scholarly journals Axial rotation as a cause of loss of interference in a shrink fitted split disc assembly

2021 ◽  
pp. 19-32
Author(s):  
Анатолий Александрович Буренин ◽  
Анастасия Валерьевна Ткачева
Keyword(s):  
Angular Velocity ◽  
Axial Rotation ◽  
Thermomechanical Properties ◽  
Operating Conditions ◽  
Relative Rotation ◽  
Centrifugal Forces ◽  
Interference Fit ◽  
Final Structure ◽  
Angular Velocities ◽  
Composite Disk

На примере составного диска, созданного посредством операции горячей посадки, изучается прочность такого соединения на отрыв. Отрывные усилия создаются в качестве центробежных инерционных сил при вращении диска относительное его центральной оси. Показывается, что созданный натяг в сборке имеет выраженную тенденцию к уменьшению. Однако для его обнуления необходимы достаточно значительные угловые скорости вращения. Приведен пример расчета придельной угловой скорости в зависимости от первоначального нагрева охватывающей детали сборки, термомеханических свойств материала сборки и геометрических параметров итоговой конструкции. Подобные расчеты в снижающемся натяге совершенно необходимы, когда эксплуатационные условия требуют принять вращение составного диска в качестве части его функциональных обязанностей. On the example of a composite disk, created by means of a hot-fit operation, the pulloff strength of such a disk is studied. separation forces as centrifugal forces with relative rotation of its central axis. It is shown that the created interference fit in the assembly has a pronounced tendency to decrease. However, for vanishing, sufficiently significant angular velocities of rotation are required. An example of calculating the near-limit angular velocity, depending on the original covered part of the assembly, of the thermomechanical properties of the material and the geometric characteristics of the final structure is given. Such computations in decreasing interference are essential when operating conditions require the rotation of the composite disc to be accepted as part of its functionality.

scholarly journals Study on Design of Non-Circular Gears for Speed Control of the Squid Belly Opening and Gutting Machine (SBOGM)

2021 ◽  
Vol 11 (7) ◽  
pp. 3268
Author(s):  
Hyo-Seong Jang ◽  
Chang-Hyun Lee ◽  
Gun-Young Park ◽  
Chul Kim
Keyword(s):  
Angular Velocity ◽  
Velocity Ratio ◽  
Operating Conditions ◽  
Structural Safety ◽  
Spur Gears ◽  
Operating Environments ◽  
Complex Design ◽  
Angular Velocities ◽  
Rotational Motions ◽  
Precise Expression

Non-circular gears can maintain rotational motions of general gears and implement all varying rotational motions of the cam. They adjust the angular velocity of driven gear according to operating conditions and make precise changes in angular motion. The design of non-circular gears has not been sufficiently studied because of their particularity and complex design methods unlike spur gears. In the gutting section of the Squid Belly Opening and Gutting Machine (SBOGM), spur gears generate rotational impact due to constant angular velocities, causing noise and equipment damage; so, efficiency should be improved by varying sectional angular velocity. Therefore, we derived pitch curves by selecting angular velocity ratio considering operating environments, and the tooth profile was designed by calculating module for each section according to radius through theorical analysis for precise expression of angular velocity ratio. To confirm reliability of design, angular velocity ratio and structural safety of designed non-circular gears were verified using, commercial software, ‘DAFUL 2020 R1′.

scholarly journals Three-Dimensional Upper Body Kinematics and Inter-articular Kinematic Sequence During a Canoe Polo Throw

2021 ◽  
Vol 3 ◽  
Author(s):  
Najoua Assila ◽  
Cyril Delavallade ◽  
Yoann Blache ◽  
Christian Berger-Vachon ◽  
Philippe Collotte ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Inverse Kinematics ◽  
Three Dimensional ◽  
Statistical Parametric Mapping ◽  
Vertical Axis ◽  
Axial Rotation ◽  
Upper Body ◽  
Parametric Mapping ◽  
Overhead Sports ◽  
Angular Velocities

Canoe polo is an increasingly popular discipline requiring both kayaking and ball-handling skills. While the kinematics of the upper body during throw has been investigated for several overhead sports, the canoe polo throw has still to be studied. Therefore, the aim of this study is to analyze the canoe polo throw kinematics in terms of angles and inter-articular sequencing to understand its specificity. A secondary aim was to investigate whether adding pelvis mobility has an impact. Nineteen male players of canoe polo were equipped with reflective body markers for the throw analysis. They performed 5 throws with the pelvis fixed and 5 throws with additional pelvic mobility in rotation around a vertical axis. Inverse kinematics was performed with OpenSim providing pelvis, trunk, and glenohumeral rotations. Angular velocities were calculated to build the inter-articular sequences relative to these throws. Statistical parametric mapping was used to assess the effect of pelvis mobility on the throwing kinematics. Similar kinematics patterns as in other overhead sports were observed, however, a different inter-articular sequence was found for the canoe polo throw with a maximal angular velocity occurring sooner for the thorax in axial rotation than for the pelvis in rotation. While the limitation of rotation of the pelvis around a vertical axis has an influence on the pelvis and trunk kinematics, it did not modify the kinematic sequence.

Differences in Human Cervical Spine Kinematics for Active and Passive Motions of Symptomatic and Asymptomatic Subject Groups

2013 ◽  
Vol 29 (5) ◽  
pp. 543-553 ◽  
Author(s):  
Brad Rutledge ◽  
Tamara Reid Bush ◽  
Joseph Vorro ◽  
Mingfei Li ◽  
Lisa DeStefano ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Imaging Techniques ◽  
Axial Rotation ◽  
Lateral Flexion ◽  
Asymptomatic Group ◽  
Group Assignment ◽  
Objective Standard ◽  
Angular Velocities ◽  
Kinematic Measures ◽  
Asymptomatic Subjects

Most musculoskeletal disorders of the head and neck regions cannot be identified through imaging techniques; therefore clinician-conducted assessments (passive motions) are used to evaluate the functional ability of these regions. Although active motions do not require interaction with a clinician, these movements can also provide diagnostic indicators of dysfunction. The purpose of this research was to determine whether kinematic measures differed between active and passive movements of participants in symptomatic and asymptomatic groups. Data obtained on cervical lateral flexion range of motion (ROM), coupled axial rotation, and the angular velocity of lateral flexion were statistically analyzed and demonstrated differences between active and passive motions for symptomatic and asymptomatic subjects. Active motions had higher angular velocities (P< .001) and larger ROMs, with greater lateral flexions (P< .05). The asymptomatic group produced a larger average lateral flexion of 7.9° at an average angular velocity of 2 deg/s greater than the symptomatic group. Trends with regard to group assignment were the same for active and passive motions. This work demonstrates the potential for using kinematic measures of active and passive motions to develop an objective standard for diagnoses of cervical dysfunction and supports validity of the clinician-based analysis to distinguish between participant groups.

The Analysis of Proprioception Alteration during First Five Months after Anterior Cruciate Ligament Reconstruction

2018 ◽  
Vol 1 (84) ◽  
Author(s):  
Vilma Jurevičienė ◽  
Albertas Skurvydas ◽  
Juozas Belickas ◽  
Giedra Bušmanienė ◽  
Dovilė Kielė ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Angular Velocity ◽  
Knee Joint ◽  
Cruciate Ligament ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Starting Position ◽  
Angular Velocities ◽  
Anterior Cruciate

Research  background  and  hypothesis.  Proprioception  is  important  in  the  prevention  of  injuries  as  reduced proprioception  is  one  of  the  factors  contributing  to  injury  in  the  knee  joint,  particularly  the  ACL.  Therefore, proprioception appears not only important for the prevention of ACL injuries, but also for regaining full function after ACL reconstruction.Research aim. The aim of this study was to understand how proprioception is recovered four and five months after anterior cruciate ligament (ACL) reconstruction.Research methods. The study included 15 male subjects (age – 33.7 ± 2.49 years) who had undergone unilateral ACL reconstruction with a semitendinosus/gracilis (STG) graft in Kaunas Clinical Hospital. For proprioceptive assessment, joint position sense (JPS) was measured on both legs using an isokinetic dynamometer (Biodex), at knee flexion of 60° and 70°, and at different knee angular velocities of 2°/s and 10°/s. The patients were assessed preoperatively and after 4 and 5 months, postoperatively.Research results. Our study has shown that the JPS’s (joint position sense) error scores  to a controlled active movement is significantly higher in injured ACL-deficient knee than in the contralateral knee (normal knee) before surgery and after four and five months of rehabilitation.  After 4 and 5 months of rehabilitation we found significantly lower values in injured knees compared to the preoperative data. Our study has shown that in injured knee active angle reproduction errors after 4 and 5 months of rehabilitation were higher compared with the ones of the uninjured knee. Proprioceptive ability on the both legs was  independent of all differences angles for target and starting position for movement. The knee joint position sense on both legs depends upon the rate of two different angular velocities and the mean active angle reproduction errors at the test of angular velocity slow speed was the highest compared with the fast angular velocity. Discussion and conclusions. In conclusion, our study shows that there was improvement in mean JPS 4 and 5 months after ACL reconstruction, but it did not return to normal indices.Keywords: knee joint, joint position sense, angular velocity, starting position for movement.

Finite difference code for velocity and surface traction of a Fluid between Two Eccentric Spheres

2015 ◽  
Vol 11 (1) ◽  
pp. 2960-2971
Author(s):  
M.Abdel Wahab
Keyword(s):  
Velocity Field ◽  
Angular Velocity ◽  
Finite Difference ◽  
Numerical Study ◽  
Outer Sphere ◽  
Equation Of Motion ◽  
Annular Region ◽  
Surface Traction ◽  
Angular Velocities ◽  
Axis Passing

The Numerical study of the flow of a fluid in the annular region between two eccentric sphere susing PHP Code isinvestigated. This flow is created by considering the inner sphere to rotate with angular velocity 1  and the outer sphererotate with angular velocity 2  about the axis passing through their centers, the z-axis, using the three dimensionalBispherical coordinates (, ,) .The velocity field of fluid is determined by solving equation of motion using PHP Codeat different cases of angular velocities of inner and outer sphere. Also Finite difference code is used to calculate surfacetractions at outer sphere.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

Scission and Healing in a Spinning Elastomeric Cylinder at Elevated Temperature

2002 ◽  
Vol 69 (5) ◽  
pp. 602-609 ◽  
Author(s):  
A. S. Wineman ◽  
J. A. Shaw
Keyword(s):  
Elevated Temperature ◽  
Angular Velocity ◽  
Critical Value ◽  
Anomalous Behavior ◽  
Molecular Networks ◽  
Material System ◽  
Elastomeric Material ◽  
Angular Velocities ◽  
Macromolecular Network ◽  
Temperature Responses

When an elastomeric material is subject to sufficiently high temperature, macromolecular network junctions can undergo time-dependent scission and re-crosslinking (healing). The material system then consists of molecular networks with different reference states. A constitutive framework, based on the experimental work of Tobolsky, is used to determine the evolution of deformation of a solid rubber cylinder spinning at constant angular velocity at an elevated temperature. Responses based on underlying neo-Hookean, Mooney-Rivlin, and Arruda-Boyce models, were solved numerically and compared. Different amounts of healing were studied for each case. For neo-Hookean molecular networks, there may be a critical finite time when the radius grows infinitely fast and the cylinder “blows up.” This time depends on the angular velocity and the rate of re-cross linking. In addition, no solution was possible for angular velocities above a critical value, even without the effects of scission. Such anomalous behavior does not occur for Mooney-Rivlin or Arruda-Boyce network response.

Muscle function during jumping in frogs. I. Sarcomere length change, EMG pattern, and jumping performance

1996 ◽  
Vol 271 (2) ◽  
pp. C563-C570 ◽  
Author(s):  
G. J. Lutz ◽  
L. C. Rome
Keyword(s):  
Mechanical Properties ◽  
Muscle Function ◽  
Length Change ◽  
Operating Conditions ◽  
Mechanical Power ◽  
Shortening Velocity ◽  
Jumping Performance ◽  
Angular Velocities ◽  
High Level

We determined the influence of temperature on muscle function during jumping to better understand how the frog muscular system is designed to generate a high level of mechanical power. Maximal jumping performance and the in vivo operating conditions of the semimembranosus muscle (SM), a hip extensor, were measured and related to the mechanical properties of the isolated SM in the accompanying paper [Muscle function during jumping in frogs. II. Mechanical properties of muscle: implication for system design. Am. J. Physiol. 271 (Cell Physiol. 40): C571-C578, 1996]. Reducing temperature from 25 to 15 degrees C caused a 1.75-fold decline in peak mechanical power generation and a proportional decline in aerial jump distance. The hip and knee joint excursions were nearly the same at both temperatures. Accordingly, sarcomeres shortened over the same range (2.4 to 1.9 microns) at both temperatures, corresponding to myofilament overlap at least 90% of maximal. At the low temperature, however, movements were made more slowly. Angular velocities were 1.2- to 1.4-fold lower, and ground contact time was increased by 1.33-fold at 15 degrees C. Average shortening velocity of the SM was only 1.2-fold lower at 15 degrees C than at 25 degrees C. The low Q10 of velocity is in agreement with that predicted for muscles shortening against an inertial load.

Experimental Exploration of Schallamach Waves and Self-Excitation in a Belt-Drive System

2018 ◽  
Author(s):  
Yingdan Wu ◽  
Michael Varenberg ◽  
Michael J. Leamy
Keyword(s):  
Angular Velocity ◽  
Dynamic Behavior ◽  
Oscillation Amplitude ◽  
Operating Conditions ◽  
Drive System ◽  
Belt Drive ◽  
Stick Slip ◽  
Stick Slip Motion ◽  
System Inertia ◽  
Slip Motion

We study the dynamic behavior of a belt-drive system to explore the effect of operating conditions and system moment of inertia on the generation of waves of detachment (i.e., Schallamach waves) at the belt-pulley interface. A self-excitation phenomenon is reported in which frictional fluctuations serve as harmonic forcing of the pulley, leading to angular velocity oscillations which grow in time. This behavior depends strongly on operating conditions (torque transmitted and pulley speed) and system inertia, and differs between the driver and driven pulleys. A larger net torque applied to the pulley generally yields more remarkable stick-slip oscillations with higher amplitude and lower frequency. Higher driving speeds accelerate the occurrence of stick-slip motion, but have little influence on the oscillation amplitude. Contrary to our expectations, the introduction of flywheels to increase system inertia amplified the frictional disturbances, and hence the pulley oscillations. This does, however, suggest a way of facilitating their study, which may be useful in follow-on research.

The Relationship between Consistency of Propulsive Cycles and Maximum Angular Velocity during Wheelchair Racing

2008 ◽  
Vol 24 (3) ◽  
pp. 280-287 ◽  
Author(s):  
Yong “Tai” Wang ◽  
Konstantinos Dino Vrongistinos ◽  
Dali Xu
Keyword(s):  
Angular Velocity ◽  
Upper Limb ◽  
Wheelchair Propulsion ◽  
Upper Arm ◽  
Wheelchair Athletes ◽  
Angular Velocities ◽  
Limb Kinematics ◽  
Analysis System ◽  
The Right ◽  
The Relationship

The purposes of this study were to examine the consistency of wheelchair athletes’ upper-limb kinematics in consecutive propulsive cycles and to investigate the relationship between the maximum angular velocities of the upper arm and forearm and the consistency of the upper-limb kinematical pattern. Eleven elite international wheelchair racers propelled their own chairs on a roller while performing maximum speeds during wheelchair propulsion. A Qualisys motion analysis system was used to film the wheelchair propulsive cycles. Six reflective markers placed on the right shoulder, elbow, wrist joints, metacarpal, wheel axis, and wheel were automatically digitized. The deviations in cycle time, upper-arm and forearm angles, and angular velocities among these propulsive cycles were analyzed. The results demonstrated that in the consecutive cycles of wheelchair propulsion the increased maximum angular velocity may lead to increased variability in the upper-limb angular kinematics. It is speculated that this increased variability may be important for the distribution of load on different upper-extremity muscles to avoid the fatigue during wheelchair racing.

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