scholarly journals Experimental Modal Analysis of Hand–Arm Vibration in Golf: Influence of Grip Strength

2019 ◽  
Vol 9 (10) ◽  
pp. 2050 ◽  
Author(s):  
Xavier Chiementin ◽  
Georges Kouroussis ◽  
Sébastien Murer ◽  
Roger Serra
Keyword(s):  
Numerical Model ◽  
Boundary Conditions ◽  
Grip Strength ◽  
Significant Influence ◽  
Scientific Community ◽  
Golf Club ◽  
Modal Characteristics ◽  
Link Performance ◽  
Ball Contact ◽  
Machine Interaction

Interest in the design of products that link performance and comfort is rapidly growing in the field of sport. To this end, the equipment industry is progressively shifting towards customization and it is focusing on man-machine interaction. The notion itself remains insufficiently studied by the scientific community. With regard to golf, several works conclude that vibrations that are perceived in the handle may be harmful and they have significant influence on comfort as well as performance. In that respect, the present paper investigates the effects of grip strength on three indicators of club dynamics: modal characteristics, overall vibratory levels, and vibration dose perceived by the club user, according to ISO 5349 standard. The study can be broken down into three steps. First, the experimental modal characteristics of a golf club are identified while using free-free, fixed-free, and grip-free (with three levels of grip strength) boundary conditions. Subsequently, a numerical model is developed and updated using experimental results. Finally, the root mean squared values and vibration dose transmitted to the hand-arm system after ball contact are extracted from the validated numerical model.

Physical statement of the problem for a numerical model of soil freezing and heaving taking into account heat and mass transfer

2021 ◽  
pp. 244-256
Author(s):  
Виктор Григорьевич Чеверев ◽  
Евгений Викторович Сафронов ◽  
Алексей Александрович Коротков ◽  
Александр Сергеевич Чернятин
Keyword(s):  
Finite Element Method ◽  
Mass Transfer ◽  
Finite Element ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Heat And Mass Transfer ◽  
Soil Freezing ◽  
The Finite Element Method ◽  
Freezing Front ◽  
Element Method

Существуют два основных подхода решения задачи тепломассопереноса при численном моделировании промерзания грунтов: 1) решение методом конечных разностей с учетом граничных условий (границей, например, является фронт промерзания); 2) решение методом конечных элементов без учета границ модели. Оба подхода имеют существенные недостатки, что оставляет проблему решения задачи для численной модели промерзания грунтов острой и актуальной. В данной работе представлена физическая постановка промерзания, которая позволяет создать численную модель, базирующуюся на решении методом конечных элементов, но при этом отражающую ход фронта промерзания - то есть модель, в которой объединены оба подхода к решению задачи промерзания грунтов. Для подтверждения корректности модели был проделан ряд экспериментов по физическому моделированию промерзания модельного грунта и выполнен сравнительный анализ полученных экспериментальных данных и результатов расчетов на базе представленной численной модели с такими же граничными условиями, как в экспериментах. There are two basic approaches to solving the problem of heat and mass transfer in the numerical modeling of soil freezing: 1) using the finite difference method taking into account boundary conditions (the boundary, for example, is the freezing front); 2) using the finite element method without consideration of model boundaries. Both approaches have significant drawbacks, which leaves the issue of solving the problem for the numerical model of soil freezing acute and up-to-date. This article provides the physical setting of freezing that allows us to create a numerical model based on the solution by the finite element method, but at the same time reflecting the route of the freezing front, i.e. the model that combines both approaches to solving the problem of soil freezing. In order to confirm the correctness of the model, a number of experiments on physical modeling of model soil freezing have been performed, and a comparative analysis of the experimental data obtained and the calculation results based on the provided numerical model with the same boundary conditions as in the experiments was performed.

scholarly journals Edge Cooling of a Fuel Cell during Aerial Missions by Ambient Air

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1432
Author(s):  
Lev Zakhvatkin ◽  
Alex Schechter ◽  
Eilam Buri ◽  
Idit Avrahami
Keyword(s):  
Fuel Cell ◽  
Numerical Model ◽  
Wind Tunnel ◽  
Boundary Conditions ◽  
Air Temperature ◽  
Numerical Models ◽  
Heat Removal ◽  
Ambient Air ◽  
Experimental Setup ◽  
Good Agreement

During aerial missions of fuel-cell (FC) powered drones, the option of FC edge cooling may improve FC performance and durability. Here we describe an edge cooling approach for fixed-wing FC-powered drones by removing FC heat using the ambient air during flight. A set of experiments in a wind tunnel and numerical simulations were performed to examine the efficiency of FC edge cooling at various flight altitudes and cruise speeds. The experiments were used to validate the numerical model and prove the feasibility of the proposed method. The first simulation duplicated the geometry of the experimental setup and boundary conditions. The calculated temperatures of the stack were in good agreement with those of the experiments (within ±2 °C error). After validation, numerical models of a drone’s fuselage in ambient air with different radiator locations and at different flight speeds (10–30 m/s) and altitudes (up to 5 km) were examined. It was concluded that onboard FC edge cooling by ambient air may be applicable for velocities higher than 10 m/s. Despite the low pressure, density, and Cp of air at high altitudes, heat removal is significantly increased with altitude at all power and velocity conditions due to lower air temperature.

scholarly journals Experimental study of the impact response of geocells as components of rockfall protection embankments

2009 ◽  
Vol 9 (2) ◽  
pp. 459-467 ◽  
Author(s):  
S. Lambert ◽  
P. Gotteland ◽  
F. Nicot
Keyword(s):  
Experimental Study ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Composite Structures ◽  
Impact Force ◽  
Impact Response ◽  
Rigid Base ◽  
Transmitted Force ◽  
The Impact ◽  
Rockfall Protection

Abstract. Rockfall protection embankments are ground levees designed to stop falling boulders. This paper investigates the behaviour of geocells to be used as components of these structures. Geocells, or cellular confinement systems, are composite structures associating a manufactured envelope with a granular geomaterial. Single cubic geocells were subjected to the impact resulting from dropping a spherical boulder. The geocells were filled with fine or coarse materials and different boundary conditions were applied on the lateral faces. The response is analysed in terms of the impact force and the force transmitted by the geocell to its rigid base. The influence on the geocell response of both the fill material and the cell boundary conditions is analysed. The aim was to identify the conditions resulting in greatest reduction of the transmitted force and also to provide data for the validation of a specific numerical model.

Development of One Dimensional Numerical Model on Large Water Diversion System

2015 ◽  
Vol 744-746 ◽  
pp. 1062-1065
Author(s):  
Cheng Zhang ◽  
Lin Zha
Keyword(s):  
Numerical Model ◽  
Boundary Conditions ◽  
Water Level ◽  
Large Scale ◽  
Water Diversion ◽  
One Dimensional ◽  
Continuous Simulation ◽  
North Water ◽  
Flow Transitions ◽  
Parallel Connections

A one-dimensional numerical model was developed for unsteady-flow in a large-scale conveyance channel with complex inner boundary conditions. Using Taylor expansion and finite difference method, this model incorporated three types of inner boundary conditions, including regulators, inverted siphons, and flumes with parallel connections. It can facilitate continuous simulation with large-amplitude variations in water level and flow discharge during the flow transitions. Transition flows were simulated by this model, which were caused by the operation of a single gate of the Middle Route of the South-to-North Water Diversion Project. The discharges of simulation were consistent with the discharges of formulas calculation, and the water level variations accords with hydraulic law. The results indicate its efficiency and applicability on simulating hydraulic response of large-scale conveyance channels with complex inner boundary conditions.

scholarly journals On the Relationship between Experimental and Numerical Modelling of Gravel-Bed Channel Aggradation

Hydrology ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Barbara Zanchi ◽  
Matteo Zucchi ◽  
Alessio Radice
Keyword(s):  
Numerical Model ◽  
Numerical Modelling ◽  
Boundary Conditions ◽  
Flow Regime ◽  
Model Calibration ◽  
Water Regime ◽  
Morphological Changes ◽  
Regime Changes ◽  
Laboratory Flume ◽  
The Relationship

This communication explores the use of numerical modelling to simulate the hydro-morphologic response of a laboratory flume subject to sediment overloading. The numerical model calibration was performed by introducing a multiplicative factor in the Meyer–Peter and Müller transport formula, in order to achieve a correspondence with the bed and water profiles recorded during a test carried out under a subcritical flow regime. The model was validated using a second subcritical test, and then run to simulate an experiment during which morphological changes made the water regime switch from subcritical to supercritical. The “relationship” between physical and numerical modelling was explored in terms of how the boundary conditions for the two approaches had to be set. Results showed that, even though the first two experiments were reproduced well, the third one could not be modeled adequately. This was explained considering that, after the switch of the flow regime, some of the boundary conditions posed into the numerical model turned out to be misplaced, while others were lacking. The numerical modelling of hydro-morphologic processes where the flow regime is trans-critical in time requires particular care in the position of the boundary conditions, accounting for the instant at which the water regime changes.

scholarly journals Comparison of Experimentally Measured Deformation of the Plate on the Subsoil and the Results of 3D Numerical Model

2014 ◽  
Vol 14 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Jana Labudková ◽  
Radim Čajka
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Parametric Study ◽  
3D Model ◽  
3D Elements ◽  
Final Deformation ◽  
Measured Deformation ◽  
3D Numerical Model

Abstract The purpose of this paper is to compare the measured subsidence of the foundation in experiments and subsidence obtained from FEM calculations. When using 3D elements for creation of a 3D model, it is, in particular, essential to choose correctly the size of the modelled area which represents the subsoil, the boundary conditions and the size of the finite element network. The parametric study evaluates impacts of those parameters on final deformation. The parametric study is conducted of 168 variant models.

Investigating the grip forces exerted by individuals with and without hand arthritis while swinging a golf club with the use of a new wearable sensor technology

2020 ◽  
Vol 234 (3) ◽  
pp. 205-216
Author(s):  
Sara Holland ◽  
James Dickey ◽  
Louis Ferreira ◽  
Emily Lalone
Keyword(s):  
Range Of Motion ◽  
Grip Strength ◽  
Healthy Lifestyle ◽  
Ring Finger ◽  
Movement Analysis ◽  
Sensor Technology ◽  
Configuration Model ◽  
Golf Club ◽  
Significant Deficit ◽  
Impact Sport

Hand arthritis is the leading cause of disability in individuals over the age of 50, causing impairments in grip strength and range of motion. Golf is often recommended to patients with hand arthritis as a low-impact sport to maintain a healthy lifestyle. As such, numerous “arthritic” golf grips have been marketed, but lack quantitative measures to justify their use. The objective of this study was to quantify the differences in total applied grip force in golfers with/without hand arthritis using several types of golf grips. Twenty-seven participants (17 without and 10 with hand arthritis) were evaluated swinging mid-iron clubs with 12 different golf grip designs (9 standard and 3 “arthritic”). The trail hand thumb, index, middle, and ring finger applied grip forces were measured using the wireless FingerTPS system. Finger grip configuration (finger joint angles) of the thumb and index were measured using the Dartfish Movement Analysis Software paired with the newly developed Grip Configuration Model to obtain grip range of motion. Results indicated that golfers with hand arthritis had a significant deficit of 45% golf grip strength (P = 0.02). In addition, individuals with hand arthritis exhibited larger forces in 11 out of 12 golf grips tested when compared with their maximum golf grip strength. Despite how these grips are marketed, there are no “savings” in finger force or grip configuration when using the “arthritic” designed golf grips. Therefore, these grips may not be beneficial for patients with hand arthritis.

scholarly journals Effect of Clearances in Mill Stands on Strip End Motion During Finishing Rolling

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 727 ◽  
Author(s):  
Han-Kai Hsu ◽  
Jong-Ning Aoh
Keyword(s):  
Numerical Model ◽  
Significant Influence ◽  
Work Roll ◽  
Numerical Results ◽  
Maintenance Strategy ◽  
Process Stability ◽  
Finishing Mill ◽  
Clearance Level ◽  
Work Rolls ◽  
Simultaneous Degradation

The process stability of finishing mill is significantly influenced by the clearance between the chocks and housing in mill stands. The on-site data of a finishing mill had shown that the clearances in the finishing mill stands were clearly associated with the incidence of strip end flip. The aim of this work was to establish a numerical model to analyze the effect of the clearances on the deviation of the centerline of the strip and on the incidence of strip end flip. By adopting conditions from a particular strip, the numerical model not only predicted the strip end shape, but also visualized strip end flip, which would be otherwise invisible. Four different degrees of asymmetry regarding work rolls and backup rolls were postulated. It was found that the degradation of the work rolls’ clearance level was the most significant influence on the centerline deviation of the strip. Strip end flip was most susceptible to the degradation of the horizontal clearance of the work roll. The simultaneous degradation of the work rolls’ and backup rolls’ level of clearance led to larger reactions and enhanced the asymmetric wear on the liners. The superimposed axial clearances at the roll end provided an axial constraint to the work roll, and were able to reverse the trend of centerline deviation. The numerical results provided a guideline for designing a suitable maintenance strategy for clearances.

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