The Nonlinear String Under a Vertical Force

1969 ◽  
Vol 17 (1) ◽  
pp. 172-178 ◽  
Author(s):  
R. W. Dickey
Keyword(s):  
Vertical Force ◽  
Nonlinear String

Force Plate Analysis of Dogs with Bilateral Hip Dysplasia Treated with a Unilateral Triple Pelvic Osteotomy: A Long-term Review of Cases

1998 ◽  
Vol 11 (02) ◽  
pp. 85-93 ◽  
Author(s):  
Joanne R. Cockshutt ◽  
H. Dobson ◽  
C. W. Miller ◽  
D. L. Holmberg ◽  
Connie L. Taves ◽  
...  
Keyword(s):  
Gait Analysis ◽  
Hip Dysplasia ◽  
Weight Bearing ◽  
Force Plate ◽  
Case Series ◽  
Pelvic Osteotomy ◽  
Vertical Force ◽  
Long Term Outcome ◽  
Case Series Study

SummaryA retrospective case series study was done to determine the long-term outcome of operations upon dogs treated for canine hip dysplasia by means of a triple pelvic osteotomy (TPO). Twentyfour dogs with bilateral hip dysplasia, that received a unilateral TPO between January 1988 and June 1995, were re-examined at the Ontario Veterinary College. The assessment included physical, orthopedic and lameness examinations, standard blood work, pelvic radiographs and force plate gait analysis. They were compared to bilaterally dysplastic dogs that had not been treated, and also to normal dogs. Force plate data analysis demonstrated a significant increase in peak vertical force (PVF) and mean vertical force over stance (MVF) in the limb that underwent surgical correction by means of a TPO, when compared to the unoperated hip. It was determined that performing a unilateral TPO on a young dysplastic dog resulted in greater forces and weight bearing being projected through the TPO corrected limb when compared to the unoperated limb.Dogs with bilateral hip dysplasia treated with a unilateral triple pelvic osteotomy (TPO) were assessed by force plate gait analysis, radiographs and orthopedic examination. There was a significant increase in hip Norberg angles over time, although degenerative changes did progress. Limbs that had been operated upon had significantly greater peak and mean ground reaction forces than limbs that had not received an operation.

Fore-Aft Forces in Tire-Wheel Assemblies Generated by Unbalances and the Influence of Balancing

1991 ◽  
Vol 19 (3) ◽  
pp. 142-162 ◽  
Author(s):  
D. S. Stutts ◽  
W. Soedel ◽  
S. K. Jha
Keyword(s):  
Mathematical Model ◽  
Elastic Foundation ◽  
Torsional Oscillation ◽  
Vertical Direction ◽  
Torsional Stiffness ◽  
Rolling Motion ◽  
Vertical Force ◽  
Horizontal Force ◽  
Wheel Rim ◽  
Open Question

Abstract When measuring bearing forces of the tire-wheel assembly during drum tests, it was found that beyond certain speeds, the horizontal force variations or so-called fore-aft forces were larger than the force variations in the vertical direction. The explanation of this phenomenon is still somewhat an open question. One of the hypothetical models argues in favor of torsional oscillations caused by a changing rolling radius. But it appears that there is a simpler answer. In this paper, a mathematical model of a tire consisting of a rigid tread ring connected to a freely rotating wheel or hub through an elastic foundation which has radial and torsional stiffness was developed. This model shows that an unbalanced mass on the tread ring will cause an oscillatory rolling motion of the tread ring on the drum which is superimposed on the nominal rolling. This will indeed result in larger fore-aft than vertical force variations beyond certain speeds, which are a function of run-out. The rolling motion is in a certain sense a torsional oscillation, but postulation of a changing rolling radius is not necessary for its creation. The model also shows the limitation on balancing the tire-wheel assembly at the wheel rim if the unbalance occurs at the tread band.

Studies on Related ms Magnitude Rate Models in Triangular Wave Unloading Section of Calcium Medium-Fine Sandstone

2010 ◽  
Vol 152-153 ◽  
pp. 164-170
Author(s):  
Jie Liu ◽  
Jian Lin Li ◽  
Ying Xia Li ◽  
Shan Shan Yang ◽  
Ji Fang Zhou ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Strain Curve ◽  
Experimental System ◽  
Constant Term ◽  
Lag Time ◽  
Vertical Force ◽  
Time Segment ◽  
Triangular Wave ◽  
Apparent Modulus ◽  
The Impact

Specific to the improvement in the present research of mechanical response under cyclic loading, this paper, taking the calcareous middle- coarse sandstone as the research subject and the RMT-150C experimental system in which data is recoded by ms magnitude as the platform, develops several related models concerning the unloading rate of triangle waves. The unloading process is divided into lag time segment and non-lag time segment, with criterions and related parameters provided as well. The term apparent elastic modulus is defined. The test data analysis shows that there exist a linear relationship between the apparent modulus and instant vertical force before load damage in non-lag time segment. On the preceding basis, a rate-dependent model of triangular wave un-installation section in non-lag time segment is established. Due to the inability of the loading equipment to accurately input the triangle wave, the average loading rate is amended and a constant term is added into it. The model is proved to be reliable, as the predicted value of the deformation rate and the stress strain curve coincides with measured value. At the same time, the impact of the lag time is pointed out quantitatively and a predication model of lag time segment is set up.

Using a saddle-assistive device equipped with mechanical orthosis for walking of the person with incomplete spinal cord injury

2021 ◽  
pp. 095441192110201
Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reaction Force ◽  
Assistive Devices ◽  
Assistive Device ◽  
Walking Ability ◽  
Vertical Force ◽  
Incomplete Spinal Cord Injury ◽  
Combined Application ◽  
Cord Injury

The majority of the people with incomplete spinal cord injury lose their walking ability, due to the weakness of their muscle motors in providing torque. As a result, developing assistive devices to improve their conditionis of great importance. In this study, a combined application of the saddle-assistive device (S-AD) and mechanical medial linkage or thosis was evaluated to improve the walking ability in patients with spinal cord injury in the gait laboratory. This mobile assistive device is called the saddle-assistive device equipped with medial linkage or thosis (S-ADEM). In this device, a mechanical orthosis was used in a wheeled walker as previously done in the literature. Initially, for evaluation of the proposed assistive device, the experimental results related to the forces and torques exerted on the feet and upper limbs of a person with the incomplete Spinal Cord Injury (SCI) during walking usingthe standard walker were compared with an those obtained from using the S-ADEM on an able-bodied subject. It was found that using this combination of assistive devices decreases the vertical force and torque on the foot at the time of walking by 53% and 48%, respectively compared to a standard walker. Moreover, the hand-reaction force on the upper limb was negligible instanding and walking positions usingthe introduced device. The findings of this study revealed that the walking ability of the patients with incomplete SCI was improved using the proposed device, which is due to the bodyweight support and the motion technology used in it.

Vertical force generation of a vectorial thruster that employs a rigid flapping panel

2021 ◽  
Vol 33 (6) ◽  
pp. 061906
Author(s):  
Haizhou Hu ◽  
Yankui Wang
Keyword(s):  
Force Generation ◽  
Vertical Force

scholarly journals Lower Extremity Biomechanics Predicts Major League Baseball Player Performance

2021 ◽  
Vol 9 (7) ◽  
pp. 232596712110152
Author(s):  
Lucas G. Teske ◽  
Edward C. Beck ◽  
Garrett S. Bullock ◽  
Kristen F. Nicholson ◽  
Brian R. Waterman
Keyword(s):  
Lower Extremity ◽  
Major League Baseball ◽  
Reaction Force ◽  
Regression Trees ◽  
Minimal Detectable Change ◽  
Vertical Force ◽  
Baseball Players ◽  
Major League ◽  
Lower Extremity Biomechanics ◽  
Statistical Metrics

Background: Although lower extremity biomechanics has been correlated with traditional metrics among baseball players, its association with advanced statistical metrics has not been evaluated. Purpose: To establish normative biomechanical parameters during the countermovement jump (CMJ) among Major League Baseball (MLB) players and evaluate the relationship between CMJ-developed algorithms and advanced statistical metrics. Study Design: Cohort study; Level of evidence, 3. Methods: MLB players in 2 professional organizations performed the CMJ at the beginning of each baseball season from 2013 to 2017. We collected ground-reaction force data including the eccentric rate of force development (“load”), concentric vertical force (“explode”), and concentric vertical impulse (“drive”) as well as the Sparta Score. The advanced statistical metrics from each baseball season (eg, fielding independent pitching [FIP], weighted stolen base runs [wSB], and weighted on-base average) were also gathered for the study participants. The minimal detectable change (MDC) was calculated for each CMJ variable to establish normative parameters. Pearson coefficient analysis and regression trees were used to evaluate associations between CMJ data and advanced statistical metrics for the players. Results: A total of 151 pitchers and 138 batters were included in the final analysis. The MDC for “load,” “explode,” “drive,” and the Sparta Score was 10.3, 8.1, 8.7, and 4.6, respectively, and all demonstrated good reliability (intraclass correlation coefficient > 0.75). There was a weak but statistically significant correlation between the Sparta Score and wSB ( r = 0.23; P = .007); however, there were no significant correlations with any other advanced metrics. Regression trees demonstrated superior FIP with higher Sparta Scores in older pitchers compared with younger pitchers. Conclusion: There was a positive but weak correlation between the Sparta Score and base-stealing performance among professional baseball players. Additionally, older pitchers with a higher Sparta Score had statistically superior FIP compared with younger pitchers with a similar Sparta Score after adjusting for age.

scholarly journals Design, Analysis and Application of Single-Wheel Test Bench for All-Electric Antilock Braking System in Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1294
Author(s):  
Xiangdang XUE ◽  
Ka Wai Eric CHENG ◽  
Wing Wa CHAN ◽  
Yat Chi FONG ◽  
Kin Lung Jerry KAN ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Test Bench ◽  
Potential Candidate ◽  
Vertical Force ◽  
Abs Algorithms ◽  
Braking System ◽  
Vehicle Velocity ◽  
Antilock Braking System ◽  
Antilock Braking ◽  
Electromechanical Brake

An antilock braking system (ABS) is one of the most important components in a road vehicle, which provides active protection during braking, to prevent the wheels from locking-up and achieve handling stability and steerability. The all-electric ABS without any hydraulic components is a potential candidate for electric vehicles. To demonstrate and examine the all-electric ABS algorithms, this article proposes a single-wheel all-electric ABS test bench, which mainly includes the vehicle wheel, the roller, the flywheels, and the electromechanical brake. To simulate dynamic operation of a real vehicle’s wheel, the kinetic energy of the total rotary components in the bench is designed to match the quarter of the one of a commercial car. The vertical force to the wheel is adjustable. The tire-roller contact simulates the real tire-road contact. The roller’s circumferential velocity represents the longitudinal vehicle velocity. The design and analysis of the proposed bench are described in detail. For the developed prototype, the rated clamping force of the electromechanical brake is 11 kN, the maximum vertical force to the wheel reaches 300 kg, and the maximum roller (vehicle) velocity reaches 100 km/h. The measurable bandwidth of the wheel speed is 4 Hz–2 kHz and the motor speed is 2.5 Hz–50 kHz. The measured results including the roller (vehicle) velocity, the wheel velocity, and the wheel slip are satisfactory. This article offers the effective tools to verify all-electric ABS algorithms in a laboratory, hence saving time and cost for the subsequent test on a real road.

No-tillage furrow opener performance: a review of tool geometry, settings and interactions with soil and crop residue

Soil Research ◽  
2020 ◽  
Vol 58 (7) ◽  
pp. 603
Author(s):  
Kojo Atta Aikins ◽  
James B. Barr ◽  
Mustafa Ucgul ◽  
Troy A. Jensen ◽  
Diogenes L. Antille ◽  
...  
Keyword(s):  
Rake Angle ◽  
Soil Disturbance ◽  
Future Research ◽  
Tool Geometry ◽  
Vertical Force ◽  
No Tillage ◽  
Subsurface Soil ◽  
Furrow Opener ◽  
Seed Placement ◽  
Depth Increase

The primary features of an effective and efficient furrow opener include controlled soil disturbance and low draught and vertical force requirements. When integrated in a no-tillage seeding system, furrow openers should also have the ability to assist, and not hinder, the functions of seeding system components – such as maintaining adequate surface residue distribution, accurate and uniform placement of seeds and fertiliser, and regular inter-plant spacing. This review highlights how these goals are affected by opener type, geometry and settings, and soil and residue conditions. Typically, tine openers cause greater soil disturbance than disc openers whereas disc openers are likely to cause residue hairpinning. Winged tine openers reduce residue interference with seed placement and support greater lateral seed spread. Inverted-T openers can achieve subsurface soil shattering, which helps conserve moisture and provides good seed–soil contact. A tine opener with concave cutting edge reduces soil disturbance relative to straight and convex cutting edges. Increasing rake angle, tine width and operating depth increase degree of soil disturbance and draught requirement. Increasing forward speed reduces residue interference with sowing but might decrease the accuracy and uniformity of depth and separation of seed and fertiliser placement. Relative to common openers, bentleg openers have lower draught and penetration force requirements while combining minimal lateral soil throw with high furrow backfill, even at speeds of up to 16 km h–1. The performance of bentleg openers need to be evaluated under residue conditions and in cohesive and adhesive soils. Recommendations for future research are presented.

scholarly journals Ontogeny of aerial righting and wing flapping in juvenile birds

2014 ◽  
Vol 10 (8) ◽  
pp. 20140497 ◽  
Author(s):  
Dennis Evangelista ◽  
Sharlene Cam ◽  
Tony Huynh ◽  
Igor Krivitskiy ◽  
Robert Dudley
Keyword(s):  
Force Production ◽  
Vertical Force ◽  
Alectoris Chukar ◽  
Avian Flight ◽  
Body Roll ◽  
Chukar Partridge

Mechanisms of aerial righting in juvenile chukar partridge ( Alectoris chukar ) were studied from hatching to 14 days-post-hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose-down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e. wing-assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development and are potentially relevant to understanding the origins of avian flight.

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