Journal articles on the topic 'Force and moment'
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Shim, Jae Kun, Brendan S. Lay, Vladimir M. Zatsiorsky, and Mark L. Latash. "Age-related changes in finger coordination in static prehension tasks." Journal of Applied Physiology 97, no. 1 (July 2004): 213–24. http://dx.doi.org/10.1152/japplphysiol.00045.2004.
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We studied age-related changes in the performance of maximal and accurate submaximal force and moment production tasks. Elderly and young subjects pressed on six dimensional force sensors affixed to a handle with a T-shaped attachment. The weight of the whole system was counterbalanced with another load. During tasks that required the production of maximal force or maximal moment by all of the digits, young subjects were stronger than elderly. A greater age-related deficit was seen in the maximal moment production tests. During maximal force production tests, elderly subjects showed larger relative involvement of the index and middle fingers; they moved the point of thumb force application upward (toward the index and middle fingers), whereas the young subjects rolled the thumb downward. During accurate force/moment production trials, elderly persons were less accurate in the production of both total moment and total force. They produced higher antagonistic moments, i.e., moment by fingers that acted against the required direction of the total moment. Both young and elderly subjects showed negative covariation of finger forces across repetitions of a ramp force production task. In accurate moment production tasks, both groups showed negative covariation of two components of the total moment: those produced by the normal forces and those produced by the tangential forces. However, elderly persons showed lower values of the indexes of both finger force covariation and moment covariation. We conclude that age is associated with an impaired ability to produce both high moments and accurate time profiles of moments. This impairment goes beyond the well-documented deficits in finger and hand force production by elderly persons. It involves worse coordination of individual digit forces and of components of the total moment. Some atypical characteristics of finger forces may be viewed as adaptive to the increased variability in the force production with age.
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Hocevar, Richard A. "Moment/force ratios." American Journal of Orthodontics and Dentofacial Orthopedics 91, no. 4 (April 1987): 350. http://dx.doi.org/10.1016/0889-5406(87)90179-x.
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Lapatki, B. G., J. Bartholomeyczik, P. Ruther, I. E. Jonas, and O. Paul. "Smart Bracket for Multi-dimensional Force and Moment Measurement." Journal of Dental Research 86, no. 1 (January 2007): 73–78. http://dx.doi.org/10.1177/154405910708600112.
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Atraumatic, well-directed, and efficient tooth movement is interrelated with the therapeutic application of adequately dimensioned forces and moments in all three dimensions. The lack of appropriate monitoring tools inspired the development of an orthodontic bracket with an integrated microelectronic chip equipped with multiple piezoresistive stress sensors. Such a ‘smart bracket’ was constructed (scale of 2.5:1) and calibrated. To evaluate how accurately the integrated sensor system allowed for the quantitative determination of three-dimensional force-moment systems externally applied to the bracket, we exerted 396 different force-moment combinations with dimensions within usual therapeutic ranges (± 1.5 N and ± 15 Nmm). Comparison between the externally applied force-moment components and those reconstructed on the basis of the stress sensor signals revealed very good agreement, with standard deviations in the differences of 0.037 N and 0.985 Nmm, respectively. We conclude that our methodological approach is generally suitable for monitoring the relatively low forces and moments exerted on individual teeth with fixed orthodontic appliances.
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LEE, C. S., N. L. WONG, S. SRIGRAROM, and N. T. NGUYEN. "DEVELOPMENT OF 3-COMPONENT FORCE-MOMENT BALANCE FOR LOW SPEED WATER TUNNEL." Modern Physics Letters B 19, no. 28n29 (December 20, 2005): 1575–78. http://dx.doi.org/10.1142/s0217984905009948.
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An effort is made to develop a new 3-component force-moment balance, which is capable of measuring lift force, drag force and pitching moment of a model mounted in the water tunnel. The concept used in the balance design is the bending- beam principle. The forces acting on the spring element cause strains on its surface, which are measured by strain gauges. Since strain yielded by the axial force is usually very small, therefore it is not practical to measure axial force using strain gauge directly to sense the strain in axial direction. The main idea of the new balance design is to translate all desired forces (lift and drag) in such a way that they yield bending strain at selected strain-gauge station. This is done by using a bending balance geometry. Under this apparatus, the model wing is mounted at one of its end to the bending balance. The corresponding Lift, Drag forces and Pitching moment are translated into moments at the other end of the balance, and can be measured from sets of strain gauges in bending mode (twisting mode for pitching moment). Example readings are presented in this paper.
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Nurhadi, Nurhadi, Mochammad Nasir, Chandra Permana, and Endah Suwarni. "Design and Manufacture of 6 Axis Force and Moments Transducers for Seaplane Floaters Test in Towing Tank." EPI International Journal of Engineering 3, no. 1 (September 1, 2020): 84–89. http://dx.doi.org/10.25042/epi-ije.022020.12.
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To develop seaplanes as a means of inter-island transportation, it is necessary to have a simulation, testing, and analysis of force measurements that work so that the aircraft can be designed optimally in terms of function and safety.
To fulfill one type of test, the seaplane floater model is pulled in the Towing Tank to determine the hydrodynamic forces acting on the floater which include resistance (Fx), side force (Fy), lift force (Fz), and moments in all three axes. A method of measuring the force of 6 axis force and moment or 6 degrees of freedom (6 Degree of Freedom, 6 DOF) was built and designed by combining several single load cells so that these forces can be known optimally.
From the results of the 6 DOF transducer design, it is proven that it can be used well in measuring 6 forces and moments with force measurement errors ranging from 1.38%. The distance between the 6 DOF transducer capture point and the floater force capture point will affect the measured moment transformation.
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Yee, Albert G., and C. Daniel Mote. "Forces and Moments at the Knee and Boot Top: Models for an Alpine Skiing Population." Journal of Applied Biomechanics 13, no. 3 (August 1997): 373–84. http://dx.doi.org/10.1123/jab.13.3.373.
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The purpose of this study was to identify regression models to predict moments at the boot top and knee from the force components at the bindings for a sample of skiers. Six subjects skied a slalom course, first with their boots set to the least stiff setting and then with their boots set to the most stiff setting. Six load component dynamometers measured force and moment components at the toe and heel bindings. An electrogoniometer measured ankle flexion. Regression models were developed for the subject sample that predicted quasi-static moment components at the boot top and knee from measurements of ankle flexion and the quasi-static force components at the bindings. Large anterior bending moment was not necessarily accompanied by large ankle flexion, which emphasized that binding designs and standards for injury prevention must account for forces and moments at the sites of potential injury, rather than limiting consideration to boot stiffness or forces at the bindings.
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Almeida, Layene, Alexandre Ribeiro, Renato Parsekian Martins, Rodrigo Viecilli, and Lídia Parsekian Martins. "Nickel titanium T-loop wire dimensions for en masse retraction." Angle Orthodontist 86, no. 5 (January 11, 2016): 810–17. http://dx.doi.org/10.2319/070515-449.1.
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ABSTRACT Objective: To compare the force system produced by nickel-titanium T-loop springs made with wires of different dimensions. Material and Methods: Thirty compound T-loop springs were divided into three groups according to the dimensions of the nickel-titanium wire used for its design: 0.016” × 0.022”, 0.017” × 0.025”, and 0.018” × 0.025”. The loops were tested on the Orthodontic Force Tester machine at an interbracket distance of 23 mm and activated 9 mm. The force in the y-axis and the moment in the x-axis were registered while the calculated moment to force ratio was recorded at each .5 mm of deactivation. The data were analyzed by three analyses of variance of repeated measures to detect differences and interactions between deactivation and wire size on force, moment, and moment-force ratios (M/F). Results: All groups had significantly different forces (P < .001). The 0.016” × 0.022” wire produced 1.78N of force while the 0.017” × 0.025” and the 0.018” × 0.025” produced 2.81 N and 3.25 N, respectively. The 0.016” × 0.022” wire produced lower moments (11.6 Nmm) than the 0.017” × 0.025” and 0.018” × 0.025” wires, which produced similar moments (13.9 Nmm and 14.4Nmm, respectively). The M/F produced was different for all groups; 0.016” × 0.022” T-loops produced 6.7 mm while the 0.017” × 0.025” and 0.018” × 0.025” T-loops produced 5.0 mm and 4.5 mm, respectively. An interaction was detected for all variables between deactivation and groups. Conclusion: The larger wires tested produced higher forces with slight increase on the moments, but the M/F produced by the 0.016” × 0.022” wire was the highest found.
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OHUE, Toshikazu. "Universal Force-Moment Sensors." Journal of the Robotics Society of Japan 9, no. 7 (1991): 914–15. http://dx.doi.org/10.7210/jrsj.9.914.
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Nahoum, Henry I. "Moment-to-force ratio." American Journal of Orthodontics and Dentofacial Orthopedics 134, no. 2 (August 2008): 176–77. http://dx.doi.org/10.1016/j.ajodo.2008.06.010.
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Radt, H. S., and D. A. Glemming. "Normalization of Tire Force and Moment Data." Tire Science and Technology 21, no. 2 (April 1, 1993): 91–119. http://dx.doi.org/10.2346/1.2139525.
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Abstract Semi-empirical theories of tire mechanics are employed to determine appropriate means to normalize forces, moments, angles, and slip ratios. Force and moment measurements on a P195/70R 14 tire were normalized to show that data at different loads could then be superimposed, yielding close to one normalized curve. Included are lateral force, self-aligning torque, and overturning moment as a function of slip angle, inclination angle, slip ratio, and combinations. It is shown that, by proper normalization of the data, one need only determine one normalized force function that applies to combinations of slip angle, camber angle, and load or slip angle, slip ratio, and load. Normalized curves are compared for the effects of inflation pressure and surface water thickness. Potential benefits as well as limitations and deficiencies of the approach are presented.
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Ghadimi, Parviz, and Saeid Panahi. "Numerical investigation of hydrodynamic forces acting on the non-stepped and double-stepped planing hulls during yawed steady motion." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 233, no. 2 (January 19, 2018): 428–42. http://dx.doi.org/10.1177/1475090217751549.
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This article focuses on the steady motion of yawed planing hulls with emphasis on the effects of adding steps to the bottom of these vessels on the hydrodynamic forces and moments acting on the boat. To analyze the problem, the Ansys-CFX software is used and three different planing hulls are investigated in steady yawed condition. The main targeted results include hydrodynamic forces and moments acting on the boat at different yaw angles and beam Froude numbers which provide important insights regarding the effects of loading and adding step on these forces and moments. The numerically predicted sway forces are compared against experimental data, suggesting that the current numerical model predicts sway and surge forces with reasonable accuracy. Moreover, it is observed that surge force coefficient of the investigated prismatic planing hull with light loading condition does not change significantly when the hull is relocated in a yaw angle, while it is remarkably affected when the boat is heavy. Furthermore, it is observed that this prismatic planing hull has smaller rolling moment in a steady yawed motion, when it moves at larger beam Froude number. Meanwhile, the computed yawing moments of this hull indicate that an increase in speed does not change this moment notably, while an increase in its weight yields larger yawing moment. Comparison of the results of stepped and non-stepped planing hulls indicates that surge force coefficient of the stepped hull is larger, while its sway force and rolling moment are smaller. This is mainly caused by the shape of the interrupted wetted surface and larger number of maximum pressure area in the stepped planing hull. Finally, it is concluded that there is no significant difference between the yawing moment of the investigated stepped and non-stepped planing hulls.
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Shim, Jae Kun, Mark L. Latash, and Vladimir M. Zatsiorsky. "Prehension Synergies: Trial-to-Trial Variability and Principle of Superposition During Static Prehension in Three Dimensions." Journal of Neurophysiology 93, no. 6 (June 2005): 3649–58. http://dx.doi.org/10.1152/jn.01262.2004.
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We performed three-dimensional analysis of the conjoint changes of digit forces during prehension (prehension synergies) and tested applicability of the principle of superposition to three-dimensional tasks. Subjects performed 25 trials at statically holding a handle instrumented with six-component force/moment sensors under seven external torque conditions; –0.70, –0.47, –0.23, 0.00, 0.23, 0.47, and 0.70 Nm about a horizontal axis in the plane passing through the centers of all five digit force sensors (the grasp plane). The total weight of the system was always 10.24 N. The trial-to-trial variability of the forces produced by the thumb and the virtual finger (an imagined finger producing the same mechanical effects as all 4 finger forces and moments combined) increased in all three dimensions with the external torque magnitude. The sets of force and moment variables associated with the moment production about the vertical axis in the grasp plane and the axis orthogonal to the grasp plane consisted of two noncorrelated subsets each; one subset of variables was related to the control of grasping forces ( grasp control) and the other sassociated with the control of the orientation of the hand-held object ( torque control). The variables associated with the moment production about the horizontal axis in the grasp plane did not include the grip force (the normal thumb and virtual finger forces) and showed more complex noncorrelated subsets. We conclude that the principle of superposition is valid for the prehension in three dimensions. The observed high correlations among forces and moments associated with the control of object orientation could be explained by chain effects, the sequences of cause-effect relations necessitated by mechanical constraints.
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Caldas, Sergei Godeiro Fernandes Rabelo, Renato Parsekian Martins, Marcela Emílio de Araújo, Marília Regalado Galvão, Roberto Soares da Silva Júnior, and Lídia Parsekian Martins. "Stability of beta-titanium T-loop springs preactivated by gradual curvature." Dental Press Journal of Orthodontics 22, no. 6 (November 2017): 61–67. http://dx.doi.org/10.1590/2177-6709.22.6.061-067.oar.
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ABSTRACT Objective: Evaluate changes in the force system of T-Loop Springs (TLS) preactivated by curvature, due to stress relaxation. Methods: Ninety TLSs measuring 6 x 10 mm, produced out with 0.017 x 0.025-in TMA® wire and preactived by gradual curvature, were randomly distributed into nine groups according to time point of evaluation. Group 1 was tested immediately after spring preactivation and stress relief, by trial activation. The other eight groups were tested after 24, 48 and 72 hours, 1, 2, 4, 8 and 12 weeks, respectively. Using a moment transducer coupled to a digital extensometer indicator adapted to a universal testing machine, the amount of horizontal force, moment and moment-to-force ratios were recorded at every 0.5 mm of deactivation from 5 mm of the initial activation, in an interbracket distance of 23 mm. Results: The horizontal forces decreased gradually among the groups (p< 0.001) and the moments showed a significant and slow decrease over time among the groups (p< 0.001). All groups produced similar M/F ratios (p= 0.532), with no influence of time. Conclusions: The TLSs preactivated by curvature suffered a gradual deformation over time, which affected the force system, specifically the moments, which affected the horizontal forces produced.
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Full, R., and A. Ahn. "Static forces and moments generated in the insect leg: comparison of a three-dimensional musculo-skeletal computer model with experimental measurements." Journal of Experimental Biology 198, no. 6 (June 1, 1995): 1285–98. http://dx.doi.org/10.1242/jeb.198.6.1285.
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As a first step towards the integration of information on neural control, biomechanics and isolated muscle function, we constructed a three-dimensional musculo-skeletal model of the hind leg of the death-head cockroach Blaberus discoidalis. We tested the model by measuring the maximum force generated in vivo by the hind leg of the cockroach, the coxa­femur joint angle and the position of this leg during a behavior, wedging, that was likely to require maximum torque or moment production. The product of the maximum force of the leg and its moment arm yielded a measured coxa­femur joint moment for wedging behavior. The maximum musculo-apodeme moment predicted by summing all extensor muscle moments in the model was adequate to explain the magnitude of the coxa­femur joint moment produced in vivo by the cockroach and occurred at the same joint angle measured during wedging. Active isometric muscle forces predicted from our model varied by 3.5-fold among muscles and by as much as 70 % with joint angle. Sums of active and passive forces varied by less than 3.5 % over the entire range of possible joint angles (0­125 °). Maximum musculo-apodeme moment arms varied nearly twofold among muscles. Moment arm lengths decreased to zero and switched to the opposite side of the center of rotation at joint angles within the normal range of motion. At large joint angles (>100 °), extensors acted as flexors. The effective mechanical advantage (musculo-apodeme moment arm/leg moment arm = 0.10) resulted in the six femoral extensor muscles of the model developing a summed force (1.4 N) equal to over 50 times the body weight. The model's three major force-producing extensor muscles attained 95 % of their maximum force, moment arm and moment at the joint angle used by the animal during wedging.
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Zhu, Dan, Qiang Wang, and Ming Lang Hu. "The Inertia Force of Insect-Like Flapping Wing Micro Air Vehicle." Advanced Materials Research 327 (September 2011): 186–92. http://dx.doi.org/10.4028/www.scientific.net/amr.327.186.
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We used the method of theoretical modeling and simulation to study how changes in wing kinematics influence the production of inertia forces and moments in flapping flight. We examined 153 separate sets of kinematic patterns that differed with respect to stroke amplitude, mid-stroke angle of attack, acceleration and deceleration duration of flip rotation and acceleration and deceleration duration of azimuthal rotation. For each pattern, we also calculated mean stroke- or quarter - averaged values of the inertia forces and force moments. The results of the analysis may be divided into three main point: (i) The insect wing’s chordwise inertia is much higher than its spanwise inertia--higher by an order of magnitude; (ii) The influence of inertia moment of azimuthal rotation is much higher than that of inertia moment of flip rotation, so the inertia moment of flip rotation can be ignored; (iii) Consider the flapping motion is approximate symmetrical if the stroke is symmetrical and the flapping motion is absolute symmetrical if the stroke and the flip is both symmetrical, then the inertia force can be ignored.
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Parsa, Behnoosh, Daniel J. O'Shea, Vladimir M. Zatsiorsky, and Mark L. Latash. "On the nature of unintentional action: a study of force/moment drifts during multifinger tasks." Journal of Neurophysiology 116, no. 2 (August 1, 2016): 698–708. http://dx.doi.org/10.1152/jn.00180.2016.
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We explored the origins of unintentional changes in performance during accurate force production in isometric conditions seen after turning visual feedback off. The idea of control with referent spatial coordinates suggests that these phenomena could result from drifts of the referent coordinate for the effector. Subjects performed accurate force/moment production tasks by pressing with the fingers of a hand on force sensors. Turning the visual feedback off resulted in slow drifts of both total force and total moment to lower magnitudes of these variables; these drifts were more pronounced in the right hand of the right-handed subjects. Drifts in individual finger forces could be in different direction; in particular, fingers that produced moments of force against the required total moment showed an increase in their forces. The force/moment drift was associated with a drop in the index of synergy stabilizing performance under visual feedback. The drifts in directions that changed performance (non-motor equivalent) and in directions that did not (motor equivalent) were of about the same magnitude. The results suggest that control with referent coordinates is associated with drifts of those referent coordinates toward the corresponding actual coordinates of the hand, a reflection of the natural tendency of physical systems to move toward a minimum of potential energy. The interaction between drifts of the hand referent coordinate and referent orientation leads to counterdirectional drifts in individual finger forces. The results also demonstrate that the sensory information used to create multifinger synergies is necessary for their presence over the task duration.
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Lim, Yeen, Andrew Quick, Michael Swain, and Peter Herbison. "Temperature Effects on the Forces, Moments and Moment to Force Ratio of Nickel-Titanium and TMA Symmetrical T-loops." Angle Orthodontist 78, no. 6 (November 1, 2008): 1035–42. http://dx.doi.org/10.2319/092707-460.1.
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Abstract Objective: To test the null hypothesis that temperature has no effect on the force, moment, and moment to force ratio (M:F) of nickel-titanium (NiTi) and titanium molybdenum alloy (TMA) T-loops. Materials and Methods: Twelve symmetrical T-loops were constructed from NiTi and TMA rectangular wires (N = 24). For each material, four specimens had 30° preactivation bent into the legs, four had 15°, and the remainder no preactivation. The specimens were mounted on a custom stand incorporating a force and a moment transducer housed in an insulated oven in which the temperature was varied from 10°C to 50°C in 10° increments (±0.5°C). The loops were opened in 1-mm increments to a maximum of 8 mm and allowed to return to the rest position. Forces and moments were recorded at each interval; from this, the M:F was calculated. Mixed-model statistical analysis was used to detect differences between mean results of material type, preactivation, and temperature. Results: Temperature significantly influenced the forces and moments (P < .000) produced by NiTi closing loops, with values increasing as the temperature increased. The M:F ratios of NiTi loops were less affected, with no significant changes with temperature for the 15° and 30° preactivation loops, although some change was noted for the non-preactivated loops. TMA wires showed significance for some force measurements, but were generally not influenced by temperature. Conclusion: The hypothesis is rejected. Temperature significantly affected the forces and moments produced by NiTi T-loops, though these changes generally do not affect the overall M:F ratio.
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Katona, Thomas R., Serkis C. Isikbay, and Jie Chen. "Effects of first- and second-order gable bends on the orthodontic load systems produced by T-loop archwires." Angle Orthodontist 84, no. 2 (August 29, 2013): 350–57. http://dx.doi.org/10.2319/031413-219.1.
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ABSTRACT Objective: To measure the effects of first- and second-order gable bends on the forces and moments produced by a commercially available closing T-loop archwire. Materials and Methods: A dentoform-simulated space closure case was mounted on an orthodontic force tester. Sixteen gable bend combinations were placed in the archwires, which were then activated using standard clinical procedures. At each activation, the three force components and three moment components on the maxillary left lateral incisor and canine were simultaneously measured. Results: The first- and second-order gable bends showed low load coupling effects when used independently, but the load systems became unpredictable when bends were combined. Gable bends affect the magnitudes and directions of the forces and moments that are applied to teeth. The resulting moment to force ratios are sensitive to the bends. Conclusion: Gable bends alter the orthodontic load systems; however, the three-dimensional interactions produce complex and unpredictable tradeoffs.
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Sahu, S. K., and A. K. Singh. "On Flexure-Shear Interaction in Fibre Model for the Analysis of RC Section." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 315–20. http://dx.doi.org/10.38208/acp.v1.515.
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This paper investigates the effects of flexure-shear interaction on the force-deformation response of RC section. The analysis is performed using an improved version of fibre section model to consider the interaction of shear force. The model uses a supplementary shear strain field, in addition to the ‘plane-section’ hypothesis, for section kinematics. The concrete is modelled using a bi-axial stress-strain model based on a rotating, smeared-crack model with equivalent uniaxial stress-strain relation in principal directions. The confining effect of stirrups is considered by using Mander model. The reinforcing bars are modelled using a uniaxial stress-strain relation. The use of bi-axial model allow the flexure-shear interaction to reflect at the material point. The fibre section model is used to analyse an RC section to study the moment-curvature and shear force-shear strain response for increasing levels of shear forces and bending moments. The results shows that the moment-curvature and shear force-shear strain diagrams are significantly influenced by the presence of large shear force and bending moment respectively.
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Wang, Haifei, and Junjie Gong. "Dynamic analysis of coupling misalignment and unbalance coupled faults." Journal of Low Frequency Noise, Vibration and Active Control 38, no. 2 (January 8, 2019): 363–76. http://dx.doi.org/10.1177/1461348418821582.
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Misalignment is a common fault occurring in the rotor system. However, the response characteristics have not been understood comprehensively, especially the relation between forces or torques and displacements, accelerations, or moments. First, misalignment modeling is investigated in this paper. Two coupled rotor system is modeled by six degrees of freedom. Misalignment effects are considered at coupling location using nodal force vectors and moment vectors. Second, Newmark- β method is used to solve the nonlinear equations. Acceleration, displacement, and force or moment response characteristics are discussed. Some results are obtained as follows: (1) 2× will appear in the parallel misalignment forces spectrum, and 0× will appear in the vertical force spectrum; 2×, 4×, 6× will appear in the angular misalignment moment spectrum. (2) In parallel misalignment simulation, it is found that multifrequency components are more obvious, static components are showed in vertical forces and displacements, 1× is dominated and 2× is weak in the displacement spectrum, and 2× is obvious in the force spectrum; acceleration is periodic impulse signal and 1× and 2× are dominated in its spectrum; vertical displacement is truncated and its values are positive, the orbit looks like an inverted triangle. (3) In angular misalignment simulation, it is found that multifrequency components of response are more obvious, 2× is obvious in the vertical displacement spectrum, and 2× is dominated in the moment spectrum; acceleration is periodic impulse signal, horizontal and vertical displacements are periodic, the orbit looks like a moon or an eight shape, and 2× is obvious in the moment spectrum.
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Caldwell, Graham E., James M. Hagberg, Steve D. McCole, and Li Li. "Lower Extremity Joint Moments during Uphill Cycling." Journal of Applied Biomechanics 15, no. 2 (May 1999): 166–81. http://dx.doi.org/10.1123/jab.15.2.166.
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Lower extremity joint moments were investigated in three cycling conditions: level seated, uphill seated and uphill standing. Based on a previous study (Caldwell, Li, McCole, & Hagberg, 1998), it was hypothesized that joint moments in the uphill standing condition would be altered in both magnitude and pattern. Eight national caliber cyclists were filmed while riding their own bicycles mounted to a computerized ergometer. Applied forces were measured with an instrumented pedal, and inverse dynamics were used to calculate joint moments. In the uphill seated condition the joint moments were similar in profile to the level seated but with a modest increase in magnitude. In the uphill standing condition the peak ankle plantarflexor moment was much larger and occurred later in the downstroke than in the seated conditions. The extensor knee moment that marked the first portion of the down-stroke for the seated trials was extended much further into the downstroke while standing, and the subsequent knee flexor moment period was of lower magnitude and shorter duration. These moment changes in the standing condition can be explained by a combination of more forward hip and knee positions, increased magnitude of pedal force, and an altered pedal force vector direction. The data support the notion of an altered contribution of both muscular and non-muscular sources to the applied pedal force. Muscle length estimates and muscle activity data from an earlier study (Li & Caldwell, 1996) support the unique roles of mono-articular muscles for energy generation and bi-articular muscles for balancing of adjacent joint moments in the control of pedal force vector direction.
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Yoshida, Yoshiki, Yoshinobu Tsujimoto, Goh Morimoto, Hiroki Nishida, and Shigeki Morii. "Effects of Seal Geometry on Dynamic Impeller Fluid Forces and Moments." Journal of Fluids Engineering 125, no. 5 (September 1, 2003): 786–95. http://dx.doi.org/10.1115/1.1598988.
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This paper reports an experimental investigation of the rotordynamic fluid force and moment on a centrifugal impeller with three types of wear-ring seals; i.e., a face seal and two types of toothed seals. The impeller is equipped with a vaneless diffuser. Rotordynamic fluid forces and moments on the impeller in whirling motion were measured directly by using four-axis force sensor. Unsteady pressures were measured at several locations in the diffuser. It was found that, (1) at low flow rate, the fluid force and fluid force moment become maximum at a certain whirling speed caused by a coupling between the whirl motion and vaneless diffuser rotating stall and (2) the seal geometry with axial seal affects the direction of the coupled fluid force relative to the direction of eccentricity through the change in the unsteady leakage flow due to the whirl.
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Hu, Wen, Shigang Wang, Chun Hu, Hongtao Liu, and Jinqiu Mo. "Vision-based force measurement using geometric moment invariants." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 10 (January 5, 2012): 2589–601. http://dx.doi.org/10.1177/0954406211432983.
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This article presents a new vision-based force measurement method to measure microassembly forces without directly computing the deformation. The shape descriptor of geometric moment invariants is used as a feature vector to describe the implicit relationship between an applied force and the deformation. Then, a standard library is established to map the corresponding relationship between the deformed cantilever under known forces and a set of feature vectors. Finally, a support vector machine compares the feature vector of deformed cantilever under an unknown force with those in the standard library, implements multi-class classification and predicts the unknown force. The vision-based force measurement method is validated for eight simulated microcantilevers of different sizes. Both regional and boundary moment invariants are used to constitute the feature vector. Simulated results show that the force measurement precision varies with length, width and height of cantilevers. If length increases and width and height decrease, the precision is higher. This trend can provide a reference for mechanism design of microcantilevers and microgrippers.
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JEON, HYEONG MIN, EUI BUM CHOI, JAE HOON HEO, and GWANG MOON EOM. "ANKLE JOINT MOMENTS IN DIFFERENT FOOT STRIKE METHODS DURING STAIR DESCENT." Journal of Mechanics in Medicine and Biology 19, no. 07 (November 2019): 1940031. http://dx.doi.org/10.1142/s0219519419400311.
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The purpose of this study was to compare the ankle joint moments in different foot strike patterns during stair descent and to find a better strategy. Methods: Twenty young subjects participated in this study. Subjects performed two trials of descending stairs in rearfoot strike (RFS) and forefoot strike (FFS) strategies. Kinematic and kinetic data were measured by a motion capture system and force plates. Ankle joint moments, ground reaction forces, and moment arms in three planes of motion were calculated from the measured data. The root-mean-squared means of ankle joint moments, ground reaction forces, and moment arms were compared between different foot strike patterns for each phase of stair descent (weight acceptance, forward continuance, and controlled lowering). Results: In the weight acceptance phase, FFS showed greater ankle joint moments than RFS in all three (dorsi/plantar-flexion, inversion/eversion, and internal/external rotation) directions ([Formula: see text]). In the forward continuance phase, FFS showed greater dorsi/plantar moments than RFS ([Formula: see text]). In controlled lowering phase, FFS showed smaller dorsi/plantar moments than RFS ([Formula: see text]). Discussion: The greater ankle joint moments of FFS in the weight acceptance phase were influenced by both the greater GRF magnitudes and greater moment arms. The greater dorsi/plantar moments of FFS in the forward continuance phase and the smaller dorsi/plantar moment of FFS in the controlled lowering phase were dominated by the greater moment arm and the smaller ground reaction force, respectively. RFS strategy resulted in smaller ankle joint moments in the majority of stair descent phases (weight acceptance and forward continuance), therefore, RFS would be a better strategy than FFS for stair descent in terms of ankle joint load.
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Johnson, C. D. "Identification of Unknown, Time-Varying Forces/Moments in Dynamics and Vibration Problems Using a New Approach To Deconvolution." Shock and Vibration 5, no. 3 (1998): 181–97. http://dx.doi.org/10.1155/1998/415028.
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In this paper an alternative approach to the classical deconvolution idea is used to obtain a new and practical method for real-time identification of unknown, time-varying forces/moments in a general class of linear (linearized) dynamics and vibration problems with multiple-inputs and multiple-measurements. This new method for force/moment identification is unique in the respect that the uncertainty in the force/moment time-variations is not characterized by random-process methods, but rather by a generalized spline-model with totally unknown weighting coefficients and completely known basis-functions. The basis-functions are custom chosen in each application to reflect, qualitatively, the known characteristics of the force/moment time-variations to be identified. The method does not involve explicit identification of the unknown weighting coefficients. General-purpose identification algorithms for both continuous-time and discrete-time measurements are developed, and a worked example including computer simulation results is presented.
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Wang, Zhi Yun, and Shou Ju Li. "Analytical Computational Models for Relationship between Ultimate Bending Moment of Concrete Segments and Axial Force." Key Engineering Materials 853 (July 2020): 177–81. http://dx.doi.org/10.4028/www.scientific.net/kem.853.177.
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Concrete segments are widely used to support soil and water loadings in shield-excavated tunnels. Concrete segments burden simultaneously to the loadings of bending moments and axial forces. Based on plane deformation assumption of material mechanics, in which plane section before bending remains plane after bending, ultimate bending moment model is proposed to compute ultimate bearing capacity of concrete segments. Ultimate bending moments of concrete segments computed by analytical models agree well with numerical simulation results by FEM. The accuracy of proposed analytical computational model for ultimate bending moment of concrete segments is numerically verified. The analytical computational model and numerical simulation for a practical engineering case indicate that the ultimate bending moment of concrete segments increases with increase of axial force on concrete segment in the case of large eccentricity compressive state.
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Ju, Shen Haw, and Hsin Hsiang Hsu. "Beam moment and shear force calculations using digital-camera experiments." Advances in Mechanical Engineering 11, no. 6 (June 2019): 168781401986067. http://dx.doi.org/10.1177/1687814019860675.
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This article presents an image-based method to find the beam moment and shear force using the measured beam displacements. A least-squares method is first developed to find the rotations and lateral displacements at beam ends using the measured displacements along the beam. Then, the moments and shear forces of this beam segment are obtained using the matrix formulation including shear deformation and large displacement effects. Two experimental schemes, image symbol dot and image-correlation methods, were used to validate the accuracy of the proposed scheme. The comparison of the results between the finite element analysis and the two methods shows acceptable accuracy. Although this method is mainly applied to the elastic region, one can still find the moment and shear force at the inelastic region using the equilibrium equation.
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Hashizume, Satoru, and Toshio Yanagiya. "A Forefoot Strike Requires the Highest Forces Applied to the Foot Among Foot Strike Patterns." Sports Medicine International Open 01, no. 02 (February 2017): E37—E42. http://dx.doi.org/10.1055/s-0042-122017.
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AbstractGround reaction force is often used to predict the potential risk of injuries but may not coincide with the forces applied to commonly injured regions of the foot. This study examined the forces applied to the foot, and the associated moment arms made by three foot strike patterns. 10 male runners ran barefoot along a runway at 3.3 m/s using forefoot, midfoot, and rearfoot strikes. The Achilles tendon and ground reaction force moment arms represented the shortest distance between the ankle joint axis and the line of action of each force. The Achilles tendon and joint reaction forces were calculated by solving equations of foot motion. The Achilles tendon and joint reaction forces were greatest for the forefoot strike (2 194 and 3 137 N), followed by the midfoot strike (1 929 and 2 853 N), and the rearfoot strike (1 526 and 2 394 N). The ground reaction force moment arm was greater for the forefoot strike than for the other foot strikes, and was greater for the midfoot strike than for the rearfoot strike. Meanwhile, there were no differences in the Achilles tendon moment arm among all foot strikes. These differences were attributed mainly to differences in the ground reaction force moment arm among the three foot strike patterns.
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Sepehri, Ali, and Kambiz Farhang. "Closed-Form Equations for Contact Force and Moment in Elastic Contact of Rough Surfaces." Modelling and Simulation in Engineering 2011 (2011): 1–14. http://dx.doi.org/10.1155/2011/739562.
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It is reasonable to expect that, when two nominally flat rough surfaces are brought into contact by an applied resultant force, they must support, in addition to the compressive load, an induced moment. The existence of a net applied moment would imply noneven distribution of contact force so that there are more asperities in contact over one region of the nominal area. In this paper, we consider the contact between two rectangular rough surfaces that provide normal and tangential contact force as well as contact moment to counteract the net moment imposed by the applied forces. The surfaces are permitted to develop slight angular misalignment, and thereby contact moment is derived. Through this scheme, it is possible to also define elastic contribution to friction since the half-plane tangential contact force on one side of an asperity is no longer balanced by the half-plane tangential force component on the opposite side. The elastic friction force, however, is shown to be of a much smaller order than the contact normal force. Approximate closed-form equations are found for contact force and moment for the contact of rough surfaces.
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Gysin, Priska, Terry R. Kaminski, Chris J. Hass, Cécile E. Grobet, and Andrew M. Gordon. "Effects of Gait Variations on Grip Force Coordination During Object Transport." Journal of Neurophysiology 100, no. 5 (November 2008): 2477–85. http://dx.doi.org/10.1152/jn.90561.2008.
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In object transport during unimpeded locomotion, grip force is precisely timed and scaled to the regularly paced sinusoidal inertial force fluctuations. However, it is unknown whether this coupling is due to moment-to-moment predictions of upcoming inertial forces or a longer, generalized time estimate of regularly paced inertial forces generated during the normal gait cycle. Eight subjects transported a grip instrument during five walking conditions, four of which altered the gait cycle. The variations included changes in step length (taking a longer or shorter step) or stepping on and over a stable (predictable) or unstable (unpredictable support surface) obstacle within a series of baseline steps, which resulted in altered frequencies and magnitudes of the inertial forces exerted on the transported object. Except when stepping on the unstable obstacle, a tight temporal coupling between the grip and inertial forces was maintained across gait variations. Precision of this timing varied slightly within the time window for anticipatory grip force control possibly due to increased attention demands related to some of the step alterations. Furthermore, subjects anticipated variations in inertial force when the gait cycle was altered with increases or decreases in grip force, relative to the level of the inertial force peaks. Overall the maintenance of force coupling and scaling across predictable walking conditions suggests that the CNS is able to anticipate changes in inertial forces generated by gait variations and to efficiently predict the grip force needed to maintain object stability on a moment-to-moment basis.
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Zhang, Yan Hua, Hua Xing Li, Deng Cheng Zhang, and Liang Qu. "The Effect of Nose Bluntness and Forebody Strakes on Aerodynamic Characteristics of Air-Launched Rocket Model." Applied Mechanics and Materials 391 (September 2013): 143–49. http://dx.doi.org/10.4028/www.scientific.net/amm.391.143.
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In this paper, the aerodynamic characteristics of the rocket model that might be used in a cabin air-launched system have been studied through experiments in low speed wind tunnel. The angle of incidence range is 0-80°, and the speed is 17m/s or 25m/s, including typical flight conditions prior to engine ignition. Forces and moments were measured through six-component balance. It is found that vortex asymmetry appears under certain condition with zero side slip. Asymmetrical phenomenon leads to larger side force and yaw moment, which can affect the trajectory of the rocket and put the carrier aircraft at risk. In addition, changes in regulation of the pitching moment with angle of attack are important to longitudinal stability, so the model with convergent-expanded afterbody was designed to improve stability. The effects of nose bluntness and forebody strakes on side force and yaw moment were presented, and the differences of aerodynamic characteristics with pointed and blunt nose, with and without forebody strakes were described. Results show that nose bluntness delays the appearance of asymmetric vortex, and the maximum side force is reduced by at least 50%. The forebody strakes reduce side force and yaw moment by weakening the asymmetric vortical interactions. The results can provide some references for designing the cabin air-launched rocket.
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Shim, Jae Kun, Mark L. Latash, and Vladimir M. Zatsiorsky. "Prehension Synergies in Three Dimensions." Journal of Neurophysiology 93, no. 2 (February 2005): 766–76. http://dx.doi.org/10.1152/jn.00764.2004.
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The goal of this study was to investigate the conjoint changes of digit forces/moments in 3 dimensions during static prehension under external torques acting on the object in one plane. The experimental paradigm was similar to holding a book vertically in the air where the center of mass of the book is located farther from the hand than the points of digit contacts. Three force and 3 moment components from each digit were recorded during static prehension of a customized handle. Subjects produced forces and moments in all 3 directions, although the external torques were exerted on the handheld object about only the Z-axis. The 3-dimensional response to a 2-dimensional task was explained by the cause–effect chain effects prompted by the noncollinearity of the normal forces of the thumb and the 4 fingers (represented by the “virtual finger”). Because the forces are not collinear (not along the same line), they generate moments of force about X- and Y-axes that are negated by the finger forces along the Y- and X-directions. The magnitudes of forces produced by lateral fingers (index and little) with longer moment arms were larger compared with the central fingers (middle and ring). At the virtual finger (an imaginary digit whose mechanical action is equivalent to the summed action of the 4 fingers) level, the relative contribution of different fractions of the resistive moment produced by subjects did not depend on the torque magnitude. We conclude that the CNS 1) solves a planar prehension task by producing forces and moments in all 3 directions, 2) uses mechanical advantage of fingers, and 3) shares the total torque among finger forces and moments in a particular way disregarding the torque magnitude.
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Koblauch, Henrik, Thomas Heilskov-Hansen, Tine Alkjær, Erik B. Simonsen, and Marius Henriksen. "The Effect of Foot Progression Angle on Knee Joint Compression Force During Walking." Journal of Applied Biomechanics 29, no. 3 (June 2013): 329–35. http://dx.doi.org/10.1123/jab.29.3.329.
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It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study was to investigate the knee joint compressive forces during walking with internal, external and normal foot rotation and to determine if the frontal plane knee joint moment is an adequate surrogate for the compression forces in the medial and lateral knee joint compartments under such gait modifications. Ten healthy males walked at a fixed speed of 4.5 km/h under three conditions: Normal walking, internally rotated and externally rotated. All gait trials were recorded by six infrared cameras. Net joint moments were calculated by 3D inverse dynamics. The results revealed that the medial knee joint compartment compression force increased during external foot rotation and the lateral knee joint compartment compression force increased during internal foot rotation. The increases in joint loads may be a result of increased knee flexion angles. Further, these data suggest that the frontal plane knee joint moment is not a valid surrogate measure for knee joint compression forces but rather indicates the medial-to-lateral load distribution.
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Felicita, A. Sumathi. "Quantification of intrusive/retraction force and moment generated during en-masse retraction of maxillary anterior teeth using mini-implants: A conceptual approach." Dental Press Journal of Orthodontics 22, no. 5 (October 2017): 47–55. http://dx.doi.org/10.1590/2177-6709.22.5.047-055.oar.
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ABSTRACT Objective: The aim of the present study was to clarify the biomechanics of en-masse retraction of the upper anterior teeth and attempt to quantify the different forces and moments generated using mini-implants and to calculate the amount of applied force optimal for en-masse intrusion and retraction using mini-implants. Methods: The optimum force required for en-masse intrusion and retraction can be calculated by using simple mathematical formulae. Depending on the position of the mini-implant and the relationship of the attachment to the center of resistance of the anterior segment, different clinical outcomes are encountered. Using certain mathematical formulae, accurate measurements of the magnitude of force and moment generated on the teeth can be calculated for each clinical outcome. Results: Optimum force for en-masse intrusion and retraction of maxillary anterior teeth is 212 grams per side. Force applied at an angle of 5o to 16o from the occlusal plane produce intrusive and retraction force components that are within the physiologic limit. Conclusion: Different clinical outcomes are encountered depending on the position of the mini-implant and the length of the attachment. It is possible to calculate the forces and moments generated for any given magnitude of applied force. The orthodontist can apply the basic biomechanical principles mentioned in this study to calculate the forces and moments for different hypothetical clinical scenarios.
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Neumann, Edward Schreiber, Kartheek Yalamanchili, Justin Brink, and Joon S. Lee. "Transducer-based comparisons of the prosthetic feet used by transtibial amputees for different walking activities: a pilot study." Prosthetics and Orthotics International 36, no. 2 (February 17, 2012): 203–16. http://dx.doi.org/10.1177/0309364612436408.
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Background: Knowledge of transtibial residual limb force and moment loading during gait can be clinically useful. The research question was whether a transducer attached between the socket and pylon can be used to detect differences in loading patterns created by prosthetic feet of different design and different walking activities in real-world environments outside the gait lab. Objectives: To develop methods for obtaining, processing, analyzing and interpreting transducer measurements and examining their clinical usefulness. Study Design: Case series design. Methods: A convenience sample of four K3-K4 transtibial amputees and a wireless tri-axial transducer mounted distal to the socket. Activities included self-selected comfortable speed walking, and ascending and descending ramps and steps. Measurements taken about three orthogonal axes were processed to produce plots of normalized resultant force versus normalized resultant moment. Within-subject differences in peak resultant forces and moments were tested. Results: Loading patterns between feet and subjects and among the activities were distinctly different. Optimal loading of peak resultant forces tentatively might occur around 25% and 69% to73% of stance during self-selected comfortable walking. Ascending and descending ramps is useful for examining heel and forefoot response. Conclusions: Force-moment plots obtained from transducer data may assist clinical decision making. Clinical relevance A pylon-mounted transducer distal to the socket reveals the moments and forces transmitted to the residual limb and can be used to evaluate the loading patterns on the residual limb associated with different foot designs and different everyday activities outside the gait lab.
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Crisco, Joseph J., Nikolas J. Osvalds, and Michael J. Rainbow. "The Kinetics of Swinging a Baseball Bat." Journal of Applied Biomechanics 34, no. 5 (October 1, 2018): 386–91. http://dx.doi.org/10.1123/jab.2017-0337.
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The purpose of this study was to compute the 3-dimensional kinetics required to swing 3 youth baseball bats of varying moments of inertia. The 306 swings by 22 male players (age 13–18 y) were analyzed. Inverse dynamics with respect to the batter’s hands were computed given the known kinematics and physical properties of the bats. Peak force increased with larger bat moments of inertia and was strongly correlated with bat tip speed. By contrast, peak moments were weakly correlated with bat moments of inertia and bat tip speed. Throughout the swing, the force applied to the bat was dominated by a component aligned with the long axis of the bat and directed away from the bat knob, whereas the moment applied to the bat was minimal until just prior to ball impact. These results indicate that players act to mostly “pull” the bat during their swing until just prior to ball impact, at which point they rapidly increase the moment on the bat. This kinetic analysis provides novel insight into the forces and moments used to swing baseball bats.
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Steiner, Ethan, and Katherine A. Boyer. "Variable Stiffness Shoes for Knee Osteoarthritis: An Evaluation of 3-Dimensional Gait Mechanics and Medial Joint Contact Forces." Journal of Applied Biomechanics 38, no. 2 (April 1, 2022): 117–25. http://dx.doi.org/10.1123/jab.2021-0217.
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The study aim was to quantify the impact of a commercially available variable stiffness shoe (VSS) on 3-dimensional ankle, knee, and hip mechanics and estimated knee contact forces compared with a control shoe. Fourteen participants (10 females) with knee osteoarthritis completed gait analysis after providing informed consent. Shoe conditions tested were control shoe (New Balance MW411v2) and VSS (Abeo SMART3400). An OpenSim musculoskeletal model with static optimization was used to estimate knee contact forces. There were no differences in joint kinematics or in the knee adduction or flexion moments (P = .06; P = .2). There were increases in the knee internal and external rotation (P = .02; P = .03) and hip adduction and internal rotation moments for VSS versus control (P = .03; P = .02). The estimated contact forces were not different between shoes (total P = .3, medial P = .1, and lateral P = .8), but contact force changes were correlated with changes in the knee adduction moment (medial r2 = .61; P < .007). High variability in knee flexion moment changes and increases in the internal rotation moment combined with small decreases in the knee adduction moment did not lead to decreases in estimated contact forces. These results suggest that evaluation of VSS using only the knee adduction moment may not adequately capture its impact on osteoarthritis.
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Martin, Philip E., and Gary D. Heise. "Archery Bow Grip Force Distribution: Relationships with Performance and Fatigue." International Journal of Sport Biomechanics 8, no. 4 (November 1992): 305–19. http://dx.doi.org/10.1123/ijsb.8.4.305.
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Archery instructors believe that force distribution (FD) between the hand and bow grip can have a considerable effect on arrow flight, but there is no empirical support for this speculation. This study examined FD on the bow grip in experienced archers and explored the possible relationships between FD, performance, and fatigue. FD was quantified for 15 experienced archers (8 highly skilled [HS] and 7 less skilled [LS]) using 15 unobtrusive force sensors as each archer completed 72 shots. Arrow position relative to the target center, estimated net moments and moment arms about vertical and horizontal axes through the grip, and shot-to-shot variability in the estimated moments and moment arms were computed for three blocks of six shots. Results demonstrated that (a) estimated moments and moment arms were not consistently related to observed vertical or horizontal deviations in arrow position, (b) there were no systematic differences in FD between HS and LS archers, (c) fatigue had no quantifiable effect on FD, and (d) HS archers displayed less shot-to-shot variability in vertical FD than LS archers, but similar variability horizontally. Results did not support the above-noted common belief of archery instructors.
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San Andres, Luis. "The Effect of Journal Misalignment on the Operation of a Turbulent Flow Hydrostatic Bearing." Journal of Tribology 115, no. 3 (July 1, 1993): 355–63. http://dx.doi.org/10.1115/1.2921643.
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An analysis for calculation of the dynamic force and moment response in turbulent flow, orifice compensated hydrostatic journal bearings is presented. The fully developed flow of a barotropic liquid is described by variable properties, bulk-flow equations and local turbulent friction factors based on bearing surface condition. Bearing load and moments and, dynamic force and moment coefficients are calculated for perturbations in journal center displacements and misaligned journal axis rotations. Numerical results for the effect of static misalignment angles in the plane of the eccentricity vector are presented for a water lubricated hydrostatic bearing. The predictions show that journal axis misalignment causes a reduction in load capacity due to loss in film thickness, increases the flow rate and produces significant restoring moments (couples). Force and moment coefficients due to dynamic journal axis rotations are also discussed.
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I Wayan Wirya Aristyana and Muhammad Fauzan. "Analisis dan Desain Struktur Atas Hotel 10 Lantai di Kabupaten Bogor terhadap Beban Gempa." Jurnal Teknik Sipil dan Lingkungan 6, no. 1 (April 28, 2021): 1–10. http://dx.doi.org/10.29244/jsil.6.1.1-10.
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The type of soil at the location of the hotel building is a type of medium land (D). The applications used in this study are ETABS V16.1 and AutoCAD. Based on the PUSKIM website, the Ss and S1 Bogor City were 0.881 and 0.356, respectively. Based on the results of the analysis of the application ETABS V16.1 obtained fewer reinforcement design results than the existing reinforcement. The maximum nominal moment of the beam is 508.3 kNm while the ultimate moment is 498.4 kNm. The maximum nominal shear force of the beam is 565.9 kN while the ultimate shear force is 538.4 kN. The maximum nominal moment of the column is 1488.5 kNm while the maximum ultimate moment is 1478 kNm. The maximum nominal axial force of the column is 6291 kN while the maximum ultimate axial force is 6287 kN. The maximum nominal bending moment of the floor plate is 41.3 kNm while the maximum ultimate moment is 39.9 kNm. The maximum nominal shear force of the floor plate is 234.7 kN while the maximum ultimate shear force is 228.9 kN. The nominal shear force of shear wall is 8238.5 kN while the ultimate shear force is 8194.7 kN. Based on the internal forces, the building that has been built is in accordance with the plan so that it is safe to withstand earthquake loads.
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Putra, Risal Ardiansyah, Fachri Almawali A F, and Widya Utama. "MODELLING 2-D PONDASI JEMBATAN BERDASARKAN PEMBEBANAN DAN LETAK POSISI BATUAN ‘X’." PROKONS Jurusan Teknik Sipil 14, no. 1 (June 14, 2020): 13. http://dx.doi.org/10.33795/prokons.v14i1.226.
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This paper contains an analysis of the loading and the position of rock in the bridge foundation based on the rock's response to the force that will be tested with "Graphic User Interface (GUI)" program using MATLAB. This paper also explains the preparation of bridge foundation modeling based on the forces tested on the rock named ‘x’. The response forces discussed in this paper are normal force, latitude force and moment force. The data is processed using MATLAB software and then presented in the form of tables, graphs and 2D modeling that shows the loading and the position of rocks correspondence to the bridge foundation. After obtaining the rock’s ‘x’ data, the data is then processed using Graphic User Interface program, through the program moment force graphs, normal force graphs, latitude graphs can be obtained which later these results can be considered for modeling the loading and the position of the rock’s ‘x’. Through the data processing that has been done, zero normal force is obtained, and the latitude has a value of about (0 to 8) N and the moment force of about (-60 to 0) N. Based on these calculations it was found that the rock’s 'x' can be modeled by arranging it rectangle with center of gravity evenly distributed at the center. And the model that are used is the placement pinch model because it does not have translational and rotational values so that the rock ‘x’ is suitable to be the bridge's foundation.Keywords: Shear forces, Bending Moment, Normal Forces, GUI, Modelling
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Nazila, Kamila Shaomi, and Kamaludin Kamaludin. "Pembesaran Gaya Dalam dan Rasio Kekuatan Elemen Struktur Baja untuk berbagai Zona Gempa di Indonesia. (Hal. 74-84)." RekaRacana: Jurnal Teknil Sipil 5, no. 1 (March 29, 2019): 74. http://dx.doi.org/10.26760/rekaracana.v5i1.74.
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ABSTRAKStruktur bangunan dapat dikatakan kuat jika dapat memikul semua beban salah satunya, beban gempa. Waktu mendesain struktur akibat beban gempa lebih lama daripada akibat beban tanpa gempa. Penelitian ini bertujuan untuk memprediksi pembesaran gaya dalam dan prediksi rasio kekuatan pada struktur akibat adanya beban tanpa gempa. Penelitian ini dilakukan terhadap gedung 10 lantai dengan material baja. Tujuh model variasi beban pada gedung sebagai berikut: beban tanpa gempa,beban tanpa gempa dan percepatan 0,2 ; 0,4 ; 0,6 ; 0,8 ; 1,0 ; juga 1,2 . Analisis gaya dalam dan pengecekan kekuatan struktur bangunan menggunakan software ETABS 2015. Hasil yang diperoleh pada balok yaitu, gaya lentur ( ) dengan pembesaran momen maksimum kurang lebih 0,9 kali terhadap momen akibat beban tanpa gempa. Pembesaran momen relatif antar variasi beban kurang lebih 1,2. Hal ini mengakibatkan rasio untuk desain awal kurang lebih 30% untuk daerah gempa kuat.Kata kunci: struktur baja, beban gempa, pembesaran momen, pembesaran rasio. ABSTRACTThe structure of the building can be said to be strong if it can carry all the loads, such as the earthquake loads. Time to design structures due to earthquake loads is longer than without earthquakes loads. This study aims to predict the magnification of internal forces and the ratio of strength to structures due to without earthquake loads. This research was conducted on 10-storysteel building. Seven models of load variations in the building are as follows: load without earthquake, load without earthquake and acceleration of 0.2 , 0.4 , 0.6 , 0.8 , 1.0 , and 1.2 . The internal force analysis and checking of building structure strengthare using ETABS 2015. The results obtained that flexural force ( ) with a maximum moment magnification of approximately 0.9 times the moment due to without earthquake loads on the beam. Enlargement of relative moments between load variations is approximately 1.2. Therefore, ratio of the initial design is approximately 30% for strong earthquake areas. Keywords: steel structure, earthquake load, moment magnification, ratio enlargement.
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Shintcovsk, Ricardo Lima, Roberto Soares da Silva Júnior, Larry White, Lidia Parsekian Martins, and Renato Parsekian Martins. "Evaluation of the load system produced by a single intrusion bend in a maxillary lateral incisor bracket with different alloys." Angle Orthodontist 88, no. 5 (May 15, 2018): 611–16. http://dx.doi.org/10.2319/081717-556.1.
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ABSTRACT Objectives: To evaluate if a 0.5-mm vertical bend applied on an incisor bracket produces movements in other planes and if different wires influence these effects. Materials and Methods: An acrylic model of a treated patient with brackets passively bonded was attached to an Orthodontic Force Tester, and a load cell was attached to the left lateral incisor. Thirty 0.019 × 0.025-inch archwires were divided into three groups according to their alloy: SS (stainless steel), B-Ti (beta-titanium), and MF (beta-titanium wire coated with nickel-titanium). Step-bends of 0.5 mm high were placed on the lateral incisor bracket using a universal plier, and the forces and moments in three dimensions were statistically analyzed by analysis of variance and Tukey post hoc test. Results: SS produced a larger force (3.4 N) than the B-Ti (1.41 N) and the MF (0.53 N; P < .001). Lingual forces were produced by the SS (0.82 N) and B-Ti (0.31 N) groups, while in the MF group, the force was insignificant. SS produced a mesial force of 0.24 N, while the B-Ti force was insignificant and MF produced 0.09 N. Groups produced different crown-distal tipping moments (SS = 31.48 N-mm, B-Ti = 11.7 N-mm, and MF = 4.55 N-mm) and different crown-buccal tipping moments. SS produced larger moments (3.63 N-mm) than B-Ti (1.02 N-mm) and MF (0.36 N-mm) wires. A mesial-out rotational moment was observed in all groups (SS = 7.17 N-mm, B-Ti = 3.46 N-mm, and MF = 0.86 N-mm). Conclusions: A 0.5-mm intrusion bend produced lingual and mesial side effects. In addition to the distal and buccal crown-tipping moments, there was a mesial-out moment. Compared with SS, B-Ti and MF wires produced lower forces. These more flexible wires showed side effects with lesser intensity.
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Kolesnichenko, Ilya V., Andrey D. Mamykin, and Ruslan I. Khalilov. "Electromagnetic liquid metal stirrer: verification of the electromagnetic part of the problem." ВЕСТНИК ПЕРМСКОГО УНИВЕРСИТЕТА. ФИЗИКА, no. 4 (2022): 45–51. http://dx.doi.org/10.17072/1994-3598-2022-4-45-51.
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We studied a numerical model describing electromagnetic forces that arise in a cylindrical volume of metal placed in the working area of a newly designed electromagnetic stirrer. The combined use of a complex-shaped inductor with a set of 6x6 coils and a power management system makes it possible to generate magnetic fields of almost any topology (in the simplest case, traveling and rotating magnetic fields). To verify the numerical model, we created an experimental setup consisting of an inductor and measuring systems. A good agreement has been achieved between the experimental and numerical data on the distribution of the magnetic field and the magnitude of the generated electromagnetic forces. In particular, the maximum of the curve showing dependence of the moment of the electromagnetic force on the frequency of alternating current is reproduced with good accuracy. The effect of rotation of an electrically conductive medium on the moment of the electromagnetic force acting on this medium was studied numerically. By analyzing the extrema of the moments of electromagnetic forces, we have found the dependence of the frequency of the supply voltage of the windings, which ensures the maximum moment of electromagnetic forces during the rotation of the electrically conductive medium, on the rotation frequency of the medium.
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Papadopoulos, E., and A. Abu-Abed. "On the Design of Zero Reaction Manipulators." Journal of Mechanical Design 118, no. 3 (September 1, 1996): 372–76. http://dx.doi.org/10.1115/1.2826895.
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In a number of industrial, space, or mobile applications, reaction forces and moments transmitted by a manipulator to its base are undesirable. In this paper, we analyze the problem of force and torque transmission in robotic systems, and propose design and planning methods that can eliminate it, or reduce it. Based on force and moment transmission analysis, a three DOF redundant manipulator design is selected. Dynamic reaction forces are eliminated by force balancing. Reaction moments are eliminated by following reactionless paths, whose planning is simplified by rendering the dynamics configuration-invariant. Reactionless Workspaces are defined in which any end-effector path can result in zero dynamic reactions. An example is used to demonstrate the usefulness of the proposed methods. An important advantage of these methods is that the manipulator can be used either as a redundant, or as a reduced DOF reactionless system.
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Ueno, Ryo, Alessandro Navacchia, Nathaniel A. Bates, Nathan D. Schilaty, Aaron J. Krych, and Timothy E. Hewett. "Analysis of Internal Knee Forces Allows for the Prediction of Rupture Events in a Clinically Relevant Model of Anterior Cruciate Ligament Injuries." Orthopaedic Journal of Sports Medicine 8, no. 1 (January 1, 2020): 232596711989375. http://dx.doi.org/10.1177/2325967119893758.
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Background: A recently developed mechanical impact simulator induced an anterior cruciate ligament (ACL) rupture via the application of a combination of inverse dynamics–based knee abduction moment (KAM), anterior tibial shear force (ATS), and internal tibial rotation moment with impulsive compression in a cohort of cadaveric limbs. However, there remains an opportunity to further define the interaction of internal forces and moments at the knee and their respective influence on injury events. Purpose: To identify the influence of internal knee loads on an ACL injury event using a cadaveric impact simulator. Study Design: Controlled laboratory study. Methods: Drop-landing simulations were performed and analyzed on 30 fresh-frozen cadaveric knees with a validated mechanical impact simulator. Internal forces and moments at the knee joint center were calculated using data from a 6-axis load cell recorded on the femur during testing. Kinetic data from a total of 1083 trials that included 30 ACL injury trials were used as inputs for principal component (PC) analysis to identify the most critical features of loading waveforms. Logistic regression analysis with a stepwise selection was used to select the PCs that predicted an ACL injury. Injurious waveforms were reconstructed with selected PCs in logistic regression analysis. Results: A total of 3 PCs were selected in logistic regression analysis that developed a significant model ( P < .001). The external loading of KAM was highly correlated with PC1 (ρ < –0.8; P < .001), which explained the majority (>69%) of the injurious waveforms reconstructed with the 3 selected PCs. The injurious waveforms demonstrated a larger internal knee adduction moment and lateral tibial force. After the ACL was ruptured, decreased posterior tibial force was observed in injury trials. Conclusion: These findings give us a better understanding of ACL injury mechanisms using 6-axis kinetics from an in vitro simulator. An ACL rupture was correlated with an internal knee adduction moment (external KAM) and was augmented by ATS and lateral tibial force induced by an impact, which distorted the ACL insertion orientation. Clinical Relevance: The ACL injury mechanism explained in this study may help target injury prevention programs to decrease injurious knee loading (KAM, ATS, and lateral tibial force) during landing tasks.
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Hong, Jangho, and Motoji Yamamoto. "A calculation method of the reaction force and moment for a Delta-type parallel link robot fixed with a frame." Robotica 27, no. 4 (July 2009): 579–87. http://dx.doi.org/10.1017/s0263574708004967.
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SUMMARYThe paper presents a method of reaction force and moment calculation for a 3-RSS pure translational parallel link robot (Delta-type parallel robot), in which the inverse and forward kinematics of the parallel link robot are directly analyzed according to kinematic structure of the parallel robot. For dynamic analysis, the parallel robot is imaginarily parted into three serial ones, and their actual joint torques are determined by the virtual work principle. To obtain the reaction force and moment of the parallel robot acting on the base, which is the composition of the reaction forces and moments of the three serial robots, the Newton–Euler Method is adopted. To show the validity of the presented method, the simulation analysis and experimental results are given, the experimental results tally with the calculation value.
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Puel, A., and D. D. Loriggio. "Numerical analysis of symmetrical and asymmetrical reinforced concrete flat slabs - an integrated slab/ column analysis." Revista IBRACON de Estruturas e Materiais 9, no. 3 (June 2016): 306–56. http://dx.doi.org/10.1590/s1983-41952016000300002.
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ABSTRACT This paper studies the modeling of symmetric and asymmetric flat slabs, presenting alternatives to the problem of singularity encountered when the slab is modeled considering columns as local support. A model that includes the integrated slab x column analysis was proposed, distributing the column reactions under the slab. The procedure used transforms the bending moment and column axial force in a distributed load, which will be applied to the slab in the opposite direction of gravitational loads. Thus, the bending moment diagram gets smooth in the punching region with a considerable reduction of values, being very little sensible to the variation of used mesh. About the column, it was not seen any significant difference in the axial force, although the same haven't occurred with the bending moments results. The final part of the work uses geoprocessing programs for a three-dimensional view of bending moments, allowing a new comprehension the behavior of these internal forces in the entire slab.
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Van Gheluwe, Bart, Kevin A. Kirby, and Friso Hagman. "Effects of Simulated Genu Valgum and Genu Varum on Ground Reaction Forces and Subtalar Joint Function During Gait." Journal of the American Podiatric Medical Association 95, no. 6 (November 1, 2005): 531–41. http://dx.doi.org/10.7547/0950531.
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The mechanical effects of genu valgum and varum deformities on the subtalar joint were investigated. First, a theoretical model of the forces within the foot and lower extremity during relaxed bipedal stance was developed predicting the rotational effect on the subtalar joint due to genu valgum and varum deformities. Second, a kinetic gait study was performed involving 15 subjects who walked with simulated genu valgum and genu varum over a force plate and a plantar pressure mat to determine the changes in the ground reaction force vector within the frontal plane and the changes in the center-of-pressure location on the plantar foot. These results predicted that a genu varum deformity would tend to cause a subtalar pronation moment to increase or a supination moment to decrease during the contact and propulsion phases of walking. With genu valgum, it was determined that during the contact phase a subtalar pronation moment would increase, whereas in the early propulsive phase, a subtalar supination moment would increase or a pronation moment would decrease. However, the current inability to track the spatial position of the subtalar joint axis makes it difficult to determine the absolute direction and magnitudes of the subtalar joint moments. (J Am Podiatr Med Assoc 95(6): 531–541, 2005)
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Zheng, Xiao-Xia, and Wei-Feng Sun. "Magnetic Force Probe Characterizations of Nanoscaled Ferromagnetic Domains: Finite-Element Magnetostatic Simulations." Nanomaterials 12, no. 13 (June 28, 2022): 2212. http://dx.doi.org/10.3390/nano12132212.
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Microscopic characterization of magnetic nanomaterials by magnetic probe interacting with ferromagnetic nano-domains is proposed according to finite-element magnetostatic field simulations. Magnetic forces detected by microscopic probe are systematically investigated on magnetic moment orientation, magnetization intensity and geometry of ferromagnetic nano-domains, and especially on permanent magnetic coating thickness and tilting angle of probe, to provide a theoretical basis for developing magnetic force microscopy. Magnetic force direction is primarily determined by magnetic moment orientation of nanosample, and the tip curvature dominates magnetic force intensity that is meanwhile positively correlated with nanosample magnetization and probe magnetic coating thickness. Nanosample should reach a critical thickness determined by its transverse diameter to be capable of accurately detecting the magnetic properties of ferromagnetic nanomaterials. Magnetic force signal relies on probe inclination when the sample magnetic moment is along probe tilting direction, which, however, is not disturbed by probe inclination when sample magnetic moment is perpendicular to probe tilting plane. Within the geometry of satisfying a critical size requirement, the magnetic force can successfully image the ferromagnetic nano-domains by characterizing their sizes and magnetic moment orientations. The present study is expected to provide effective analyzing schemes and theoretical evidences for magnetic force microscopy of characterizing magnetic structures in ferromagnetic nanomaterials.