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Material properties of golf ball layers 

Material properties of golf ball layers 

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Article
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To model the impact dynamics of a golf drive, finite element (FE) models of the ball and the clubhead are created and combined to simulate the collision of the two bodies. A three-piece golf ball is modelled using only solid elements, while the clubhead is modelled using solid elements for the crucial area of the impact, i.e. the clubface, and usin...

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Citations

... projectile during impact with the ball [14], if the mass used to increase club MOI was located in the shaft, it is expected that a decrease in both clubhead and ball velocity would be observed. Mass has previously been added to the shaft as opposed to the clubhead [15,16]; however, the small magnitude of mass used, and the location of this mass would have had only a small effect on MOI, hence sizeable differences in velocity were not observed. ...
Article
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The moment of inertia of a golf club, quantified about an axis at the butt of the handle, normal to the swing plane, has the potential to influence both clubhead and ball velocity. The purpose of this study was to assess the reliability of clubhead and ball velocity with changes to moment of inertia over repeat testing sessions and, if reliable, to quantify the effect of modifying moment of inertia. Eleven skilled male golfers hit 20 golf shots with three golf clubs, each with a different moment of inertia achieved through adding mass inside the club shaft and repeated this protocol over three sessions. A commercially available launch monitor was used to measure both velocity variables. Test–retest reliability was assessed via (1) limits of agreement, to determine reliability from a change in magnitude perspective and (2) linear-weighted kappa, to determine reliability from a directional perspective. The effect of moment of inertia on clubhead and ball velocity was determined using one-way, repeated measures analysis of variance tests, with partial eta squared being used to quantify the size of the effect. Increasing golf club moment of inertia reliably decreased clubhead and ball velocity, with fair to substantial kappa results revealed between sessions. The magnitude of decrease in these velocities, however, could not be reliably quantified. Statistically, the influence of moment of inertia was considered large (η2 ≥ 0.662 and 0.404) and significant (p < 0.001 and ≤ 0.006) for both clubhead and ball velocity, respectively.
... It can be used to initiate further simulations on different materials, geometries, or hand placements [49]. Cheong et al. [36] conclude that the mechanical performance of the shaft is greatly influenced by the fiber orientation; Petersen and McPhee [50] optimize the club head and increase the speed at impact by 4.8 m/s, resulting in a 20 m longer shot distance. The contact is simulated at the center of the head without taking the modal shape of the shaft into account. ...
... Finally, it has also been demonstrated that vibration feedback is associated to an incorrect hit [28]. A ball might be simulated and studied in order to compute its kinetic energy after being hit, similarly to the finite element simulations that were conducted by Petersen and McPhee [50] on the collision of the ball and club head. ...
Article
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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.
... 7 Hence, the elastic modulus of the core and mid-layer is lower than that of the cover. 8 Besides having a great influence on the energytransfer efficiency, the mechanical properties of the ball also influence the generation of ball spin that is acquired during impact between the club face and the ball. 7,9,10 Initially, the ball will start to slide along the club face, and as the friction between the ball and club face increases, the ball will start to roll. ...
Article
The purpose of this study was to investigate the effect of ball temperature on impact ball speed and carry distance during golf drives in a blind randomized test design. The balls were exposed to a temperature-controlled environment (4 °C, 18 °C, 32 °C, and 46 °C) for 24 h prior to the test and each temperature group consisted of 30 balls. The 120 drives were performed by an elite male golfer (handicap: 0.0) in an indoor driving range. All drives were measured by a Doppler-radar system to determine the club-head speed, launch angle, spin rate, ball speed, and carry distance. Differences between the groups were investigated using a one-way analysis of variance. The results indicated that ball-speed and carry-distance differences occurred within the four groups (p < 0.001 and p < 0.01, respectively). The post hoc analyses showed that the ball temperatures of 18 °C and 32 °C had greater ball speeds and carry distances than balls at 4 °C and 46 °C (all p < 0.05). The intervals for the between-group differences were 0.6–0.7 m s⁻¹ and 2.9–3.9 m for ball speed and carry distance, respectively. Hence, the results showed that ball temperature influences both the ball speed and the carry distance. Based on the findings in this study, standardization of ball temperature should be factored into governing body regulation tests for golf equipment.
... Finite Element Analysis was undertaken to examine the effect that changing the putter body had on outbound ball speed. The simulation used the Explicit Dynamics functionality of Ansys 17.1, in line with previous published works [11]. The ball was modelled as a two-piece bonded structure, with a core and outer layer, whilst the putter body was solid aluminium ( Table 1). ...
Conference Paper
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Putting accounts for more shots in a round of golf than any other type of play. The percentage of putts holed decreases as putt length increases, because golfers struggle to achieve a consistent range and direction. Range variation has been partly attributed to the ball striking the club face away from the central plane of the putter face. Tests have shown a 30 mm off-centre impact can reduce the roll distance of a putt by 13%. In this paper, changes in mass distribution of the putter body and the addition of a flexible striking surface are considered. Physical testing and Finite Element Analysis are used to produce a club design with more consistent roll distance. Redistribution of mass reduced the roll distance variation across the clubface. Combining this with a flexible impact surface reduced the variation between a central impact and one 20 mm from center to just 1%. The proposed design could significantly reduce distance variation; aiding golfers in holing putts. Future work will optimise the design and validate through physical prototyping.
... The finite element (FE) method is widely utilized for various purposes, such as understanding the dynamic behavior of a ball and club during impact and swing and evaluating equipment. In a study on ball impact, there has been an attempt to use the impact model for the design of a clubhead by shape optimization of the clubface [5], and to develop a model for predicting the sound of a ball impacting the clubhead [6]. FE analysis for estimating the behavior of the club during the swing were conducted, but the 3D motion of the club could not be sufficiently analyzed due to the simple FE model for the club, which consisted of the beam elements for the shaft and the mass element for the clubhead [7][8][9]. ...
... The mass property insights observed by Iwatsubo et al. can also be found using IM models [67]; however the same cannot be said for other FE clubhead optimizations. For example, Hocknell [68] used experimentally validated clubhead modal characteristics and correlated them with performance and the concept of "feel", and Petersen and McPhee [69] devised a routine for determining optimal clubface shape. ...
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Advances in golf club performance are typically based on the notion that golfer biomechanics do not change when modifications to the golf club are made. A full-swing forward dynamic golf drive model, including impact and ball flight, has been developed to provide a deeper understanding of the interaction between golfer biomechanics and the physical properties of golf clubs.
... Sound is a subjective characteristic, but golfers tend to differentiate drivers in terms of perceived loudness and sharpness [2]. Computer simulation represents an alternative to physical testing, with Finite Element (FE) based structural analysis used for club design [6,7]. As highlighted by Roberts et al. [4], if impact sound could be predicted using modelling techniques, it would be possible to manipulate the acoustics of a club earlier in the design process. ...
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A model was developed to predict the sound of a ball impacting a USGA CoR plate, as a first step towards simulating the acoustics of a ball/driver impact. A ball was dropped from 2.5 m onto a free-free plate with the impact sound recorded with a microphone. The experiment was replicated in Ansys/LS-DYNA, with both the exact Boundary Element Method and the Rayleigh method applied to predict the sound. The Rayleigh method predicted lower acoustic pressure than the Boundary Element Method, and was less accurate at predicting relative amplitudes of the frequency spectrum. The models under-predicted decay time, although, increasing mesh density improved agreement with the experiment. Further work should look to improve agreement between model and experiment for decay time, while investigating the effect of impact speed for a range of plate thicknesses.
... To observe this, we traced the dependence of C R on varying k a for k b = 1000 N m −1 when all other parameters are kept constant in figure 8. Optimum C R values can be seen when k a ≈ k b . This essentially means that the transference of energy between the two vibrating systems is optimal when the mechanical impedances are matched [25]. ...
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Under the theme of collisions that occur repeatedly, we conducted easy and inexpensive experiments of rebounding spheres and Newton's cradle with two spheres to determine the coefficients of restitution using the sound record feature in modern laptops and a free and open source software called Audacity. In the rebounding sphere experiment, the coefficients of restitution of the golf and ping pong balls used were found to be 0.727???0.025 and 0.816???0.041 respectively. With the Netwon's cradle experiment, the coefficient of restitution of two steel sphere balls was found to be 0.987???0.003. The contrasts in the results obtained from both experiments permit the operational principles of a pendulum to be emphasized, and engagements to be made to consider the transfer of kinetic energy in the form of vibrational energy of the bodies' constituents. Using a one-dimensional two-mass model with spring and damper linkages to account for harmonic motions that occur during impact, we found it possible to perform a simple analysis to account for this, and how it can be linked to high energy transfer modes such as the phenomenon of resonance and impedance matching.
... The parameters m and n are determined using two additional maximum power values at a higher temperature and a lower [30]. Table 1 Thermo-mechanical properties of polymers used in simulation [23,[27][28][29][30][31][32][34][35][36][37][38][39]. ...
Article
An encapsulant in a Photovoltiac (PV) module is a polymer used for binding all the components together. It also provides protection of cells and interconnects from moisture, foreign impurities and mechanical damage. In addition to this, the encapsulant must possess certain desirable characteristics such as low cost, high transmittance of light, good thermal conduction and long operating range. The provision of such properties makes it a vital component on which the performance of a PV module depends. Currently, the PV industry is dominated with Ethylene-Vinyl Acetate (EVA) as an encapsulant, mostly due to its low cost. Other polymers such as polydimethylsiloxane (PDMS), polyvinyl butyral (PVB), thermoplastic polyurethane (TPU) and Ionomer have gained interest and are being tested for better encapsulation of PV modules. The current work deals with the comparison of the mentioned encapsulants and selecting the optimum one based on its properties such as light transmittance, UV durability, electrical insulation, water vapor transmission rate and cost. The structural life of PV module is also compared by using these encapsulants. For this purpose, previously developed structural and thermal models are coupled with electrical and life-prediction models to determine efficiency and life of PV module for each encapsulant case. Life prediction of PV module encapsulant is based on a year's data of Jeddah, Saudi Arabia where the interconnect crack initiation defines failure. Under these assumptions, a detailed structural analysis has been carried out. Finally, the results of simulation combined with the other outcomes of literature are used in a decision matrix to give Ionomer to be an optimum encapsulant for PV module.
... Additionally, studies using detailed FE models were conducted to examine the effects of different clubhead designs on the rebound behaviour of balls. 8,9 The studies suggest that more experiments are required to construct finer models and to enhance the reliability of the results obtained from their simulations. ...
Article
The objective of this study was to construct a finite element model of a golf ball and an impact simulation model between the ball and a club, and to devise a method for the construction of simulation models by investigating the factors affecting the behaviour of the ball during and after impact. A ball model with hyperelasticity and viscoelasticity was constructed using solid elements, and the relationship between the material properties and the ball behaviour at impact was revealed by varying several material constants of the ball model. A finite element model of a club with elasticity was created from a computer-aided design surface model of a commercially available driver. The club head and shaft were modelled using solid and shell elements, respectively. The effects of initial conditions at impact on the rebound behaviour of the ball, that is, the velocity, angle and spin rate, were investigated from impact simulations by varying the impact points of the ball and the postures of the club. Then, methods for the construction of simulation models were proposed based on these relationships. Impact experiments were also conducted to obtain the ball behaviour. The results simulated using the models, constructed by the proposed methods, closely matched the experimental results.