. The two bridges were constructed at Khartoum State in the years 1972 and 1962, respectively. Due to the shortage of the basic data regarding the two bridges the AASHTO-LRFD is used to estimate and calculate the missing data in the two bridges. The Moment Area method is used to calculate the long-term deflections due to the dead load, live load and prestressing force. The calculated long-term deflections are compared with measured live load deflections obtained from load tests made by a Chinese contractor requested to evaluate the two bridges. Remarkable differences between theoretical and measured deflection at the end of cantilevers are encountered. The differences are probably due to the basic assumptions made in the formulations of deflection calculations. Some adjustments in the long-term deflection formulae are suggested to bring the calculated deflections in compatibility with measured ones.
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Mahale, Harsh N., Prof Ravindra N. Patil, Vrushali R. Bagul, and Megha L. Badade. "Bridge Load Testing as Per IRC SP 51." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (May 31, 2022): 3759–68. http://dx.doi.org/10.22214/ijraset.2022.43367.
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Abstract: Bridge load testing is popular means of demonstrating bridge’s capability to carry safely design loads. It is commonly used to determine the issues which cannot be resolved by only visual inspection or analysis. This paper deals with the study of load testing of major Bridge on River of 17.20 meter span Between Pier P5 and Pier P6. Under this project bridge was loaded with vehicular loading and tested for design load. Deflection of bridge is measured by dial gauges and recorded for bridge analysis. This study consists preparation of load test on bridge for deflection load as per IRC SP 51(2015) and how load testing is carried out by visual inspection, by applying vehicular loading or dynamic loading , its behaviour under loading and unloading conditons, behavior of bridge under the different temperatures to check how bridge is going to behave under weather conditions , maximum permissible deflection of girders , total deflection of girders, total recovery and percentage recovery of deflections after removal of load and comparison between theoretical deflections and actual deflections to find out testing bridge capability and its structural integrity. Keywords: Bridge Load Test, Dial Gauge, vehicles, Loading, Unloading, Deflection, Design load, Temperature effect, Temperature correction, Total recovery, Total Deflection, Theoretical Deflection, Percentage recovery.
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Tawfiq, Kamal, John Sobanjo, and Jamshid Armaghani. "Curvilinear Behavior of Base Layer Moduli from Deflection and Seismic Methods." Transportation Research Record: Journal of the Transportation Research Board 1716, no. 1 (January 2000): 55–63. http://dx.doi.org/10.3141/1716-07.
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The reality of curvilinear relationships of stiffness versus deformation is usually neglected when moduli values from seismic methods are compared with those of deflection methods. On the basis of extensive field testing, results showed that moduli values for the base layers from deflection methods did not conform to those of seismic methods. Deflection testing techniques were signified by the falling weight deflectometer (FWD) and the Dynaflect methods. Seismic testing was carried out by use of the seismic pavement analyzer (SPA) method. The SPA test results yielded moduli values higher than those obtained from the deflection methods. Utilizing pavement parameters obtained from the SPA data, researchers determined surface deflections by use of frequency response functions of signals from the two groups of sensors used in the testing setup. Because of the types of hammers in the SPA testing, two different deflection basins were obtained at each testing point. Comparison of surface deflections from these methods indicated that deflection amplitudes from the FWD method were about 100 times higher than those obtained from the high-frequency hammer of the SPA. At certain pavement sections, deflections from the Dynaflect method were comparable to those obtained with the SPA low-frequency hammer. Accordingly, curvilinear relationships between surface deformation versus stiffness values were derived. These relationships can be used to determine moduli values at all surface deflections, including those from service loads.
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Zihan, Zia U. A., Mostafa A. Elseifi, Patrick Icenogle, Kevin Gaspard, and Zhongjie Zhang. "Mechanistic-Based Approach to Utilize Traffic Speed Deflectometer Measurements in Backcalculation Analysis." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 5 (April 16, 2020): 208–22. http://dx.doi.org/10.1177/0361198120914296.
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Backcalculation analysis of pavement layer moduli is typically conducted based on falling weight deflectometer (FWD) deflection measurements; however, the stationary nature of the FWD requires lane closure and traffic control. In recent years, traffic speed deflection devices such as the traffic speed deflectometer (TSD), which can continuously measure pavement surface deflections at traffic speed, have been introduced. In this study, a mechanistic-based approach was developed to convert TSD deflection measurements into the equivalent FWD deflections. The proposed approach uses 3D-Move software to calculate the theoretical deflection bowls corresponding to FWD and TSD loading configurations. Since 3D-Move requires the definition of the constitutive behaviors of the pavement layers, cores were extracted from 13 sections in Louisiana and were tested in the laboratory to estimate the dynamic complex modulus of asphalt concrete. The 3D-Move generated deflection bowls were validated with field TSD and FWD data with acceptable accuracy. A parametric study was then conducted using the validated 3D-Move model; the parametric study consisted of simulating pavement designs with varying thicknesses and material properties and their corresponding FWD and TSD surface deflections were calculated. The results obtained from the parametric study were then incorporated into a Windows-based software application, which uses artificial neural network as the regression algorithm to convert TSD deflections to their corresponding FWD deflections. This conversion would allow backcalculation of layer moduli using TSD-measured deflections, as equivalent FWD deflections can be used with readily available tools to backcalculate the layer moduli.
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Lee, Chang-Hwan, Iman Mansouri, Jaehoon Bae, and Jaeho Ryu. "Current and New Approaches to Predict the Deflections of One-Way Flexural Members with a Focus on Composite Steel Deck Slabs Voided by Circular Tubes." Materials 14, no. 2 (January 16, 2021): 421. http://dx.doi.org/10.3390/ma14020421.
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A new type of composite voided slab, the TUBEDECK (TD), which utilizes the structural function of profiled steel decks, has recently been proposed. Previous studies have confirmed that the flexural strength of TD slabs can be calculated based on the full composite contribution of the steel deck, but for long-span flexural members, the deflection serviceability requirement is often dominant. Herein, we derived a novel deflection prediction approach using the results of flexural tests on slab specimens, focusing on TD slabs. First, deflection prediction based on modifications of the current code was proposed. Results revealed that TD slabs exhibited smaller long-term deflections and at least 10% longer maximum span lengths than solid slabs, indicating their greater efficiency. Second, a novel rational method was derived for predicting deflections without computing the effective moment of inertia. The ultimate deflections predicted by the proposed method correlated closely with the deflection under maximum bending moments. To calculate immediate deflections, variation functions for the concrete strain at the extreme compression fiber and neutral axis depth were assumed with predictions in good agreement with experiments. The proposed procedure has important implications in highlighting a new perspective on the deflection prediction of reinforced concrete and composite flexural members.
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Du, Jin Sheng, and Hai Bin Liu. "Effect of Pier Vertical Deformations on Deflections of Main Girders for High Pier and Long-Span Continuous Rigid-Frame Bridges." Advanced Materials Research 163-167 (December 2010): 1436–39. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1436.
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In some long-span prestressed concrete box girder bridges, excessive deflections of main girders are often observed. These unacceptable deflections have detrimental influence on the serviceability and safety of the structures. To better understand and estimate short term and long term deflections for prestressed concrete box girder bridges, pier vertical deformation and its effect on deflections of main girders of Jinghe Bridg is investigated in this paper. Piers in Jinghe Bridge are tall and the difference in height between piers up to 22 m. Analysis indicates that although the short term deformations of piers are small, the long term deformations of piers can be 3 times as large as that of short-term ones. The maximum short-term downward deflection of Jinghe Bridge caused by pier deformation for main girders is 7.7 mm and the maximum long-term downward deflection is 33.3 mm. These values are relatively small compared with the span length of the bridge. But when the deflection of the main girder itself is also included, the final total deflection of the main girder may exceed the design code limit.
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Vyazankin, Vitaliy Valer'evich, and Victor Andreevich Mamontov. "Statistical data on crankshaft deflections of marine diesel engine." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2023, no. 3 (August 31, 2023): 27–32. http://dx.doi.org/10.24143/2073-1574-2023-3-27-32.
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The results of the study of crankshafts that have received a deflection during operation are presented. The reasons for the appearance of the curvature of the longitudinal axis and the consequences to which this defect may lead are considered. According to the analysis of statistical data obtained from enterprises engaged in engine repair, an increase in defects of residual deformation of deflections was noted. The necessity of collecting and systematizing cases of curvature of the longitudinal axis above the permissible value is determined. The conditions for preparing shafts for defecation have been clarified. Attention is drawn to the need to take into account the results of previous measurements and the total operating time of the engine when laying the shaft approved for further operation. The object of the study is the crankshaft of the diesel engine 6 CHN 31.8/33, used in water transport as the main marine engine. Measurements of the radial runout of twenty shafts that received deflection were made. The dependence of the measurement error on the radius of the shaft neck is established. A histogram of the frequency distribution of deflections of the crankshaft frame necks depending on the repair size number is constructed and the dependence of the deflection frequency on the repair size number is illustrated. The maximum deflection of the crankshaft of 4.10 mm with an allowable deflection of 0.03 mm is fixed. The values of deflections of diesel shafts are analyzed, their dependence on the number of the repair size and the number of the frame neck on which the deflection occurred. The frequency and significant increase in the magnitude of the deflection arrow on the fourth frame neck were noted. The necessity of using the obtained statistical data on deflections for the scientific substantiation of the technology of correction of diesel krancshafts is determined.
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Diana, Willis. "Perbandingan Analisis Lendutan Pelat dengan Menggunakan Metode Beam on Elastic Foundation (BoEF) dan Finite Element Method (FEM)." Semesta Teknika 14, no. 1 (December 16, 2015): 94–100. http://dx.doi.org/10.18196/st.v14i1.590.
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The aim of this study was to compare deflection plates are supported by soil by using the method of Beam on Elastic Foundation (BoEF) and Finite Element Method (FEM). To validated the methods, used data from laboratory testing of the loading plate models. For the calculation of deflection plates on elastic (soil) foundation, the accuracy of determining the modulus of subgrade reaction will greatly affect the calculation of deflection plate. Deflection calculation used Finite Element Method and BoEF method gave deflections, where close enough to those of experimental result. Both methods can be used to estimate the plate deflection.
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He, Xian Long, Tian Li She, and Li Zhen Zhao. "A New System for Dynamic Deflection Measurement of Highway Bridge." Applied Mechanics and Materials 226-228 (November 2012): 1645–50. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1645.
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The bridge deflection measurement is an important component to the bridge examination and a important target to the security appraises. Using Slope sensor to test the Dynamic deflection is a good way for highway bridge deflection detection. In this paper, we develop a new slope sensor and new theory to fast calculate deflection from slope angle. It has been use to detect the dynamic deflections of songhuajiang bridge on Harbin-Changchuen highway when car cross at kinds of speed. The test result indicates: comparing with the measurement results of photoelectric deflection detection system, the dynamic deflection measurement results of slope sensors are much closed. Their deflection curves are also similar. The result also shows: Using our slope sensors to test highway bridge dynamic deflection can get precise results and can satisfy the highway bridge deflection testing request. It is also very easy to use. You can finish the testing easily and do not stop the traffic.
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Loganathan, Karthikeyan, Mayzan Isied, Ana Maria Coca, Mena Souliman, Stefan Romanoschi, and Samer Dessouky. "Development of Deflection Parameters to Evaluate the Structural Capacity of Flexible Pavements at the Network Level: Case Study for the State of Texas." MATEC Web of Conferences 271 (2019): 08003. http://dx.doi.org/10.1051/matecconf/201927108003.
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Pavement deflection has been used widely as a nondestructive technique to evaluate the structural capacity of pavements at both network and project levels. Various transportation agencies use several evaluation methods to evaluate the integrity of the pavement layers. Most of these up-to-date developed indices are exclusively based on either central deflections or one deflection point along FWD deflection bowl. However, no standardized method that utilizes the full FWD deflection bowl is available. This study aims to introduce new comprehensive pavement layer deflection and deflection bowl area parameters that are based on the entire FWD deflection bowl rather than one single deflection point and to relate the developed parameters to the field measured distress data. Thirty-five different pavement sections in the State of Texas were utilized in the study. Two comprehensive deflection parameters and a ranking scale were developed that may be utilized for the overall pavement structural condition evaluation.
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Saxena, A., and S. N. Kramer. "A Simple and Accurate Method for Determining Large Deflections in Compliant Mechanisms Subjected to End Forces and Moments." Journal of Mechanical Design 120, no. 3 (September 1, 1998): 392–400. http://dx.doi.org/10.1115/1.2829164.
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Compliant members in flexible link mechanisms undergo large deflections when subjected to external loads. Because of this fact, traditional methods of deflection analysis do not apply. Since the nonlinearities introduced by these large deflections make the system comprising such members difficult to solve, parametric deflection approximations are deemed helpful in the analysis and synthesis of compliant mechanisms. This is accomplished by representing the compliant mechanism as a pseudo-rigid-body model. A wealth of analysis and synthesis techniques available for rigid-body mechanisms thus become amenable to the design of compliant mechanisms. In this paper, a pseudo-rigid-body model is developed and solved for the tip deflection of flexible beams for combined end loads. A numerical integration technique using quadrature formulae has been employed to solve the large deflection Bernoulli-Euler beam equation for the tip deflection. Implementation of this scheme is simpler than the elliptic integral formulation and provides very accurate results. An example for the synthesis of a compliant mechanism using the proposed model is also presented.
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Lee, Soo-Hyun, and Daniel J. Simons. "Angular Tuning and Velocity Sensitivity in Different Neuron Classes Within Layer 4 of Rat Barrel Cortex." Journal of Neurophysiology 91, no. 1 (January 2004): 223–29. http://dx.doi.org/10.1152/jn.00541.2003.
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Local circuitry within layer IV whisker-related barrels is preferentially sensitive to thalamic population firing synchrony, and neurons respond most vigorously to stimuli, such as high-velocity whisker deflections, that evoke it. Field potential recordings suggest that thalamic barreloid neurons having similar angular preferences fire synchronously. To examine whether angular tuning of cortical neurons might also be affected by thalamic firing synchrony, we characterized responses of layer IV units to whisker deflections that varied in angular direction and velocity. Barrel regular-spike units (RSUs) became more tuned for deflection angle with slower whisker movements. Deflection amplitude had no affect. Barrel fast-spike units (FSUs) were poorly tuned for deflection angle, and their responses remained constant with different deflection velocity. The dependence of angular tuning on deflection velocity among barrel RSUs appears to reflect the same underlying response dynamics that determine their velocity sensitivity and receptive field focus. Unexpectedly, septal RSUs and FSUs are largely similar to their barrel counterparts despite available evidence suggesting that they receive different afferent inputs and are embedded within different local circuits.
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Šmejkal, Jiří, and Jaroslav Procházka. "Design of Ceiling Structures with Regards to Deflection." Solid State Phenomena 249 (April 2016): 241–45. http://dx.doi.org/10.4028/www.scientific.net/ssp.249.241.
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The standard EN 1992-1-1 [1] provides two approaches to limiting deflection of ceiling structures. One approach is limitation of bending slenderness using simple formulas. The second approach is the direct calculation of deflection. In the paper, there are analyzed restrictive conditions for the use of limited bending slenderness. Further there are design approaches for determining deflections of conventional floor building structures. Then there is mentioned the solution of estimating of total deflection from the linear FEM calculations. Information on other methods of determining the deflection of ceiling structures is given in the end.
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Chen, Ming Jun, Zhi Jun Wang, Chun Ya Wu, and Hai Bo Ni. "Research on the Influence Factors for the Deflection of Micro-Ball-End Cutter in Micro-End-Milling Process." Materials Science Forum 697-698 (September 2011): 84–87. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.84.
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Machining parameters and spindle radial runout have great influence on the micro-ball-end cutter deflection in the micro-end-milling process. In this study, a 3D (three-dimensional) thermal-mechanical FEM (finite element method) model of micro-milling with non-rigid cutter is built to study how radial runout, cutting depth, feed and spindle speed influence the cutter deflection when feed has the same direction with the spindle radial runout. Cutter deflection under different groove lengths, cutting depths, feeds and spindle speeds is investigated, which shows that cutter deflection increases with spindle radial runout significantly. The largest deflections with runout of 2μm are 3.26μm, 3.26μm, 4.71μm and 4.52μm respectively under the adopted machining conditions, while the largest deflections without runout are 1.85μm, 1.85μm, 2.26μm and 3.79μm respectively. It is also shown that the runout effect increases with groove length, cutting depth, while it decreases with feed.
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Kim, Sun-Hee, Soon-Jong Yoon, and Wonchang Choi. "Experimental Study on Long-Term Ring Deflection of Glass Fiber-Reinforced Polymer Mortar Pipe." Advances in Materials Science and Engineering 2019 (March 3, 2019): 1–10. http://dx.doi.org/10.1155/2019/6937540.
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Long-term pressurizing of buried glass fiber-reinforced polymer (GFRP) pipe will result in the reduction of stiffness in the pipes. It leads to excessive deflections in long-term design limits. In situ tests were performed for 664 days to measure deflections of buried GFRP pipe with a large diameter of 2,400 mm. Based on the field test results, finite element analysis was conducted to determine the pipe deflections with respect to the soil conditions and buried depth as variables. Regression analysis has been conducted to determine the long-term deflection of the GFRP pipe after 50 years of construction. The long-term deflection of the GFRP pipe was less than 5 percent suggested by the existing specifications including ASTM D5365 and AWWA M45. The comparison indicates the current specifications significantly conservative to predict long-term deflection of the buried GFRP pipe.
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Estes, M., E. Wang, and M. L. Hull. "Analysis of Ankle Deflection During a Forward Fall in Snowboarding." Journal of Biomechanical Engineering 121, no. 2 (April 1, 1999): 243–48. http://dx.doi.org/10.1115/1.2835110.
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Toward the general goal of preventing ankle injuries in snowboarding accidents, the objective of this project to develop a dynamic system model of a snowboarder and assess which model parameters, particularly those attributed to the boot, most strongly influenced ankle deflections during a forward fall. To satisfy this objective, a system model was created that included the rider, the boots, the snowboard, and the snow as components. Through dynamic simulations, peak ankle deflections were computed over realistic ranges of input parameter values for each of the model components. Defining sensitivity as the total change in peak ankle deflection over the range of a particular parameter studied, results indicated that the peak ankle deflection was most sensitive to the boot stiffness. Although lower, the sensitivity of the peak ankle deflection to the snow model parameters was still significant, being roughly half of the boot sensitivity. Increases in both snow stiffness and snow damping caused higher ankle deflections. Variations in both snowboard stiffness and anthropometric parameters had little effect. Due to the strong dependence of ankle deflection on boot stiffness, the potential exists for mitigating the ankle injury problem through judicious design of the boot.
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Choudary, Dhanyabiram, Poornima Jnaneshwar, and Ravi Kannan. "EVALUATION AND COMPARISON OF LOAD DEFLECTION RATE OF FOUR INITIAL ORTHODONTIC ARCH WIRES: AN IN VITRO STUDY." International Journal of Orthodontic Rehabilitation 13, no. 3 (September 6, 2022): 1–9. http://dx.doi.org/10.56501/intjorthodrehabil.v13i3.18.
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Aim: The aim of this study was to evaluate the load-deflection rate of four different types of archwires used in initial stage of orthodontic treatment.
Materials and methods: A modified three-point bending test was performed on the sample of 60 wires of superelastic Nickel Titanium(NiTi), everwhite esthetic NiTi, thermal NiTi and multistranded coaxial stainless steel (15 each). The load exerted by each of the wire was measured at the deflections of 2 mm and 4mm, subsequent unloading process at 37°C temperature.
Results: Comparison of mean load-deflection values revealed that thermal NiTi wires had lowest value at both 2 and 4mm deflection when compared to other three wires which was statistically significant(p=0.009). Superelastic and esthetic NiTi showed similar values of load deflection ratios at both the deflections where as co-axial wire showed 1.89N at 2mm and 5.22N at 4mm deflection.
Conclusion: The heat-activated NiTi wires are acceptable in severe crowding and periodontally compromised patients. Multistranded co-axial wire is acceptable when we need minimal alignment; whereas esthetic NiTi wires can replace superelastic Niti based on patient’s need.
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Fu, Guozhi, Cheng Xue, Yanqing Zhao, Dandan Cao, and Mohsen Alae. "Accuracy evaluation of statically backcalculated layer properties of asphalt pavements from falling weight deflectometer data." Canadian Journal of Civil Engineering 47, no. 3 (March 2020): 317–25. http://dx.doi.org/10.1139/cjce-2019-0152.
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This study is to evaluate the dynamic effects of falling weight deflectometer (FWD) loading on the surface deflection of asphalt pavement and the accuracy of statically backcalculated layer moduli from FWD data. The dynamic and static deflections were computed using the spectral element method and the layer elastic theory, respectively, for various pavement structures. The static deflection is considerably larger than the dynamic deflection for typical FWD loading and the normalized difference between static and dynamic deflections increases with increasing distance from the load center and decreases with increasing loading duration. The dynamic deflections were utilized to backcalculate the layer moduli using two static backcalculation procedures, MODULUS and EVERCALC. The backcalculated moduli can be significantly different from the actual moduli. The results indicate that the static backcalculation procedure can lead to significant errors in the backcalculated layer moduli by ignoring the dynamic effects of FWD loading.
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Pratomo, Harris Gadih, Endah Mardiati, Eky Soeria Soemantri, and Ida Ayu Evangelina. "Deflection test on different orthodontic wire materials sized 0.016 x 0.022 inches." Majalah Kedokteran Gigi Indonesia 4, no. 3 (September 6, 2019): 142. http://dx.doi.org/10.22146/majkedgiind.31236.
Full textAbstract:
The development of technology in orthodontic field produces some orthodontic wires that have different deflection abilities. Loading force is the force needed to place an orthodontic wire in bracket slot (activation). Unloading force is the force produced by an orthodontic wire to move tooth (deactivation). Deflection test with three-point bending technique is a technique that is often used to determine the magnitude of the activation and deactivation force of orthodontic wire. Stainless steel (SS), nickel titanium (NiTi), copper nickel titanium (CuNiTi), and beta titanium (TMA), are the types of frequently used wires. This study aimed to compare loading and unloading force on the deflection test of SS, NiTi, CuNiTi, and TMA orthodontic wires sized 0.016 x 0.022 inch on the load-deflection graph. This is a laboratoryexperimental research on a total of 16 pieces of SS, NiTi, CuNiTi, and TMA orthodontic wires sized 0.016 x 0.022 inches. The group was divided based on the type of material. The deflection test was performed using a universal testing machine with a press speed of 5 mm/minute. Loading and unloading forces were recorded on deflections of 0.5; 1; and1.5 mm. Statistical tests of differences among groups were carried out by ANOVA analysis (p-value ≤ 0.05) and post-hoc analysis with T-test. There were significant differences in the loading and unloading forces recorded on deflections of 0.5; 1; and 1.5 mm; except for deflections of 0.5 mm of the SS and nickel-titanium wires. The wire deflection force fromthe lowest to the highest was CuNiTi wire, nickel-titanium wire, TMA wire, and stainless-steel wire.
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Drew, Patrick J., and Daniel E. Feldman. "Representation of Moving Wavefronts of Whisker Deflection in Rat Somatosensory Cortex." Journal of Neurophysiology 98, no. 3 (September 2007): 1566–80. http://dx.doi.org/10.1152/jn.00056.2007.
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Rats rhythmically sweep their whiskers over object features, generating sequential deflections of whisker arcs. Such moving wavefronts of whisker deflection are likely to be fundamental elements of natural somatosensory input. To determine how moving wavefronts are represented in somatosensory cortex (S1), we measured single- and multiunit neural responses in S1 of anesthetized rats to moving wavefronts applied through a piezoelectric whisker deflector array. Wavefronts consisted of sequential deflections of individual whisker arcs, which moved progressively across the whisker array. Starting position (starting arc), direction, and velocity of wavefronts were varied. Neurons responded strongly only when wavefront starting position included their principal whisker (PW). When wavefronts started at neighboring positions and swept through the PW, responses to the PW arc were suppressed by ≤95%, and responses over the entire wavefront duration were suppressed by ≤60% compared with wavefronts that initiated with the PW. Suppression occurred with interarc deflection delays of ≥5 ms, was maximal at 20 ms, and recovered within 100–200 ms. Suppression of PW arc responses during wavefronts was largely independent of wavefront direction. However, layer 2/3 neurons showed direction selectivity for responses to the entire wavefront (the entire sequence of SW and PW arc deflection). Wavefront direction selectivity was correlated with receptive field somatotopy and reflected differential responses to the specific SWs that were deflected first in a wavefront. These results indicate that suppressive interwhisker interactions shape responses to wavefronts, resulting in increased salience of wavefront starting position, and, in some neurons, preference for wavefront direction.
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Han, Jihuan, Jiuqun Zou, Chenchen Hu, and Weihao Yang. "Deflection Mechanism and Safety Analysis of Coal Mine Shaft in Deep Soil Strata." Mathematical Problems in Engineering 2019 (December 5, 2019): 1–11. http://dx.doi.org/10.1155/2019/9461742.
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The main shaft and auxiliary shaft in the Guotun Coal Mine underwent large deflections, with deflection values of 359 mm and 322 mm, respectively. These two deflections represent the first occurrence of such large vertical shaft deviations in the soil strata in China. The deflection problem has seriously affected the hoisting safety and lining safety and has become a serious impediment to the sustainable production of mines. Therefore, the deflection mechanism must be determined. For this purpose, based on mining subsidence theory, the spatial probability integral method and a more accurate time function were used to establish a model, called 3D dynamic prediction model, for predicting the shaft movement. The formulas for calculating the lining stress caused by coal mining were based on established models. With measured shaft deflection data, the prediction parameters for deep soil strata were calculated on the basis of an inversion analysis. A comparative analysis of measured and calculated deflection values revealed that the reason for shaft deflection in Guotun Coal Mine is the insufficient size of the protection coal pillar (PCP); namely, the design parameters of the PCP in current codes are not applicable to the deep soil strata. As a result, under the asymmetric mining conditions, mining causes the shaft to deflect without damage and under the symmetric mining conditions, mining causes the lining to fracture. The results have an extremely important significance for the prevention and control of shaft deflection, for the rational design of PCP, and for the sustainability of mine production.
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Bay, James A., Kenneth H. Stokoe, Michael T. McNerney, Suttisak Soralump, David A. Van Vleet, and Dan K. Rozycki. "Evaluating Runway Pavements at Seattle-Tacoma International Airport: Continuous Deflection Profiles Measured with the Rolling Dynamic Deflectometer." Transportation Research Record: Journal of the Transportation Research Board 1716, no. 1 (January 2000): 1–9. http://dx.doi.org/10.3141/1716-01.
Full textAbstract:
The rolling dynamic deflectometer (RDD) is a relatively new tool for assessing the condition of pavements. Continuous deflection profiles, rather than deflections at discrete points, are measured with the RDD. The results of RDD tests on two runways at the Seattle-Tacoma International Airport (Sea-Tac) are presented. These results illustrate how continuous deflection profiles can be used to assess the condition of pavements without the use of backcalculation. Continuous deflection profiles allow sections of pavement exhibiting large or anomalous deflections to be quickly and easily identified. The extent to which pavements are damaged and degraded can be determined by comparison of the deflections of intact, lightly trafficked pavements with the deflections of the pavements in question. The condition and load transfer capacity of all transverse joints and cracks in rigid pavements can be determined by observation of the measured deflections as the RDD approaches and crosses each joint or crack. The RDD is a valuable tool for rapidly identifying regions of pavement requiring rehabilitation. Critical regions of pavement identified with the RDD for possible rehabilitation can be studied further with use of traditional discrete testing methods. These capabilities make the RDD a valuable tool in airfield pavement management.
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Sherif, Alaa G., and Walter H. Dilger. "Analysis and deflections of reinforced concrete flat slabs." Canadian Journal of Civil Engineering 25, no. 3 (June 1, 1998): 451–66. http://dx.doi.org/10.1139/l97-102.
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The results of a test on a full-scale 5 m continuous slab are used to study the methods of analysis and calculation of deflection of reinforced concrete flat slabs. The most commonly used methods for the analysis of flat slabs, namely the equivalent frame method, the prismatic member method, the direct design method, and the finite element method, are critically compared using the results of the slab tested. Based on the comparison with the unbalanced column moments in the test, improvements for the prismatic member method are suggested. For the deflection calculations of cracked reinforced concrete flexural members, three methods are investigated: the effective moment of inertia approach, the mean curvature approach, and the bilinear method given in the CEB manual for deflections. To calculate the deflections of flat slabs as column and field strip deflections, new coefficients for distributing the bending moments between the column and middle strips are proposed.Key words: analysis, deflection, flat concrete slab, test.
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Starreveld, Roeliene, Paul Knops, Maarten Roos-Serote, Charles Kik, Ad J. J. C. Bogers, Bianca J. J. M. Brundel, and Natasja M. S. de Groot. "The Impact of Filter Settings on Morphology of Unipolar Fibrillation Potentials." Journal of Cardiovascular Translational Research 13, no. 6 (May 14, 2020): 953–64. http://dx.doi.org/10.1007/s12265-020-10011-w.
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AbstractUsing unipolar atrial electrogram morphology as guidance for ablative therapy is regaining interest. Although standardly used in clinical practice during ablative therapy, the impact of filter settings on morphology of unipolar AF potentials is unknown. Thirty different filters were applied to 2,557,045 high-resolution epicardial AF potentials recorded from ten patients. Deflections with slope ≤ − 0.05 mV/ms and amplitude ≥ 0.3 mV were marked. High-pass filtering decreased the number of detected potentials, deflection amplitude, and percentage of fractionated potentials (≥ 2 deflections) as well as fractionation delay time (FDT) and increased percentage of single potentials. Low-pass filtering decreased the number of potentials, percentage of fractionated potentials, whereas deflection amplitude, percentage of single potentials, and FDT increased. Notch filtering (50 Hz) decreased the number of potentials and deflection amplitude, whereas the percentage of complex fractionated potentials (≥ 3 deflections) increased. Filtering significantly impacted morphology of unipolar fibrillation potentials, becoming a potential source of error in identification of ablative targets.
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Ma, Chi, Shi-zhong Liu, Jin Di, and Rui-jie Zhang. "Analysis of Pure Bending Vertical Deflection of Improved Composite Box Girders with Corrugated Steel Webs." Advances in Civil Engineering 2021 (March 30, 2021): 1–13. http://dx.doi.org/10.1155/2021/6617846.
Full textAbstract:
Steel bottom plates are applied as replacements for the concrete bottom plates in order to reduce the dead weight of the composite box girders with corrugated steel webs and steel bottom plates (CSWSB). Due to the change in the material, the previous analytical calculation methods of vertical deflection of composite box girders with corrugated steel webs (CSWs) cannot be directly applied to the improved composite box girders. The shear lag warpage displacement function was derived based on the shear deformation laws of the upper flange and the bottom plates of the improved composite box girders. The equations for the calculation of the shear deformation and the additional deflection due to the shear lag of continuous and simply supported composite box girders with CSWSB under concentrated and uniformly distribution loads were derived by considering the double effects of the shear lag and the shear deformations of the top and the bottom plates with different elastic moduli. The analytical solutions of the vertical deflection of the improved composite box girders include the theory of the bending deflection of elementary beams, shear deformation of CSWs, and the additional deflection caused by the shear lag. Based on the theoretical derivation, an analytical solution method was established and the obtained vertical deflection analytical solutions were compared with the finite element method (FEM) calculation results and the experimental values. The analytical equations of vertical deflection under the two supporting conditions and the two load cases have verified the analyses and the comparisons. Further, the additional deflections due to the shear lag and the shear deformation are found to be less than 2% and 34% of the total deflection values, respectively. Moreover, under uniform distributed load conditions, the deflection value was found to be higher than that of the under concentrated load condition. It was also found that the ratio of the deflection caused by the shear lag or the shear deformation to the total deflection decreased gradually with the increase in the span width ratio. When the value of the span width ratio of a single box and single chamber composite box girder with CSWSB was equal to or greater than 8, the deflections caused by the shear lag and the shear deformation could be ignored.
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Ba, Makhaly, Meissa Fall, and Oustasse Abdoulaye Sall. "Deflection characteristics of Unbound Base Course During a Large Scale Model Experiment." Studies in Engineering and Technology 2, no. 1 (February 9, 2015): 1. http://dx.doi.org/10.11114/set.v2i1.595.
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This paper evaluates de deflections (measured at the surface and/or at the top of the subgrade) of unbound pavement materials under cyclic loading. Deflections of three base course materials (Bakel Red Quartzite, Bakel Black Quartzite and Diack Basalt) were investigated using a large-scale model experiment (LSME). The LSME is a prototype-scale pavement test apparatus where cyclic loading is applied and deflections are measured. The LSME replicates field conditions and accounts for scale effects. The LSME results showed that the total, plastic and net plastic deflections of a pavement increase progressively as the number of loading cycles increases. The total deflection decreases as the thickness of the base layer increases. Plastics deflections at the top of the subgrade decrease progressively as the thickness of the base layer is increased. The elastic deflections of the surface and of the base layer decrease gradually with the increasing loading cycles. The elastic deflection at the top of the subgrade decreases with increasing thickness of the base layer. So, rutting can be limited by limiting the elastic deflection at the top of the subgrade. However, this criterion does not account for the rutting caused by the unbound base layers and that of the asphalt concrete.
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LIU, WANYU, ZHIYONG YANG, and SHAN JIANG. "A MECHANICS-BASED MODEL FOR SIMULATING THE NEEDLE DEFLECTION IN TRANSVERSE ISOTROPIC TISSUE FOR A PERCUTANEOUS PUNCTURE." Journal of Mechanics in Medicine and Biology 19, no. 06 (September 2019): 1950060. http://dx.doi.org/10.1142/s021951941950060x.
Full textAbstract:
During the percutaneous puncture for robot-assisted brachytherapy, a medical needle is usually inserted into fiber-structured soft tissue which has transverse isotropic elasticity, such as muscle and skin, to deliver radioactive seeds that kill cancer cells. To place the radioactive seeds more accurately, it is necessary to assess the effect of the transverse isotropic elasticity on the needle deflection. A mechanics-based model for simulating the needle deflection in transverse isotropic tissue is developed in this paper. The anisotropic needle–tissue interaction forces are estimated and used as inputs to drive the model for simulating needle deflections for different insertion orientation angles. Automatic insertion experiments were performed on a single-layered porcine muscle at five different insertion orientation angles. The results show that the maximum difference in the tip deflection for the different insertion orientation angles is 2.99[Formula: see text]mm when the insertion depth is 50[Formula: see text]mm. The maximum simulated error of the needle axis deflection is 0.62[Formula: see text]mm for all insertion orientation angles. The developed model can successfully simulate the needle deflections inside transverse isotropic tissue for different insertion orientation angles. This work is useful for predicting and compensating for the deflection error for automatic needle insertion.
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Sung, Yoon-Gyung, and Chang-Lae Kim. "Deflection Reduction Shaping Commands with Asymmetric First-Order Actuators." Applied Sciences 9, no. 19 (September 23, 2019): 3982. http://dx.doi.org/10.3390/app9193982.
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In this paper, two approaches for generating deflection reduction shaping commands are proposed to reduce the transient and residual deflections of flexible systems subject to asymmetric first-order actuators. The commands are limited-state in that they consist of two positive actuations of different magnitudes and one negative actuation, similar to on-off-on commands. Standard on–off commands that are commonly used in robots, cranes, and spacecrafts can degrade the control performance of conventional input-shaped commands and cause detrimental damage resulting from large transient deflections of flexible structures due to asymmetric first-order actuators. Therefore, to cope with the performance degradation resulting from the effects of first-order actuators, an approximated closed-form solution and a numerically optimized approach for deflection reduction shaping commands are presented with an exponential function, final impulse magnitude modification of an input shaper is determined by a transient deflection constraint and a phasor vector approach. The performance assessment showed that the approximated analytical approach has an advantage in real-time control applications. The characteristics of the proposed deflection reduction shaping commands are analyzed with respect to system parameters, deflection reduction ratios, and actuator time constants. The proposed command shaping techniques are numerically evaluated using a pendulum system and are experimentally validated on a mini-bridge crane.
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Costa, Yuri Daniel Jatoba, John Gurgel, Carina Maia Lins Costa, and Olavo Francisco Santos. "Deflection Analysis of Anchored Retaining Wall in Dune Sand." Applied Mechanics and Materials 405-408 (September 2013): 101–5. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.101.
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This paper investigates the behavior of a 15-m high multi-anchored bored pile wall built in a dune sand overlying a naturally occurring lateritic soil layer. A parametric study using the finite element method was carried out to model wall deflections and ground movements during construction phases. Deflection results from the numerical simulations were compared to data collected in the field. The maximum horizontal wall deflection shows a non-linear decreasing trend with increasing system stiffness. Embedment length was found to play a secondary role on wall deflections. Predicted horizontal wall deflections after preloading of second and third anchor layers were on average 30% smaller than the corresponding field values.
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Han, Bing, Cheng Zu Ren, X. Y. Yang, and Guang Chen. "Experiment Study on Deflection of Aluminum Alloy Thin-Wall Workpiece in Milling Process." Materials Science Forum 697-698 (September 2011): 129–32. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.129.
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The deflection of Aluminum alloy thin-wall workpiece caused by the milling force leads to additional machining errors and reduces machining accuracy. In this paper, a set of experiments of milling thin-wall workpiece were carried out to study the deflection of thin-wall workpiece. The workpieces, with different types of material and different thicknesses, were machined on CNC machining center. The deflections of workpiece were measured by a three-coordinate measuring machine. Effects of Aluminum alloy material and thickness on deflection are discussed based on the experimental data.
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Zhou, W., and T. Kokai. "Deflection calculation and control for reinforced concrete flexural members." Canadian Journal of Civil Engineering 37, no. 1 (January 2010): 131–34. http://dx.doi.org/10.1139/l09-121.
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A methodology was proposed to calculate the incremental deflection of reinforced concrete flexural members for the purpose of protecting nonstructural elements. The methodology is based on the long-term deflection calculation equation provided in the current Canadian standard, CSA A23.3–04, and takes into account realistic load application sequence during construction. Based on the proposed methodology, simple equations for calculating the incremental deflections were derived. The use of the proposed equations is demonstrated through a realistic design example. Implications of construction load and camber for deflection calculation and control are also discussed.
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Bahrani, Natasha, Juliette Blanc, Pierre Hornych, and Fabien Menant. "Alternate Method of Pavement Assessment Using Geophones and Accelerometers for Measuring the Pavement Response." Infrastructures 5, no. 3 (March 1, 2020): 25. http://dx.doi.org/10.3390/infrastructures5030025.
Full textAbstract:
Pavement instrumentation with embeddable in-situ sensors has been a feasible approach to determine pavement deteriorations. Determining pavement deflections during the passage of the load is a promising strategy to determine the overall performance of the pavement. There are different devices that apply loads to the pavements and measure the deflection basin, these include static, vibratory, or impulse loadings. Most commonly used are the static loading like Benkelman beam and impulse loading like the Falling Weight Deflectometer (FWD). However, these techniques are costly and the measurements are recorded infrequently, i.e., once per year or two years. This study focuses on the use of geophones and accelerometers to measure the surface deflections under traffic loading. To develop a method to measure pavement deflections, the sensors were submitted first to laboratory tests, and then tested in situ, in a full scale accelerated pavement test. In the laboratory, the sensors were submitted to different types of loading using a vibrating table. These tests were used to determine the noise and sensitivity of the sensors, and then to evaluate their response to signals simulating pavement deflections under heavy vehicles. The sensor response was compared with measurements of a reference displacement sensor. Different processing techniques were proposed to correct the measurements from geophones and accelerometers, in order to obtain reliable deflection values. Then, the sensors were evaluated in a full scale accelerated test, under real heavy axle loads. Tests were performed at different loads and speeds, and the deflection measurements were compared with a reference anchored deflection sensor. The main advantage of using accelerometers or geophones embedded in the pavement is to enable continuous pavement monitoring, under real traffic. The sensor measurements could also be used to determine the type of vehicles and their corresponding speeds. The study describes in detail the signal analysis needed to measure the pavement deflections accurately. The measurements of pavement deflection can be then used to analyze the pavement behavior in the field, and its evolution with time, and to back-calculate pavement layer properties.
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Kartal, Saruhan, Ilker Kalkan, Ahmet Beycioglu, and Magdalena Dobiszewska. "Load-Deflection Behavior of Over- and Under-Reinforced Concrete Beams with Hybrid FRP-Steel Reinforcements." Materials 14, no. 18 (September 16, 2021): 5341. http://dx.doi.org/10.3390/ma14185341.
Full textAbstract:
The present study pertains to the load-deflection behavior and cracking moments of concrete beams with hybrid FRP-steel reinforcement. Under and over-reinforced hybrid beams were tested for failure along with reference beams with only steel or FRP reinforcement. The first-cracking moments of the beams were estimated analytically by using different uncracked moments of the inertia and modulus of rupture definitions. The uncracked moment of inertia definitions include the gross and uncracked transformed moments. The adopted modulus definitions are comprised of the experimental values from tests on prisms and the analytical values from the equations in different concrete codes. Furthermore, analytical methods were developed for estimating the deflections of concrete beams with hybrid FRP-steel or only FRP reinforcement. Two different types of elastic moduli, namely the secant modulus corresponding to the extreme compression fiber strain and the ACI 318M-19 modulus, were used in deflection calculations. Closer estimates were obtained by using the secant modulus, particularly in hybrid-reinforced beams. In the post-yielding region of the steel tension reinforcement, the deflection estimates were established to lay in closer proximity to the experimental curve when obtained by adding up the deflection increments instead of directly calculating the total deflections from the elastic curve equation. Accurate estimation of the cracking moment was found to be vital for the close prediction of deflections.
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Fergani, Omar, Ali Mamedov, Ismail Lazoglu, Jian Guo Yang, and Steven Y. Liang. "Prediction of Residual Stress Induced Distortions in Micro-Milling of Al7050 Thin Plate." Applied Mechanics and Materials 472 (January 2014): 677–81. http://dx.doi.org/10.4028/www.scientific.net/amm.472.677.
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In this paper, a new analytical model based on a mechanistic force prediction and elastoplastic relaxation procedure predicting the deflections induced by the residual stresses in a milled micro part is proposed. The force model defines the Hertzian type distribution applied by the tool on the part. The proposed deflection model is valid for thin rectangular parts typically produced only using a micro-milling process. The deflection and the force model were analytically developed and experimentally tested on thin Al 7050 micro plates. The force model was validated using micro dynamometer and the deflection profile was verified using the white light interferometer. The proposed model showed that it has a reasonable ability to predict the residual stress induced deflection in the context of stress gradient and intensity.
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Webber, Roxanna M., and Garrett B. Stanley. "Nonlinear Encoding of Tactile Patterns in the Barrel Cortex." Journal of Neurophysiology 91, no. 5 (May 2004): 2010–22. http://dx.doi.org/10.1152/jn.00906.2003.
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Cells in the rodent barrel cortex respond to vibrissa deflection with a brief excitatory component and a longer suppressive component. The response to a given deflection is thus scaled because of suppression induced by a preceding deflection, causing the neuronal response to be linked to the temporal properties of the peripheral stimulus. A paired-deflection stimulus was used to characterize the postexcitatory suppression and a 3-deflection stimulus was used to investigate the nonlinear response to patterns of whisker deflections in barbiturate-anesthetized Sprague–Dawley rats. The postexcitatory suppression was not dependent on a sensory-evoked action potential to the first deflection, implying that it is likely a subthreshold property of the network. The suppression induced by a deflection served to suppress both the excitatory and suppressive components of a subsequent neuronal response, thus effectively disinhibiting it. Two different response properties were observed in the recorded cells. Approximately 65% responded to a vibrissa deflection with an excitatory component followed by a suppressive component and 35% responded with excitation, suppression, and a subsequent rebound in excitation. Based on these observations of postexcitatory dynamics, a prediction method was used to estimate neuronal responses to more complex stimulus trains. Using the 2nd-order representation obtained from the paired-deflection stimulus, responses to general periodic deflection patterns were well predicted. A higher cutoff frequency was predicted for rebound cells compared with cells not exhibiting rebound excitation, consistent with experimental observations. The method also predicted the response of neurons to a random aperiodic deflection pattern. Therefore the temporal structure of cortical dynamics after a single deflection dictates the response to complex temporal patterns, which are more representative of stimuli encountered under natural conditions.
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He, Wen-Yu, Wei-Xin Ren, Lei Cao, and Quan Wang. "FEM Free Damage Detection of Beam Structures Using the Deflections Estimated by Modal Flexibility Matrix." International Journal of Structural Stability and Dynamics 21, no. 09 (May 19, 2021): 2150128. http://dx.doi.org/10.1142/s0219455421501285.
Full textAbstract:
The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.
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Ge, Chang. "Numerical Simulation of Vibration Deflection Effects on the Energy Efficiency of Ultrasonic Transducer for Sonochemistry." Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/591352.
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The energy efficiency of ultrasound transducers for sonochemistry applications was studied from the point of view of vibration deflection effects of different transducer structures, including the configurations of rectangular plate, cylindrical shell, triangular strip array, rectangular strip array, and pentagonal strip array. It was found that the deflections are not uniform over the transducer surface with the maximum deflection locating at the geometry center of transducers. The simulated maximum deflection of rectangular plate results in the value of2.5×10-16, which is larger than the maximum deflection of cylindrical shell with the value of2×10-16. This finding suggests that the envelope deflection volume of two transducers has significant difference, which has been neglected in the design and selection of ultrasound transducer. For this reason, a quantitative index involving the envelope deflection volume was proposed to compare the efficiency of ultrasound transducers. Based on the simulation results, the triangular strip array transducer structure with higher ultrasound generation efficiency was proposed, which was also theoretically validated by the MATLAB simulation.
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Xiang, Wei, and Yufeng Xing. "A New First-Order Shear Deformation Theory for Free Vibrations of Rectangular Plate." International Journal of Applied Mechanics 07, no. 01 (February 2015): 1550008. http://dx.doi.org/10.1142/s1758825115400086.
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A new first-order shear deformation theory (FSDT) with pure bending deflection and shearing deflection as two independent variables is presented in this paper for free vibrations of rectangular plate. In this two-variable theory, the shearing deflection is regarded as the only fundamental variable by which the total deflection and bending deflection can be expressed explicitly. In contrast with the conventional three-variable first-order shear plate theory, present variationally consistent theory derived by using Hamiltonian variational principle can uniquely define the bending and the shearing deflections, and give two rotations by the differentiations of bending deflection. Due to more restrictive geometrical constraints on rotations and boundary conditions, the obtained natural frequencies are equal to or higher than those by conventional FSDT for the rectangular plate with at least one pair of opposite edges simply supported. This new theory is of considerable significance in theoretical sense for giving a simple two-variable FSDT which is variational consistent and involve rotary inertia and shear deformation. The relation and differences of present theory with conventional FSDT and other relative formulations are discussed in detail.
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Yin, Fu Cheng, Guang Chun Zhou, and Hua Guo. "Parametric Analysis of Flexible Pavement Layers’ Accumulating Deflections." Applied Mechanics and Materials 253-255 (December 2012): 626–31. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.626.
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This paper conducted a parametric analysis of the flexible pavement layers’ accumulating deflections. The accumulating process of the full-scale medium-strength subgrade (MFC) pavement layer deflections had been simulated by the previous radial basic function (RBF) model. Based on the RBF simulation results, several parameters were proposed to investigate the accumulating features of the pavement layer thickness response, the relationship between layer deflection capacity and average layer thickness, the relationship between the average thickness values of two layers and the relationship between the maximum deflection values of two layers. The analytical results revealed some unseen features of the pavement layer deflections, which provided a new way to parametrically investigate the accumulating response of the flexible pavement layers.
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Liu, Shun Feng, Mu Yi Hou, Xiao Liu, and Ru Heng Wang. "Analysis of Cracking Moment and Immediate Deflection in FRP Rebars Reinforced Concrete Beams." Advanced Materials Research 671-674 (March 2013): 618–21. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.618.
Full textAbstract:
Fiber reinforced polymer rebars have advantages of light weight, high tensile strength and excellent corrosion resistance. However, researches showed that [1-2], the low elastic modulus of FRP rebar resulting in a larger deflection than steel reinforced concrete beam in equivalent condition. Therefore, it is crucial to control the deflections in serviceability limit states. Three GFRP reinforced concrete beams were tested with four-point bending, deducing the cracking moment formula of the FRP reinforced beam. Then, Bischoff model is adopted to calculate the deflection, and reaching a good agreement with the experimental results. We recommend Bischoff model to evaluate the immediate deflections.
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THONG, WILSON WANG-KIT, and GUANRONG CHEN. "COMPLEX DYNAMICAL BEHAVIORS OF DEFLECTION ROUTING ON GRID NETWORKS." International Journal of Bifurcation and Chaos 22, no. 07 (July 2012): 1250169. http://dx.doi.org/10.1142/s0218127412501696.
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Deflection routing is a mechanism to route packets away from congestion. Traditional shortest path routing uses only the static topological information as input, whereas deflection routing takes into account the dynamic queue length information. In the simplest form of deflection routing, a packet being dropped due to queue buffer overflow is "rescued" and is rerouted to other links. Deflection routing can thus reduce the rate of packet drops and allow a network to carry more packets without the need of additional bandwidth. However, it can also lead to unstable deflecting behavior in some congestion scenario. It is important to study deflection behavior when operating near the point of congestion. In this paper, the performance in terms of packet drop rate and traveling time are studied through extensive simulation, and complex behavior in the traffic with self-similarity property is observed and discussed.
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Ucun, Ismail, Fatih Onur Hocaoğlu, and Sukru Gorgulu. "A Time-Frequency Analysis for Deflection of a Cutting Disc Used in Sawing Process." Advanced Materials Research 268-270 (July 2011): 847–52. http://dx.doi.org/10.4028/www.scientific.net/amr.268-270.847.
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Cutting discs are affected by various forces which cause stresses and deflections on the discs. Lateral deflection is one of the most frequent. It is important to know that major lateral deflections can cause undesired failures on the disc. In this study, time/frequency analysis of deflection on a cutting disc used in metal sawing process has been performed. The deflections are measured by using a laser device called KEYENCE and data recorded during the cutting process. The data sequence is converted into frequency domain with Fourier transform techniques and frequency components are analyzed. It is observed that some frequency components carry important information about the process. Using this information, the starting and ending times of cutting are determined and presented.
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Evkin, Alexander, Maksym Kolesnikov, and Olga Lykhachova. "Buckling load prediction of an externally pressurized thin spherical shell with localized imperfections." Mathematics and Mechanics of Solids 24, no. 3 (January 29, 2018): 653–67. http://dx.doi.org/10.1177/1081286517753277.
Full textAbstract:
A simple formula for buckling load was derived from the asymptotic analysis of nonlinear behavior of a thin spherical shell. Firstly, two asymptotic cases were studied: the initial post-buckling regime of a perfect structure with small (compared to shell thickness) deflections and equilibrium states with large deflections. Two asymptotic formulae were jointed to obtain the solution for the entire range of deflection amplitude. Then the solution was modified for an imperfect shell. Initial deflections were introduced by only one parameter: the slope of the load–deflection diagram at small pressure. This minimal information was enough to predict the buckling load of the structure with localized imperfections. The suggested asymptotic result was validated by the finite element method and by comparison with experimental data.