Journal articles: 'Longitudinal force'

1

Zhou, Haichao, Huiyun Li, Jian Yang, Qingyun Chen, Guolin Wang, Tong Han, Jieyu Ren, and Te Ma. "A Strain-Based Method to Estimate Longitudinal Force for Intelligent Tires by Using a Physics-Based Model." Strojniški vestnik – Journal of Mechanical Engineering 67, no. 4 (April 26, 2021): 153–66. http://dx.doi.org/10.5545/sv-jme.2020.7068.

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Tires are essential components of vehicles and the only vehicle components in contact with the road. The tire longitudinal force originating from the contact between the tire and road can enhance traction and braking and contribute to the directional stability of vehicles. If the longitudinal tire force can be accurately estimated, vehicle safety can be improved. This study established a longitudinal tire physics-based model combining the brush model with the flexible ring model to develop a strain-based intelligent tire system for estimating the longitudinal tire force. The developed longitudinal dynamic model was used to study tire strain characteristics under pure longitudinal slip conditions. An algorithm was developed for estimating the longitudinal tire force through feature extraction and data fitting of the tire strain. A finite-element tire model was established to simulate the longitudinal force. Comparing the simulated and estimated forces indicated that the proposed algorithm can accurately predict the longitudinal force of intelligent tires and thus provide useful information to vehicle stability control systems.

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Wu, Qing, Yan Sun, Maksym Spiryagin, and Colin Cole. "Railway track longitudinal force model." Vehicle System Dynamics 59, no. 1 (October 1, 2019): 155–70. http://dx.doi.org/10.1080/00423114.2019.1673445.

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Bai, Bing, Ze Yu Wu, and Xiao Shan Deng. "Longitudinal Seismic Forces of Long-Span Bridge." Advanced Materials Research 255-260 (May 2011): 1134–37. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1134.

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Based on the numerical simulation and finite element method, the longitudinal seismic action of a long-span continuous bridge is systematically analyzed. Four load cases are considered, i.e. bridge without piers, bridge with piers, neglecting friction force and combining friction force and pier scouring respectively. Calculation results show that: when considering the piers, the contribution of piers to bridge longitudinal seismic forces is depending on the concrete problems; when the friction force of rubber supports is regarded, sliding support greatly enhances the longitudinal overall rigidity of the bridge, but the force is resolved to each rubber support and can improve the stress state of the fixed support; considering effect of scouring, the elongation of piers will lead to the decrease of longitudinal overall rigidity, thereby lowering the longitudinal seismic forces. From comparison of the two piers that, the relatively flexible structure has shock absorption to a certain extent, so it is more suitable for the bridge.

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Mokhiamar, O., and M. Abe. "Experimental verification using a driving simulator of the effect of simultaneous optimal distribution of tyre forces for active vehicle handling control." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 2 (February 1, 2005): 135–49. http://dx.doi.org/10.1243/095440705x6461.

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Both theoretical and experimental studies are carried out in order to prove the effect of the simultaneous optimum distribution of lateral and longitudinal tyre forces on enhancement of vehicle handling and stability assuming that all four wheels can be independently steered and driven/braked. A driving simulator is used as an experimental instrument to investigate the effect of the optimum tyre force distribution control. The inputs to the optimization process are the driver's commands (steering wheel angle and foot brake pressure/accelerator pedal pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tyre forces cannot be chosen arbitrarily, but must satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force and total yaw moment to achieve a given vehicle motion. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate to the driver's steering input, while the total longitudinal force is computed according to the driver's command (traction/braking). The results of either computer simulation or a driving simulator show that the influence of the proposed optimum tyre force distribution control on vehicle performance enhancement is significantly apparent. Furthermore, driving simulator results show very good agreement with the computer simulation results presented.

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Mokhiamar, Ossama, and Masato Abe. "Simultaneous Optimal Distribution of Lateral and Longitudinal Tire Forces for the Model Following Control." Journal of Dynamic Systems, Measurement, and Control 126, no. 4 (December 1, 2004): 753–63. http://dx.doi.org/10.1115/1.1850533.

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This paper presents a proposed optimum tire force distribution method in order to optimize tire usage and find out how the tires should share longitudinal and lateral forces to achieve a target vehicle response under the assumption that all four wheels can be independently steered, driven, and braked. The inputs to the optimization process are the driver’s commands (steering wheel angle, accelerator pedal pressure, and foot brake pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tire forces cannot be chosen arbitrarily, they have to satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force, and total yaw moment. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate while the total longitudinal force is computed according to driver’s command (traction or braking). A computer simulation of a closed-loop driver-vehicle system subjected to evasive lane change with braking is used to prove the significant effects of the proposed optimal tire force distribution method on improving the limit handling performance. The robustness of the vehicle motion with the proposed control against the coefficient of friction variation as well as the effect of steering wheel angle amplitude is discussed.

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Haosheng, Chen, Chen Darong, and Li Yongjian. "Investigation on Effect of Surface Roughness Pattern to Drag Force Reduction Using Rotary Rheometer." Journal of Tribology 128, no. 1 (September 16, 2005): 131–38. http://dx.doi.org/10.1115/1.2125969.

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A drag force reduction experiment is performed on polyoxyethylene (PEO) water solution using a rotary rheometer. Longitudinal, transverse, and isotropic grooves are notched on the rotor’s surface to investigate the effect of surface roughness patterns. The experiment results show that higher drag force is generated on the surface with transverse grooves compared with the drag force on a smooth surface, while lower drag force is generated on the surface with longitudinal grooves. The drag force on the surface with isotropic grooves is between them. Forces on the side wall of the grooves play important roles in drag force reduction. They are numerically analyzed based on the Navier-Stokes equation using the finite volume method. The viscous force on the groove’s bottom plane is far less than the force on the corresponding plane of the smooth surface, but the drag force on the groove’s surface is compensated either by the pressure drag on the side walls of the transverse groove or by the viscous force on the side walls of the longitudinal groove. The pressure drag on side wall of transverse groove is always higher than the viscous force on side wall of longitudinal groove. The numerical results cope with the experiment results that only the surface with longitudinal grooves can reduce the drag force.

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Petrov, Anatoliy, Andriy Paliy, Artem Naumenko, Serhii Sheptun, Maryna Ihnatenko, Ivan Vysochin, Yana Kononenko, Oksana Yurchenko, Tetiana Dedilova, and Anatoliy Paliy. "Improving the algorithm of choosing spacing and number of stiff supports against a concentrated force in steel-concrete beams." Eastern-European Journal of Enterprise Technologies 2, no. 7 (110) (April 30, 2021): 40–47. http://dx.doi.org/10.15587/1729-4061.2021.228862.

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A steel-concrete beam was taken as the study object. The algorithm of selecting the number of stiff supports for the steel-concrete beam loaded with a concentrated lateral force in the middle of the span has been refined. Stiff supports served to join the steel strip with concrete to ensure their joint performance. The algorithm was refined based on the condition of equality of the longitudinal force in the steel strip from the action of the calculated load and the maximum longitudinal force obtained after setting the supports. In this case, the longitudinal forces in all stiff supports, as well as the spacing of the stiff supports should be the same. A disadvantage of the known algorithm consists in the complexity of determining the coefficient φb2 taking into account the effect of long-term concrete creep on the element deformation without cracks. This coefficient fluctuates widely and depends on many factors. Besides, it is also insufficiently studied. Calculations for determining the number and spacing of stiff supports in a steel-concrete beam were conducted according to the proposed algorithm and in the Lira software package. The forces acting on the supports and spacing of the supports were the same. The force acting in the support was 8941.5 N. When selecting characteristics of the steel-concrete beam, maximum longitudinal force in the steel strip was obtained. The longitudinal force amounted to 35726 N. The same longitudinal force was obtained from the diagram of longitudinal forces obtained after setting the supports. This study was aimed at improving the design of steel-concrete beams. A rational number and placement of stiff supports ensure savings: the required amount of building materials is reduced and their cost is reduced due to cutting labor costs for their manufacture and operation

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Jamshidi, Rasa, and Ali A. Jafari. "Evaluating actuator distributions in simply supported truncated thin conical shell with embedded piezoelectric layers." Journal of Intelligent Material Systems and Structures 29, no. 12 (May 1, 2018): 2641–59. http://dx.doi.org/10.1177/1045389x18770905.

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In this investigation, distributed modal actuator forces of simply supported truncated conical shell embedded by a piezoelectric layer are studied. Piezoelectric layer is distributed on the conical shell surface as actuators. Three types of distributions are considered: longitudinal, circumferential, and diagonal distributions. First, electromechanical equations of the conical shell with embedded piezoelectric actuator layer are extracted. Then modal expansion method is used to define independent modal characteristics of the conical shell. For each kind of distribution, three case studies are considered and evaluated. Results showed that in the longitudinal and diagonal distributed actuator, membrane force in the longitudinal direction is the dominant force and in the circumferential distributed actuator, the membrane force in the circumferential direction is the dominant force. The effects of cone angle, piezoelectric thickness, and piezoelectric layer segmentation on modal forces of each distributed actuator are also studied. In circumferential distributed actuator, modal forces increase as the cone angle increases. This phenomenon in the longitudinal and diagonal distributed actuator is almost reversed. The piezoelectric layer segmentation effect on the modal forces distribution is also evaluated, and it showed that this phenomenon has a critical effect on the modal forces distribution.

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9

Tang, Jian-Ming, and D. J. Thouless. "Longitudinal force on a moving potential." Physical Review B 58, no. 21 (December 1, 1998): 14179–82. http://dx.doi.org/10.1103/physrevb.58.14179.

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10

Ding, Li Fen, and Ji Long Xie. "Research on the Effect of Traction Tonnage on Train Longitudinal Impact." Key Engineering Materials 450 (November 2010): 466–69. http://dx.doi.org/10.4028/www.scientific.net/kem.450.466.

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The traction tonnage has important effect on train longitudinal impact. An integrated model of train longitudinal dynamics was established based on simulation and test results. The effect of the traction tonnage on train longitudinal dynamics was investigated through modeling different types of heavy-haul trains. The model was validated by using measured longitudinal force time histories from on-track tests. Case study shows that the traction tonnage has significant influence on train longitudinal impact; Train longitudinal force increases with traction tonnage. The relationships between the maximum coupler forces (including tensile and compressive forces) and traction tonnage were obtained with the least square method for cases of train under emergency baking and release condition. The established train longitudinal dynamics model provides a platform for car body and coupler structure optimization and train control.

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Karhu, Eric, Mark Gooyers, and Jeffrey L. Hutter. "Quantitative Friction-Force Measurements by Longitudinal Atomic Force Microscope Imaging." Langmuir 25, no. 11 (June 2, 2009): 6203–13. http://dx.doi.org/10.1021/la900005z.

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12

Arvidsson, Per M., Johannes Töger, Gianni Pedrizzetti, Einar Heiberg, Rasmus Borgquist, Marcus Carlsson, and Håkan Arheden. "Hemodynamic forces using four-dimensional flow MRI: an independent biomarker of cardiac function in heart failure with left ventricular dyssynchrony?" American Journal of Physiology-Heart and Circulatory Physiology 315, no. 6 (December 1, 2018): H1627—H1639. http://dx.doi.org/10.1152/ajpheart.00112.2018.

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Patients with heart failure with left ventricular (LV) dyssynchrony often do not respond to cardiac resynchronization therapy (CRT), indicating that the pathophysiology is insufficiently understood. Intracardiac hemodynamic forces computed from four-dimensional (4-D) flow MRI have been proposed as a new measure of cardiac function. We therefore aimed to investigate how hemodynamic forces are altered in LV dyssynchrony. Thirty-one patients with heart failure and LV dyssynchrony and 39 control subjects underwent cardiac MRI with the acquisition of 4-D flow. Hemodynamic forces were computed using Navier-Stokes equations and integrated over the manually delineated LV volume. The ratio between transverse (lateral-septal and inferior-anterior) and longitudinal (apical-basal) forces was calculated for systole and diastole separately and compared with QRS duration, aortic valve opening delay, global longitudinal strain, and ejection fraction (EF). Patients exhibited hemodynamic force patterns that were significantly altered compared with control subjects, including loss of longitudinal forces in diastole (force ratio, control subjects vs. patients: 0.32 vs. 0.90, P < 0.0001) and increased transverse force magnitudes. The systolic force ratio was correlated with global longitudinal strain and EF ( P < 0.01). The diastolic force ratio separated patients from control subjects (area under the curve: 0.98, P < 0.0001) but was not correlated to other dyssynchrony measures ( P > 0.05 for all). Hemodynamic forces by 4-D flow represent a new approach to the quantification of LV dyssynchrony. Diastolic force patterns separate healthy from diseased ventricles. Different force patterns in patients indicate the possible use of force analysis for risk stratification and CRT implantation guidance. NEW & NOTEWORTHY In this report, we demonstrate that patients with heart failure with left ventricular dyssynchrony exhibit significantly altered hemodynamic forces compared with normal. Force patterns in patients mechanistically reflect left ventricular dysfunction on the organ level, largely independent of traditional dyssynchrony measures. Force analysis may help clinical decision making and could potentially be used to improve therapy outcomes.

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Ruzmetov, Yadgor, Oksana Molchanova, and Jamol Shihnazarov. "Calculation of solid-state cargo fastener under the influence of longitudinal forces." E3S Web of Conferences 157 (2020): 01016. http://dx.doi.org/10.1051/e3sconf/202015701016.

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Cargo securing on a railway platform, elastic and retention fasteners, longitudinal transport force of inertia, forces in elastic fastenings. Purpose: The paper presents the calculation of the longitudinal transport force of inertia; determines the longitudinal force perceived by the elastic elements of the cargo securing; determines the reactions of retention bars depending on the number of bars and fasteners (nail); calculates the sum of all holding forces; calculates the forces in the elastic fasteners when exposed to longitudinal forces. Research methods: To determine the forces in the cargo securing devices, existing calculation methods are used. Moreover, the formulas of these techniques are presented in a form convenient for calculation. Main results: The paper proves that according to the existing method, the force in all elastic cargo fasteners under the influence of longitudinal forces has the same value, regardless of the different arrangement of the geometric parameters of the fasteners in space. The forces in them are more than 1.6 times higher than the permissible values. The calculations of forces in the elastic fasteners, which are performed by the specified method, are given. The results of the comparative analysis showed that the forces in all wire fasteners, in contrast to the existing calculation method, have different values. However, the strength of the second pair of wire fasteners of both one and the other direction is not ensured - the force in them more than two times exceeds the permissible value (61/24.8≈2.5), which will result in their destruction during the cargo transportation. Conclusions and their significance for the industry: Existing calculation methods do not provide guarantee strength of cargo fasteners. In the future, to calculate the fastening of cargo by shippers in the railway industry, a new calculation procedure should be applied for the allocation and fastening of cargo on the car.

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Liu, L. Q., Y. P. Shi, J. Y. Zhu, W. D. Su, S. F. Zou, and J. Z. Wu. "Longitudinal–transverse aerodynamic force in viscous compressible complex flow." Journal of Fluid Mechanics 756 (September 1, 2014): 226–51. http://dx.doi.org/10.1017/jfm.2014.403.

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AbstractWe report our systematic development of a general and exact theory for diagnosis of total force and moment exerted on a generic body moving and deforming in a calorically perfect gas. The total force and moment consist of a longitudinal part (L-force) due to compressibility and irreversible thermodynamics, and a transverse part (T-force) due to shearing. The latter exists in incompressible flow but is now modulated by the former. The theory represents a full extension of a unified incompressible diagnosis theory of the same type developed by J. Z. Wu and coworkers to compressible flow, with Mach number ranging from low-subsonic to moderate-supersonic flows. Combined with computational fluid dynamics (CFD) simulation, the theory permits quantitative identification of various complex flow structures and processes responsible for the forces, and thereby enables rational optimal configuration design and flow control. The theory is confirmed by a numerical simulation of circular-cylinder flow in the range of free-stream Mach number $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}M_{\infty }$ between 0.2 and 2.0. The L-drag and T-drag of the cylinder vary with $M_{\infty }$ in different ways, the underlying physical mechanisms of which are analysed. Moreover, each L-force and T-force integrand contains a universal factor of local Mach number $M$. Our preliminary tests suggest that the possibility of finding new similarity rules for each force constituent could be quite promising.

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Pestrikov, D. V. "Longitudinal cooling force due to magnetized electrons." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 554, no. 1-3 (December 2005): 13–19. http://dx.doi.org/10.1016/j.nima.2005.07.054.

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Gadzhialiev, M. M., and Z. Sh Pirmagomedov. "Quantum oscillations of the longitudinal magnetothermoelectromotive force." Russian Physics Journal 49, no. 10 (October 2006): 1151–52. http://dx.doi.org/10.1007/s11182-006-0237-z.

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Gong, Xiao Ping, and Hong Xiao. "Mechanical Characteristics Analysis of Type ∏ Terminal Restricted Configuration Transition Section for CRTSⅡ Slab Track." Applied Mechanics and Materials 90-93 (September 2011): 108–12. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.108.

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With full-bridge longitudinal-connected foundation plates,CRTSⅡslab track sets type ∏ terminal restricted configuration anchorage structure in the bedroad-bridge transition section,in order to transmit forces such as temperature force and braking force from foundation plate to subgrade. In connection with the deficiency of exsiting researches, through the established finite element analysis model on Type ∏ terminal restricted configuration transition section,its mechanical characteristics under the most unfavorable longitudinal load by changing the structural parameters of transition section are analyzed, focusing on the criterion that the range of maximum of longitudinal displacement is 3mm.Analysis results show that when the longitudinal force is being transmitted to the anchorage structure, the maximum stress and longitudinal displacement of main terminal restricted configuration are far less than the limit and this process has little influence on track geometrical regularity .The laying of sliding layer can ameliorate structural force and deformation. However, changing its friction coefficient has no effect. Moreover, as the soil is under elastic deformation stage, its elastic modulus presents significant effects on mechanical properties of transmit section while its internal friction angle and cohesion have no influence.

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Yang, Lin Jia, and Yi Han Tao. "Calculation of Regular Longitudinal Wave Force in MMG Model Based on CFD." Applied Mechanics and Materials 423-426 (September 2013): 1727–31. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1727.

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Wave force is one of the most important environmental disturbing forces in ship motion mathematical model. Calculating the wave force in ship mathematical model is of a great importance about prediction of ships maneuverability. In order to calculate the longitudinal wave force in MMG ship motion mathematical model, the CFD method was used in this work to build numerical wave flume. The 3D model of M/V YUKUN and hexahedral mesh of the domain of the flow field were made. Software Fluent was used to simulate the motion of YUKUN in regular longitudinal waves, and the wave force acting on YUKUN was obtained. Finally, regression formula was built based on the simulation results.

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Fogarty, Matthew J., and Gary C. Sieck. "Tongue muscle contractile, fatigue, and fiber type properties in rats." Journal of Applied Physiology 131, no. 3 (September 1, 2021): 1043–55. http://dx.doi.org/10.1152/japplphysiol.00329.2021.

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For the individual tongue muscles, relatively little quantification of uniaxial force, fatigue, and fiber type-specific properties has been documented. Here, we assessed uniaxial-specific force generation, fatigability, and muscle fiber type-specific properties in the superior and inferior longitudinal muscles, the transversalis, and the genioglossus in Fischer 344 rats. The longitudinal muscles produced the greatest isometric tetanic-specific forces. The genioglossus was more fatigue resistant and comprised higher proportions of I and IIa fibers.

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Ilgamov, Marat A. "Buckling of an Oscillating Rod Under Longitudinal Impact." International Journal of Structural Stability and Dynamics 19, no. 03 (March 2019): 1971001. http://dx.doi.org/10.1142/s0219455419710019.

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The dynamics of a thin rod under the action of compressive force is considered. The compressive force increases abruptly and then remains constant. The compression of the rod is assumed to take place instantly throughout its length. The motion of the rod is studied, depending on the magnitude and time of action of the compressive force defined by the phase of the initial free oscillation of the rod. Only the initial stage of the process is investigated, for which the linear bending theory is valid. The friction forces are not taken into account. An essential relationship is shown to exist between the dynamics of the rod and the initial conditions determined by the phase of the bending oscillations at the instant of impact. Relatively weak impact leads to excitation of the bending oscillations. Rearrangement of harmonics develops with time under specified initial maximum deflection from a straight line and zero velocity. The fastest buckling takes place at some initial deflection with the velocity directed toward the increasing bend.

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Chen, Hong Kai, Hong Mei Tang, Ting Hu, Yi Hu, and Xiao Ying He. "Study on Numerical Simulation for Failure Process of Girder Bridge under Seismic Influence." Advanced Materials Research 530 (June 2012): 122–29. http://dx.doi.org/10.4028/www.scientific.net/amr.530.122.

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Based on the finite element analysis software Midas, it takes response spectrum analysis, and posts the failure mechanism and characteristics of Girder Bridge under intense earthquake. Through the seismic response spectrum displacement maps of Girder Bridge, it finds out that the abutment and foundation deformation is in evidence, especially the top of abutment foundation. Through the study of seismic internal force variation on girder and pier, it indicates that the longitudinal earthquake controls axial force, vertical shearing force and in-plane bending moment, transversal earthquake dominates transversal shearing force and out-planes bending moment. And it shows that the pier and mid-span section are seismic response sensitivity parts. The three parts, axial force, longitudinal shearing force and in-plane bending moment, becomes the controlling index of pier intensity. According to the seismic response spectrum displacement for pier and abutment, the transversal anti-seismic stiffness of pier is smaller than longitudinal one, longitudinal seismic force shows no effect on transversal displacement, and the transversal seismic force can augments longitudinal displacement. At the same condition, longitudinal seismic force changes the longitudinal distributing form of abutment and concaves it deeply, and the transversal seismic force can not change its shape, but augment its value.

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Lee, Hyeongcheol, and Masayoshi Tomizuka. "Coordinated Longitudinal and Lateral Motion Control of Vehicles for IVHS." Journal of Dynamic Systems, Measurement, and Control 123, no. 3 (March 24, 1998): 535–43. http://dx.doi.org/10.1115/1.1386395.

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This paper presents a systematic design of the combined control of vehicle longitudinal and lateral motions for the Intelligent Vehicle Highway Systems (IVHS). A fully coordinated control of the steering and the accelerating/braking actions is presented to maximize the ability of distributing the traction forces in a desired way. This control method covers a broad range of driving condition by removing several conventional simplification on vehicle dynamics, such as the linearized lateral traction force assumption, the bicycle model assumption, and the non-slip assumption. The nominal traction force concept is also introduced to handle the unknown traction forces. Robust Adaptive Control (RAC) by backstepping for MIMO nonlinear systems is utilized to control the unmatched nonlinear vehicle dynamics, in the presence of parametric uncertainties and uncertain nonlinearities.

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Zhang, Peng, Li Xin Cui, Le He, and Qun Sheng Xia. "Simulation Analysis of Tire Dynamic Model." Applied Mechanics and Materials 312 (February 2013): 167–71. http://dx.doi.org/10.4028/www.scientific.net/amm.312.167.

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The tire dynamics simulation was done for the different speeds on the dry and wet roads with Magic Formula tire model. The coefficients of Magic Formula tire model under different conditions were obtained by means of the tire test data based on the nonlinear least squares method. The Magic Formula has a good ability to fit the test data for the longitudinal, lateral force and align moment. The tire dynamics simulation results show that at 30mph the wet tire peak longitudinal and lateral forces are only slightly less than the dry peak forces. The wet tire peak longitudinal and lateral forces decreases as the tire speed increases. This shows that the speed has a larger impact on the tire force. The align moment is relatively small. So it can be ignored in the vehicle dynamics analysis.

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Nakano, Takato, Junji Sugiyama, and Misato Norimoto. "Contractive Force and Transformation of Microfibril with Aqueous Sodium Hydroxide Solution for Wood." Holzforschung 54, no. 3 (April 13, 2000): 315–20. http://dx.doi.org/10.1515/hf.2000.053.

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Summary The mechanism of longitudinal contraction of Yezo spruce (Picea jezoensis Carr.) during treatment with aqueous NaOH solution is discussed. The contraction of wood samples increased with an increase in the concentration of NaOH solution and in heating temperature. Measurements of the stress relaxation and the twist angle during the alkali treatment showed that the alkali treatment caused the contractive and twist forces of a tracheid cell wall in longitudinal and tangential directions, depending on the components of contractive force. The temperature dependence of the contraction and the thermodynamics led to the conclusion that the longitudinal contraction of samples is due to that of microfibrils via an entropy-elastic force.

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Krishna, Visakh V., Daniel Jobstfinke, Stefano Melzi, and Mats Berg. "An integrated numerical framework to investigate the running safety of overlong freight trains." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 235, no. 1 (February 18, 2020): 47–60. http://dx.doi.org/10.1177/0954409720905203.

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Long freight trains up to 1500 m in length are currently not in regular operation in Europe. One of the important reasons for the same is high inter-wagon forces generated during the operation, especially when pneumatic (P-type) brake systems are used. For long trains with multiple locomotives at different positions along the train, radio communication with necessary fail-safe mechanisms can be used to apply the brakes. Long freight train operation on a given line is subjected to various attributes such as braking/traction scenarios, loading patterns, wagon geometries, brake-block materials, buffer types, track design geometries, etc., which are referred to as heterogeneities. The complex longitudinal train dynamics arising in the train due to various heterogeneities play a major role in determining its running safety. In this context, the maximum in-train force refers to the maximum force developed between any two wagons along the train during operation. The tolerable longitudinal compressive force is the maximum compressive force that can be exerted on a wagon without resulting in its derailment. Here, the authors adopt a bottom-up approach to model pneumatic braking systems and inter-wagon interactions in multibody simulation environments to study the complex longitudinal train dynamics behavior and estimate maximum in-train forces and tolerable longitudinal compressive forces, subjected to various heterogeneities. These two force quantities intend to facilitate a given freight train operation by providing guidelines regarding the critical heterogeneities, that currently limit its safe operation. In doing so, the authors propose the notion to have an operation-based approval for long freight trains using the simulations-based tool.

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Tаmilа, V. A., and M. L. Nesterovich. "Bending technology of high strength steel sheets and tools for its realization." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 1 (April 7, 2020): 50–55. http://dx.doi.org/10.21122/1683-6065-2020-1-50-55.

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The article proposes and theoretically justifies a method for bending high-strength steels with compression. The technology allows to get parts from high-strength steels without cracks along the bending line. In the case of bending according to the proposed method, the deformation is carried out by the combined action of longitudinal and lateral forces. Equitations are derived showing the stress distribution over the cross section in the deformation zone. The article proposes and theoretically justifies a method for bending high-strength steels with compression. The technology allows you to get parts from high-strength steels without cracks along the bending line. In the case of bending according to the proposed method, the deformation is carried out by the action of longitudinal and transverse forces. Equitations were derived for finding the longitudinal compressive force at which the neutral layer in the workpiece moves to the outer surface based on the equations of stress distribution. Equitations are derived for finding the moment created by the longitudinal compressive force, as well as the moment formed by the action of compressive stresses, which made it possible to derive the equation for the external bending moment during bending with compression. Equitation is derived for finding the shoulder of the force action creating an external bending moment. Equitation is derived for finding the force of the punch for bending with compression.

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Chen, Te, Long Chen, Xing Xu, Yingfeng Cai, Haobin Jiang, and Xiaoqiang Sun. "Reliable Sideslip Angle Estimation of Four-Wheel Independent Drive Electric Vehicle by Information Iteration and Fusion." Mathematical Problems in Engineering 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/9075372.

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Accurate estimation of longitudinal force and sideslip angle is significant to stability control of four-wheel independent driven electric vehicle. The observer design problem for the longitudinal force and sideslip angle estimation is investigated in this work. The electric driving wheel model is introduced into the longitudinal force estimation, considering the longitudinal force is the unknown input of the system, the proportional integral observer is applied to restructure the differential equation of longitudinal force, and the extended Kalman filter is utilized to estimate the unbiased longitudinal force. Using the estimated longitudinal force, considering the unknown disturbances and uncertainties of vehicle model, the robust sideslip angle estimator is proposed based on vehicle dynamics model. Moreover, the recursive least squares algorithm with forgetting factor is applied to vehicle state estimation based on the vehicle kinematics model. In order to integrate the advantages of the dynamics-model-based observer and kinematics-model-based observer and improve adaptability of observer system in complex working conditions, a vehicle sideslip angle fusion estimation strategy is proposed. The simulations and experiments are implemented and the performance of proposed estimation method is validated.

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Vargiu, Romina, Anna Perinu, Antonello De Lisa, Frank Tintrup, Francesco Manca, and Rino Mancinelli. "Origin of Motion in the Human Ureter: Mechanics, Energetics and Kinetics of the Myosin Molecular Motors." Urologia Journal 79, no. 2 (April 2012): 123–29. http://dx.doi.org/10.5301/ru.2012.9110.

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Background Ureteral peristalsis is the result of coordinated mechanical motor performance of longitudinal and circular smooth muscle layer of the ureter wall. The main aim of this study was to characterize in smooth muscle of proximal segments of human ureter, the mechanical properties at level of muscle tissue and at level of myosin molecular motors. Methods Ureteral samples were collected from 15 patients, who underwent nephrectomy for renal cancer. Smooth muscle strips longitudinally and circularly oriented from proximal segments of human ureter were used for the in vitro experiments. Mechanical indices including the maximum unloaded shortening velocity (Vmax), and the maximum isometric tension (P0) normalized per cross-sectional area, were determined in vitro determined in electrically evoked contractions of longitudinal and circular smooth muscle strips. Myosin cross-bridge (CB) number per mm2 (Ψ) the elementary force per single CB (Ψ) and kinetic parameters were calculated in muscle strips, using Huxley's equations adapted to nonsarcomeric muscles. Results Longitudinal smooth muscle strips exhibited a significantly (p<0.05) faster Vmax (63%) and a higher P0 (40%), if compared to circular strips. Moreover, longitudinal muscle strips showed a significantly higher unitary force (Ψ) per CB. However, no significant differences were observed in CB number, the attachment (f1) and the detachment (g2) rate constants between longitudinal and circular muscle strips. Conclusions The main result obtained in the present work documents that the mechanical, energetic and unitary forces per CB of longitudinal layer of proximal ureter are better compared to the circular one; these preliminary findings suggested, unlike intestinal smooth muscle, a major role of longitudinal smooth muscle layer in the ureter peristalsis.

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Bednarek, Włodzimierz. "Longitudinal displacements of railway jointless track due to local temperature difference on its length." Transportation Overview - Przeglad Komunikacyjny 2020, no. 2 (February 1, 2020): 11–27. http://dx.doi.org/10.35117/a_eng_20_02_02.

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In the paper is shown an analysis of a CWR track’s longitudinal displacements due to a local temperature difference on its length. The thermical forces on the railway track length arise due to a local temperature difference of rail, causing the local, zonal the longitudinal displacements of rail cross-sections. Axial displacements of track induce in succession a longitudinal reaction of roadbed in such a degree on which a arising displacements allow. Additionally a arising during track operating a variable longitudinal resistance on track’s length (generated among other things by different state of ballast compaction, different pressure force of rail foot to divider), periodical acting force from vehicles, different value of adhesion wheels with rails and also different stage of rail heating, cause a disturbance section of equilibrium state of CWR track. In certain cases it assumes a shape of rails micro displacements, which can take a form e.g. creep displacements leading to value changes of longitudinal forces on this segment length with arising displacements. In paper analytical form of considered problem is given and computational examples, diagrams and tables reflecting influence of analyzed parameters on obtained a CWR track’s longitudinal displacements due to local temperature difference on its length is inserted Keywords: CWR track; Longitudinal displacement; Local temperature difference

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Xie, Kaize, Weigang Zhao, Xiaopei Cai, Ping Wang, and Jia Zhao. "Interaction between Track and Long-Span Cable-Stayed Bridge: Recommendations for Calculation." Mathematical Problems in Engineering 2020 (May 11, 2020): 1–14. http://dx.doi.org/10.1155/2020/5463415.

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Geometric nonlinearity (GN) and initial internal forces (IIFs) are the basic characteristics of cable-stayed bridges, but now there is no effective method for analyzing the effect of them on bridge-track interaction of continuous welded rail (CWR) on cable-stayed bridge. A method for reconstructing the displacement-force curve of ballast longitudinal resistance was put forward according to the deformation of cable-stayed bridges under the completed bridge state. A feasibility study on the method was conducted via two aspects of the force and deformation of CWR on a 5 × 40 m single-line simple-supported beam bridge with initial deformation. With the multi-element modeling method and the updated Lagrangian formulation method, a rail-beam-cable-tower 3D calculation model considering the GN and IIFs of cable-stayed bridge was established. Taking a (140 + 462 + 1092 + 462 + 140 m) twin-tower cable-stayed bridge as an example, the impacts of GN and IIFs on bridge-track interaction were comparatively analyzed. The results show that the method put forward to reconstruct ballast longitudinal resistance can prevent the impact of initial deformation of bridge and makes it possible to consider the effect of IIFs of cable-stayed bridge on bridge-track interaction. The GN and IIFs play important roles in the calculation of rail longitudinal force due to vertical bending of bridge deck under train load and the variance of cable force due to negative temperature changes in bridge decks and rails with rail breaking, and the two factors can reduce rail longitudinal force and variance of cable force by 11.8% and 14.6%, respectively. The cable-stayed bridge can be simplified as a continuous beam bridge with different constraints at different locations, when rail longitudinal force due to positive temperature changes in bridge deck and train braking is calculated.

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Kuntanapreeda, Suwat. "Estimation of Longitudinal Tire Force Using Nonlinearity Observer." Open Journal of Applied Sciences 03, no. 02 (2013): 41–46. http://dx.doi.org/10.4236/ojapps.2013.32b008.

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Milenković-Babić, Miodrag. "Propeller thrust force contribution to airplane longitudinal stability." Aircraft Engineering and Aerospace Technology 90, no. 9 (November 14, 2018): 1474–78. http://dx.doi.org/10.1108/aeat-04-2017-0104.

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Purpose This paper aims to present the new information about propeller thrust force contribution to airplane longitudinal stability analysis. Design/methodology/approach The method presented in this paper is empirical, shows how propeller thrust force derivative can be obtained and gives some additional information about misinterpretation of the propeller thrust effects that are present in the current literature. Findings New information about propeller thrust force contribution to airplane longitudinal stability analysis has been presented. This information should enable more precise insight in aircraft stability analysis and better understanding of the physical process that occurs during maneuver flight. Practical implications The information presented in this paper is new and specific to the propeller aircraft configuration. The methods used here are standard procedure to evaluating propeller thrust force derivative. Originality/value The information in this paper presents theoretical results. The method for calculating thrust force contribution to the airplane longitudinal stability is given depending on the propeller type and should enable good engineering results.

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33

Klomp, M. "Longitudinal force distribution using quadratically constrained linear programming." Vehicle System Dynamics 49, no. 12 (December 2011): 1823–36. http://dx.doi.org/10.1080/00423114.2010.545131.

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SAKAMOTO, Yuichiro, and Michihiro YAMASHITA. "Longitudinal vibration analysis caused by tractive force variation." Proceedings of the Symposium on the Motion and Vibration Control 2017.15 (2017): C16. http://dx.doi.org/10.1299/jsmemovic.2017.15.c16.

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Zhao, Jin You, Xun Guo, Wan Cheng Liu, and Hong Liang Zuo. "Design Method of Longitudinal Bracing Force Based on Monte Carlo Simulation." Advanced Materials Research 255-260 (May 2011): 1944–48. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1944.

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The bracing force of top horizontal braces supporting a row of columns under the only vertical load has been investigated in this paper. A large number of one-story longitudinal column-bracing systems were modeled and analyzed by second-order analysis using finite element method, in which the random combination of the initial imperfections between columns and braces was well considered by Monte Carlo method. According to the analysis results, three kinds of instability modes of one-story column-bracing system have been found, triple-normal probability density function of the top horizontal bracing forces is established based on probability statistics, and the design bracing forces are also obtained. A check method based on the vertical load analysis is supplied for the top horizontal bracing forces which are usually designed by the longitudinal horizontal load.

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Vaishnav, Ramesh N., Jafar Vossoughi, Dali J. Patel, LaVal N. Cothran, Bernell R. Coleman, and Eleanor L. Ison-Franklin. "Effect of Hypertension on Elasticity and Geometry of Aortic Tissue From Dogs." Journal of Biomechanical Engineering 112, no. 1 (February 1, 1990): 70–74. http://dx.doi.org/10.1115/1.2891128.

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Inflation-extension experiments were carried out on segments of the descending thoracic aortas from 4 normotensive and 4 hypertensive dogs rendered hypertensive using either unilateral or bilateral renal artery constriction. Intravascular pressures up to 200 mm Hg and axial forces up to 200 g were used. The external diameter of the segment and the distance between two longitudinally spaced gage marks were recorded photographically at each pressure-force level combination. Dimensions in the undeformed configuration were measured at the end of the inflation-extension experiment. Data were analyzed for changes in geometry and force-deformation response. Results indicate that: 1. Under sustained hypertension the wall thickness in the undeformed configuration increases with a concurrent reduction in the in-situ longitudinal extension ratio. 2. This dual tissue response accomplishes substantial reductions in the circumferential and longitudinal stresses from the levels that would be reached at equivlaent pressures in the absence of these geometric changes. 3. At comparable intravascular pressures the extensibility in the circumferential direction is slightly greater for the hypertensive aortas as compared to normals. However, the stress-extension ratio relationship in the circumferential direction is similar in the two groups. 4. The stress-extension ratio relationship in the longitudinal direction indicates that the hypertensive aorta is stiffer than its normotensive counterpart.

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Sintov, Avishai, Or Tslil, and Shahar Frenkel. "Longitudinal Regrasping of Elongated Objects." Robotica 38, no. 4 (July 31, 2019): 639–51. http://dx.doi.org/10.1017/s0263574719000912.

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SUMMARYRegrasping is a manipulation to alternate between grasp configurations of an object to perform different tasks. We address a regrasping problem termed longitude regrasping to reposition a gripper along an elongated object. We propose an algorithm using the dynamics of the arm and a non-dexterous gripper to perform the manipulation. Energy control is used to toss the object up and catch it under the goal position. Clipped Linear Quadratic Regulator control approach is then applied to the gripper jaws to control the friction force on the object and to let it slide to the final goal position. The object sliding within the gripper is modeled as a semi-active linear joint where only dissipative forces can be applied to it. A set of experiments validated the feasibility of the method.

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Chen, C., and R. Kovacevic. "Thermomechanical modelling and force analysis of friction stir welding by the finite element method." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 218, no. 5 (May 1, 2004): 509–19. http://dx.doi.org/10.1243/095440604323052292.

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Friction stir welding (FSW) is a solid-state jointing technology, in which the butted plates are heated, plasticized and jointed locally by the plunged probe and shoulder moving along the joint line. The residual stresses due to the thermomechanical performance of the material and the constraint of the welded plates by the fixture are one of main concerns for this process. A prediction of the clamping force applied on the plates during FSW is expected to be helpful in controlling the residual stresses and weld quality. Furthermore, the prediction of the force history in FSW will be beneficial to understand the mechanics of the process and to provide valid models for controlling the process, especially in the case of robotic FSW. In this paper, a three-dimensional model based on a finite element method is proposed to study the thermal history and stress distribution in the weld and, subsequently, to compute mechanical forces in the longitudinal, lateral and vertical directions. The proposed model includes a coupled thermomechanical modelling. The parametric investigation of the effects of the tool rotational and longitudinal speed on the longitudinal, lateral and vertical forces is also conducted in order to compute the appropriate clamping force applied on the plates. Measurements by the load cells in the longitudinal, lateral and vertical directions are presented and reveal a reasonable agreement between the experimental results and the numerical calculations.

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Miller, A. D., J. Barbosa, and R. Latorre. "Analysis of Tug-Barge Connection Force Measurements." Marine Technology and SNAME News 38, no. 02 (April 1, 2001): 130–37. http://dx.doi.org/10.5957/mt1.2001.38.2.130.

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This paper summarizes the analysis of four integrated tug-barge (ITB) model tests in calm water and waves. The results show the relationship of the tug-barge connection forces to wavelength and heading, and indicate that the maximum longitudinal, transverse, and vertical connection forces occur at wave encounter angles of 0, 45, 225, and 0 deg, respectively. Additionally, the results of a simplified linear analysis are used to evaluate the possibility of obtaining connection force predictions based on force vector analysis and the relationship of connection force to block coefficient. Photo of ITB-A tug model in barge notch. (Courtesy of the estate of Emilio Garcia)

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Ning, Hao, Xiao Yin Lv, and Yi Jun Wang. "Research on Longitudinal Seismic Calculation Theory of Single-Story Factory Building." Applied Mechanics and Materials 166-169 (May 2012): 2471–77. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2471.

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Regarding the distribution modes of longitudinal horizontal seismic forces of single-story factory building with no purlin concrete roof, there are conflicts between Sections 9.8.1 and 5.2.6 in the Seismic Design of Buildings GB50011-2010[1]. We suggested distributing the longitudinal seismic forces according to the proportion of the gravity loads on the subordinate areas of the lateral force components. We recommended replacing clause 1 of section 9.1.8 with “Don’t consider the effective stiffness of the enclosure walls or the partition walls”. Then for the example in Single-story Factory building Design Examples, we calculated the longitudinal seismic forces with two methods, and proved the our recommended method was correct.

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41

Podder, Debarata, Amith Gadagi, Nisith Ranjan Mandal, and Sreekanta Das. "In Sight of a Fillet Joint Based on Welding Force Method." Journal of Ship Production and Design 32, no. 04 (November 1, 2016): 206–15. http://dx.doi.org/10.5957/jspd.2016.32.4.206.

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Analysis of fillet-welded T-sections was carried out using the commercial finite element software ANSYS® for SM400A shipbuilding steel. To avoid the time consuming experimental technique, this model was validated with the existing experimental and numerical results. The vertical deflection, transverse shrinkage, and longitudinal residual stress were considered to validate the present model. After validating the model, the longitudinal, transverse, and normal plastic strains were collected from flange, web, and weld bead portions throughout the thickness and were averaged. These plastic strains were converted into corresponding longitudinal, transverse, and normal welding forces and were applied in an elastic model to obtain the distortions. The average welding force method was found to be very efficient in determining the distortions of welded structures. It was found that the proper distortion pattern for single-sided fillet welding can be obtained by incorporating the additional shrinkage forces from the weld bead.

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42

Ma, Wei Hua, Shi Hui Luo, and Rong Rong Song. "A Study of Wheel Flange Partial Wear Problem of Heavy Haul Locomotive." Advanced Materials Research 204-210 (February 2011): 241–44. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.241.

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Aimed to wheel flange partial wear problem, the heavy haul train dynamic model was setup, and the coupler and buffer system was setup in detail. The dynamic performance of the train under the longitudinal coupler press force was simulated. The wheel/rail lateral force and wheel flange wear were analyses. Simulation results shown that the front locomotive will suffer a big longitudinal press force for the delay of the brake force transfer; this will lead the rotation of the coupler. The lateral force will apply to the car body at the position of coupler, which was caused by the longitudinal coupler force and the rotation angle of the coupler, then the wheel flange partial wear were induced as a result.

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43

Ching-Chuan Su. "Mechanisms for the longitudinal recoil force in railguns based on the Lorentz force law." IEEE Transactions on Magnetics 42, no. 9 (September 2006): 2193–95. http://dx.doi.org/10.1109/tmag.2006.878010.

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Zhang, Longwei, Hua Zhao, Eugene J. OBrien, Xudong Shao, and Chengjun Tan. "The influence of vehicle–tire contact force area on vehicle–bridge dynamic interaction." Canadian Journal of Civil Engineering 43, no. 8 (August 2016): 769–72. http://dx.doi.org/10.1139/cjce-2015-0465.

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This paper proposes an updated vehicle–tire contact force model to simulate vehicle–bridge interaction, considering the tire contact area and the thickness of the bridge wearing surface. In contrast to the traditional methods of using a single-point tire contact force with a moving average filter, the proposed model uses multiple-point contact forces to account for the tire contact area. Results show that both the longitudinal and transverse distribution of tire contact force have a significant effect.

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Wendt, I. R., and C. L. Gibbs. "Energy expenditure of longitudinal smooth muscle of rabbit urinary bladder." American Journal of Physiology-Cell Physiology 252, no. 1 (January 1, 1987): C88—C96. http://dx.doi.org/10.1152/ajpcell.1987.252.1.c88.

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Heat production, oxygen consumption, and lactate production of longitudinal smooth muscle from rabbit urinary bladder has been measured at 27 degrees C. In isometric contractions (initiated by 1-Hz electrical stimulation) ranging in duration from 2 to 300 s, total energy expenditure correlated linearly with the force-time integral. For any given force-time integral oxygen consumption could account for only approximately 60% of the total energy measured as heat production. A substantial contribution of aerobic lactate production to the total energy flux was observed. This lactate production was also linearly correlated with force-time integral and was of sufficient magnitude to account for the discrepancy between total energy expenditure determined as heat production and oxygen consumption. The suprabasal rate of energy expenditure during the maintenance of force was approximately 2.6 mW/g and remained constant throughout contractions of up to 5-min duration, suggesting that in this muscle there is no change in the energetic cost of force maintenance with increasing duration of contraction. The rate of energy expenditure during the initial period of force development was, however, about twofold greater than that during subsequent force maintenance, indicating that there is an extra energy cost associated with the activation of contraction and development of force above that required for force maintenance.

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Belyy, G. I. "Analytical-numerical method for calculating the stability of rod elements of lightweight steel structures." Вестник гражданских инженеров 17, no. 4 (2020): 39–46. http://dx.doi.org/10.23968/1999-5571-2020-17-4-39-46.

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The article proposes an analytical-numerical method for calculating the rod elements of lightweight steel structures for general stability, in which the reduced section is replaced with the unreduced one with compensating loading with a fictitious longitudinal force. The dependence of this force with uniaxial or biaxial eccentricities on the acting longitudinal force is established when they are combined acting on fictitious stresses in the center of the weakening gravity of the rod most stressed section. Therewith, the effect of displacements corresponding to the stability tasks (bending, bending-torsional or spatial ones) is taken into consideration. The analytical part of the stability problems` solution is constructed for the known parameters of the real abatement of the cross section, which is determined numerically under the combined action of all efforts using the EN 1993-1-3-2004 in combination with the "Cross-section" algorithm. To reduce the volume of calculations, there is proposed a reverse course of solving the stability problem in dimensionless parameters. The section reduction and the actual forces are numerically determined according to the limiting state of the rod in the most loaded initial section at given force parameters (relative eccentricities of the longitudinal force, taking into account displacements). Then, depending on the flexibility of the rod, the corresponding loading of the rod on its supports is specified by the reverse analytical solution.

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Du, Tao, Dong Yang, and Yao Ding. "Driving force for preventing smoke backlayering in downhill tunnel fires using forced longitudinal ventilation." Tunnelling and Underground Space Technology 79 (September 2018): 76–82. http://dx.doi.org/10.1016/j.tust.2018.05.005.

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Crăciun, C. I., and C. Cruceanu. "Longitudinal dynamic force distribution for different hysteretic buffer characteristics." IOP Conference Series: Materials Science and Engineering 444 (November 29, 2018): 042003. http://dx.doi.org/10.1088/1757-899x/444/4/042003.

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Chang, Chongyi, Gang Guo, Junbiao Wang, and Yingming Ma. "Study on longitudinal force simulation of heavy-haul train." Vehicle System Dynamics 55, no. 4 (December 28, 2016): 571–82. http://dx.doi.org/10.1080/00423114.2016.1269183.

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El Hadri, A., G. Beurier, J. C. Cadiou, N. K. M'Sirdi, and Y. Delanne. "Longitudinal Tire Force Estimation Based on Sliding Mode Observer." IFAC Proceedings Volumes 34, no. 1 (March 2001): 41–46. http://dx.doi.org/10.1016/s1474-6670(17)34375-6.

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Journal articles on the topic 'Longitudinal force'

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