scholarly journals Impact testing of snowboarding wrist protectors

2021 ◽  
pp. 175433712110547
Author(s):  
Caroline Adams ◽  
Tom Allen ◽  
Terry Senior ◽  
David James ◽  
Nick Hamilton
Keyword(s):  
Injury Risk ◽  
Impact Force ◽  
Impact Testing ◽  
Finite Element Models ◽  
Vertical Force ◽  
Test Device ◽  
Wrist Extension ◽  
Impact Forces ◽  
Pendulum Test ◽  
The Impact

The wrist is a common injury site for snowboarders who often fall onto an outstretched hand. Wrist protectors are worn by some snowboarders to prevent wrist injuries by attenuating impact forces and limiting wrist extension. This paper presents a bespoke pendulum test device for impacting wrist protectors when fitted to a wrist surrogate. The rig can replicate injury risk scenarios, while measuring temporal forces and wrist extension angles. Results from testing 12 snowboarding wrist protectors are presented, including differences in peak vertical force, the time to reach this peak, and energy absorption between products. When compared to an unprotected surrogate, all 12 products lowered the peak force by at least 24% and increased the time to reach this peak by at least 1.8 times. Due to the severity of the load case employed, none of the products lowered the impact force below 2.8 kN, which is the value presented in the literature to fracture a cadaveric wrist. The developed rig could be used to support the development of new wrist protectors, as well as the development of finite element models for predicting wrist protector performance.

scholarly journals Unique method for analysing pressure distribution accross the knuckles during boxing

2015 ◽  
Author(s):  
Mike Loosemore ◽  
Joseph Lightfoot ◽  
Jay Meswania ◽  
Chris Beardsley
Keyword(s):  
Injury Risk ◽  
Impact Force ◽  
Reliability And Validity ◽  
Distribution Patterns ◽  
Stationary Target ◽  
Impact Forces ◽  
Within Subjects ◽  
The Individual ◽  
The Impact ◽  
Proportional Distribution

Objectives: The hand is commonly injured in boxing but it is not clear why some athletes sustain hand injuries while others do not. It is possible that there are differences in the distribution of impact forces at the knuckle during punching between athletes and that certain distribution patterns may be predictive of increased injury risk. We developed a method of analysing the distribution of impact forces at the knuckle during punching using pressure film. Pressure film allows a calculation of the distribution and magnitude of pressure and force between any two surfaces that come into contact. Methods: Pressure film was inserted into the gloves of three male subjects prior to punching a stationary target. After each punch, the pressure film was removed and analysed to determine the distribution of the impact force during each punch across each of the four knuckles. Punches were repeated multiple times for each subject. The proportional distribution of the impact force during punches was compared between knuckles and within subjects. Results: The proportional distribution of the impact force exerted during punches was significantly different between knuckles and within subjects (p < 0.05). Knuckle 2 displayed the largest proportion of impact forces while knuckle 3 displayed the smallest proportion of impact forces. Conclusions: Pressure film inserted into boxing gloves can be used to analyse the distribution of impact forces across the knuckles during punching. Further work is needed to confirm the reliability and validity of the technique and establish whether there is an association between the impact forces at the individual knuckles and hand injury risk during boxing.

Effect of Upper and Lower Extremity Control Strategies on Predicted Injury Risk During Simulated Forward Falls: A Study in Healthy Young Adults

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
JiaHsuan Lo ◽  
James A. Ashton-Miller
Keyword(s):  
Kinetic Energy ◽  
Injury Risk ◽  
Impact Force ◽  
The Body ◽  
Whole Body ◽  
Joint Control ◽  
Negative Work ◽  
Impact Forces ◽  
Hip Flexion ◽  
The Impact

Fall-related wrist fractures are common at any age. We used a seven-link, sagittally symmetric, biomechanical model to test the hypothesis that systematically alterations in the configuration of the body during a forward fall from standing height can significantly influence the impact force on the wrists. Movement of each joint was accomplished by a pair of agonist and antagonist joint muscle torque actuators with assigned torque-angle, torque-velocity, and neuromuscular latency properties. Proportional-derivative joint controllers were used to achieve desired target body segment configurations in the pre- and∕or postground contact phases of the fall. Outcome measures included wrist impact forces and whole-body kinetic energy at impact in the best, and worst, case impact injury risk scenarios. The results showed that peak wrist impact force ranged from less than 1kN to more than 2.5kN, reflecting a fourfold difference in whole-body kinetic energy at impact (from less than 40J to more than 160J) over the range of precontact hip and knee joint angles used at impact. A reduction in the whole-body kinetic energy at impact was primarily associated with increasing negative work associated with hip flexion. Altering upper extremity configuration prior to impact significantly reduced the peak wrist impact force by up to 58% (from 919Nto2212N). Increased peak wrist impact forces associated greater shoulder flexion and less elbow flexion. Increasing postcontact arm retraction can reduce the peak wrist impact force by 28% (from 1491Nto1078N), but postcontact hip and knee rotations had a relatively small effect on the peak wrist impact force (8% reduction; from 1411Nto1303N). In summary, the choice of the joint control strategy during a forward fall can significantly affect the risk of wrist injury. The most effective strategy was to increase the negative work during hip flexion in order to dissipate kinetic energy thereby reducing the loss in potential energy prior to first impact. Extended hip or elbow configurations should be avoided in order to reduce forearm impact forces.

scholarly journals Unique method for analysing pressure distribution accross the knuckles during boxing

2015 ◽  
Author(s):  
Mike Loosemore ◽  
Joseph Lightfoot ◽  
Jay Meswania ◽  
Chris Beardsley
Keyword(s):  
Injury Risk ◽  
Impact Force ◽  
Reliability And Validity ◽  
Distribution Patterns ◽  
Stationary Target ◽  
Impact Forces ◽  
Within Subjects ◽  
The Individual ◽  
The Impact ◽  
Proportional Distribution

Objectives: The hand is commonly injured in boxing but it is not clear why some athletes sustain hand injuries while others do not. It is possible that there are differences in the distribution of impact forces at the knuckle during punching between athletes and that certain distribution patterns may be predictive of increased injury risk. We developed a method of analysing the distribution of impact forces at the knuckle during punching using pressure film. Pressure film allows a calculation of the distribution and magnitude of pressure and force between any two surfaces that come into contact. Methods: Pressure film was inserted into the gloves of three male subjects prior to punching a stationary target. After each punch, the pressure film was removed and analysed to determine the distribution of the impact force during each punch across each of the four knuckles. Punches were repeated multiple times for each subject. The proportional distribution of the impact force during punches was compared between knuckles and within subjects. Results: The proportional distribution of the impact force exerted during punches was significantly different between knuckles and within subjects (p < 0.05). Knuckle 2 displayed the largest proportion of impact forces while knuckle 3 displayed the smallest proportion of impact forces. Conclusions: Pressure film inserted into boxing gloves can be used to analyse the distribution of impact forces across the knuckles during punching. Further work is needed to confirm the reliability and validity of the technique and establish whether there is an association between the impact forces at the individual knuckles and hand injury risk during boxing.

The Effects of Upstream Flexible Barrier on the Debris Flow Entrainment and Impact Dynamics on a Terminal Barrier

2021 ◽  
Author(s):  
Hervé Vicari ◽  
C.W.W. Ng ◽  
Steinar Nordal ◽  
Vikas Thakur ◽  
W.A. Roanga K. De Silva ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Impact Force ◽  
Dynamic Pressure ◽  
Pressure Coefficient ◽  
Flexible Barrier ◽  
Impact Forces ◽  
Flexible Barriers ◽  
The Impact ◽  
Bed Entrainment

The destructive nature of debris flows is mainly caused by flow bulking from entrainment of an erodible channel bed. To arrest these flows, multiple flexible barriers are commonly installed along the predicted flow path. Despite the importance of an erodible bed, its effects are generally ignored when designing barriers. In this study, three unique experiments were carried out in a 28 m-long flume to investigate the impact of a debris flow on both single and dual flexible barriers installed in a channel with a 6 m-long erodible soil bed. Initial debris volumes of 2.5 m<sup>3</sup> and 6 m<sup>3</sup> were modelled. For the test setting adopted, a small upstream flexible barrier before the erodible bed separates the flow into several surges via overflow. The smaller surges reduce bed entrainment by 70% and impact force on the terminal barrier by 94% compared to the case without an upstream flexible barrier. However, debris overflowing the deformed flexible upstream barrier induces a centrifugal force that results in a dynamic pressure coefficient that is up to 2.2 times higher than those recommended in guidelines. This suggests that although compact upstream flexible barriers can be effective for controlling bed entrainment, they should be carefully designed to withstand higher impact forces.

scholarly journals Comparison of branded rugby headguards on their effectiveness in reducing impact on the head

2018 ◽  
Vol 4 (1) ◽  
pp. e000361 ◽  
Author(s):  
Erin R A Frizzell ◽  
Graham P Arnold ◽  
Weijie Wang ◽  
Rami J Abboud ◽  
Tim S Drew
Keyword(s):  
Impact Force ◽  
Linear Acceleration ◽  
Baseline Measurement ◽  
Peak Acceleration ◽  
Impact Forces ◽  
Impact Attenuation ◽  
The Mean ◽  
Force Reduction ◽  
The Right ◽  
The Impact

AimTo compare the available brands of rugby headguards and evaluate their impact attenuation properties at various locations on the cranium, with regard to concussion prevention.MethodsSeven different branded headguards were fitted onto a rigid headform and drop-tested in three different positions. An accelerometer measured the linear acceleration the headform experienced on impact with the ground. Each test involved dropping the headform from a height that generated 103.8 g on average when bare, which is the closest acceleration to the upper limit of the concussion threshold of 100 g. A mean peak acceleration for each drop position was calculated and compared with the bare baseline measurement.ResultsEach headguard demonstrated a significant decrease in the mean peak acceleration from the baseline value (all p≤0.01). Overall the Canterbury Ventilator was the most effective headguard, decreasing the impact force on average by 47%. The least effective was the XBlades Elite headguard, averaging a force reduction of 27%. In five of the seven headguards, the right side of the headwear was the most effective at reducing impact force.ConclusionOverall, the results indicate that it would be beneficial to wear a headguard during rugby in order to reduce the impact forces involved in head collisions. There was also a clear difference in performance between the tested brands, establishing the Canterbury headguard as the most effective. However, only one model of headguard from each brand was tested, so further research evaluating all other models should be considered.

scholarly journals STUDY ON IMPACT FORCES OF THE UNDERWATER CAVITY PROJECTILE

2016 ◽  
Vol 54 (6) ◽  
pp. 797
Author(s):  
Nguyen Thai Dung ◽  
Nguyen Duc Thuyen
Keyword(s):  
Drag Force ◽  
Impact Force ◽  
Center Of Mass ◽  
Forward Direction ◽  
Cavity Wall ◽  
Impact Point ◽  
Impact Forces ◽  
Underwater Projectile ◽  
The Impact ◽  
Cavity Effect

The motion of the underwater projectile with cavity effect including two motions: the projectile moves in the forward direction, center of mass of the projectile rotation around its nose makes tail of the projectile impacts on the cavity wall. According to, the impact forces occur, they include the drag force at its none, the impact force at impact point. The paper studies the forces occur on during motion of the underwater cavity projectile. Added, this paper considers the effect of the length and distributive projectile to the magnitude of impact force and the drag force of the underwater cavity projectile.

A system for simulating the kinematics and measuring the impact force from riding whips used in Thoroughbred horseracing

2020 ◽  
pp. 175433712098062
Author(s):  
John W Bridge ◽  
Kaleb M Dempsey ◽  
Kayla M Danicki ◽  
Robin L Angotti ◽  
Alan K Kwiatkowski ◽  
...  
Keyword(s):  
Impact Force ◽  
Dynamic Force ◽  
Horse Racing ◽  
Testing Device ◽  
Shaft Length ◽  
Impact Forces ◽  
The Face ◽  
Flap Design ◽  
Arm Motion ◽  
The Impact

Thirty horse racing whips of four different designs were tested to measure dynamic impact force and compared using a specially designed mechanical testing device to simulate the whipping action of a jockey during racing. The whips tested included designs used in Thoroughbred horse racing in North America, which meet the design criteria established by the Association of Racing Commissioners International (ARCI) model rules, as well as the most common whip used in British horse racing. The objective of the device was to allow comparisons to be made between peak impact loads resulting from different whip designs. A high peak dynamic force on a horse’s shoulder or hind quarter may result in injuries, such as welts. The testing device contains a planar three-bar, open mechanical linkage loaded by torsion springs to model the arm motion of a jockey. The whip strikes a flat plate covered by an elastomeric pad. The energy input is replicated during the simulated impact. A single axis dynamic load cell under the loading plate and three single-turn precision potentiometers located at each joint of the three-arm mechanical system measure impact forces and relative angular positions, respectively. Force measurements are compared from the face of each whip and the edge or seam where applicable. In addition to the flap design, other physical differences between whip designs included mass, shaft length, shaft stiffness, flap cushion thickness/compression factor, flap surface area, and flap seam area. Statistically significant impact force differences were found between flap face and flap seam impact orientations, with higher impact forces delivered by the flap face. Significant differences were also found in impact forces between the three whip styles with seams.

scholarly journals Debris Flow Damage Assessment by Considering Debris Flow Direction and Direction Angle of Structure in South Korea

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 328 ◽  
Author(s):  
Dong Nam ◽  
Man-Il Kim ◽  
Dong Kang ◽  
Byung Kim
Keyword(s):  
South Korea ◽  
Debris Flow ◽  
Debris Flows ◽  
Impact Force ◽  
Mountainous Areas ◽  
Mountainous Regions ◽  
Impact Forces ◽  
The Impact

Recently, human and property damages have often occurred due to various reasons—such as landslides, debris flow, and other sediment-related disasters—which are also caused by regional torrential rain resulting from climate change and reckless development of mountainous areas. Debris flows mainly occur in mountainous areas near urban living communities and often cause direct damages. In general, debris flows containing soil, rock fragments, and driftwood temporarily travel down to lower parts along with a mountain torrent. However, debris flows are also often reported to stream down from the point where a slope failure or a landslide occurs in a mountain directly to its lower parts. The impact of those debris flows is one of the main factors that cause serious damage to structures. To mitigate such damage of debris flows, a quantitative assessment of the impact force is thus required. Moreover, technologies to evaluate disaster prevention facilities and structures at disaster-prone regions are needed. This study developed two models to quantitatively analyze the damages caused by debris flows on structures: Type-1 model for calculating the impact force, which reflected the flow characteristics of debris flows and the Type-2 model, which calculated the impact force based on the topographical characteristics of mountainous regions. Using RAMMS a debris flow runoff model, the impact forces assessed through Type-1 and Type-2 models were compared to check reliability. Using the assessed impact forces, the damage ratio of the structures was calculated and the amount of damage caused by debris flows on the structures was ultimately assessed. The results showed that the Type-1 model overestimated the impact force by 10% and the Type-2 model by 4% for Mt. Umyeon in Seoul, compared to the RAMMS model. In addition, the Type-1 model overestimated the impact force by 3% and Type-2 by 2% for Mt. Majeok in Chuncheon, South Korea.

Energy Parameters of the Binder during Activation in the Vortex Layer Apparatus

2019 ◽  
Vol 945 ◽  
pp. 98-103 ◽  
Author(s):  
Ruslan A. Ibragimov ◽  
Evgeniy V. Korolev ◽  
T.R. Deberdeev ◽  
V.V. Leksin ◽  
Denis B. Solovev
Keyword(s):  
Material Science ◽  
Fill Factor ◽  
Impact Force ◽  
Ferromagnetic Particle ◽  
Particle Collision ◽  
Test Device ◽  
Vortex Layer ◽  
The Impact ◽  
Ground Material ◽  
Grinding Time

Improving the efficiency of construction composites is a relevant problem for modern-day material science. One of the ways to solve the problem consists in activating the binders by means of vortex-layer devices. Mathematical transformations produced a formula for calculating the dependency of the number of ferromagnetic-particle collision on the number and velocity of such particles, as well as on the device chamber fill factor. The results obtained by applying the proposed formula differ from D.D. Logvinenko's model by 10% at max. We calculated the impact force, the impulse of the grinding body in the vortex-layer device, as well as the amount of applied energy per unit of mass of the ground material. It was found out that the impact force and the impulse of force were maximized in the test device. At the same time, energy applied over the grinding time necessary to even out the binder dispersion in the vortex-layer device was 2 to 4.8 times greater compared to conventional devices.

scholarly journals Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 347 ◽  
Author(s):  
Seyed Mohammad Khatami ◽  
Hosein Naderpour ◽  
Rui Carneiro Barros ◽  
Anna Jakubczyk-Gałczyńska ◽  
Robert Jankowski
Keyword(s):  
Kinetic Energy ◽  
Impact Force ◽  
Damping Ratio ◽  
Dissipated Energy ◽  
Force Model ◽  
Single Collision ◽  
Structural Pounding ◽  
Impact Forces ◽  
The Impact ◽  
Impact Damping

Structural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various approaches. Firstly, for the case of collisions between two structural elements, the dissipated energy during impact has been compared to the loss of kinetic energy. In the second stage of verifications, the peak impact forces during single collision have been analyzed. Then, the accuracy of different equations have been verified by comparing the impact force time histories for the situation when a concrete ball is dropped on a rigid concrete surface. Finally, pounding between two structures during earthquakes has been studied. The results of the analysis focused on comparison between dissipated and kinetic energy show relatively low errors between calculated and assumed values of the coefficient of restitution when the proposed equation is used. In addition, the results of the comparison between experimentally and numerically determined peak impact forces during single collision confirm the effectiveness of the approach. The same conclusion has been obtained for the whole impact time history for collision between a ball and a rigid surface. Finally, the results of the comparative analysis, conducted for pounding between two structures during an earthquake, confirm the simulation accuracy when the proposed approach is used. The above conclusions indicate that the proposed formula for impact damping ratio, as a parameter of impact force model for simulation of earthquake-induced structural pounding, is very effective and accurate in numerical simulations in the case of different scenarios.

Sign in / Sign up

Export Citation Format

Share Document