Striking Face Research Articles

Polyurethanes for potential use in transparent armour investigated using DSC and DMA

A material combination that may be applied as transparent armour is glass-clad polyurethane. These are comprised of a relatively thin glass strike face and a relatively thick (transparent) polyurethane backing layer. Three transparent polyurethane samples were investigated using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The DSC results identified the glass transitions and in some cases the melting and crystallisation processes. The DMA experiments were only performed on heating around the glass transition region to further investigate this transition. The experiments were performed at three different frequencies (1, 10 and 100 Hz); the shift of the glass transition with the frequency was clearly observed. The method of time-temperature superposition was used to extrapolate the results to higher frequencies as the magnitude of the strain-rate occurring within ballistic applications is in the order of 1000 s-1 or higher. Polyurethane with a rubbery behaviour at normal (low) strain rates can be stiff and brittle when used as an armour component (temperature below its dynamic T g value). © 2011 Akademiai Kiado, Budapest, Hungary.

Impact Force Dampening System For Use With A Golf Driver Or Fairway Club Head

A force dampening and redirection system for use with a golf driver or fairway club head including an elongated handle terminating in a three-dimensional shaped driver or fairway head exhibiting a substantially smooth ball striking face. A vibration dampening and absorbing component, such as an elongated spring, extends within a hollow three dimensional interior associated with the club head. Upon impacting a golf ball offset from a center line associated with the striking face, an off-center striking force is more readily transferred to the spring, both to counteract twisting of the putter head and to reduce vibration of the club face at the ball contact zone, thereby increasing an effective surface area of the striking face creating a perpendicular travel direction of the ball relative to the golf club striking face.

Extreme Weighted Hybrid And Other Wood-Type Golf Clubs And Golf Club Heads

Wood-type golf club heads include: (a) a club head body member defining an interior chamber; (b) a weight system engaged with a rear perimeter portion of the club head body member; and (c) a connection system connecting the weight system with the club head body (e.g., with the rear of the ball striking face portion). The club heads further may include one or more damping members in the interior chamber to alter the sound and/or otherwise attenuate a vibrational response of the club head. The damping members may extend between the ball striking face and the weight system, and optionally may engage the connection system. The damping member(s) may constitute a foam material compressed within the interior chamber of the club head. Methods of making such golf club head structures also are described.

New Interference Approach for Ballistic Impact into Stacked Flexible Composite Body Armor

In this study a new interference model is developed to investigate the ballistic response of a hybrid, two-layered, flexible body armor. Because the stacking order of layers, which have distinctly different mechanical properties, has a large effect on the V 50 limit velocity for penetration, we apply the analysis to a two-layer system consisting of fabrics of aramid (Kevlar29®) fiber and of ultrahigh molecular weight and drawn polyethylene (Dyneema@) fibers. Using right-circular cylindrical projectiles, previous experimental results of Cunniff (An Analysis of the System Effects in Woven Fabrics Under Ballistic Impact, Textile Research Journal, Vol. 62,1992, pp. 495―509) [using a similar fiber, Spectra@ instead of Dyneema®] showed nearly a factor of 2 difference in the V 50 velocity in the two possible stacking orders, that is, Spectra@ versus Kevlar29® as the strike face. This new model extends our previous fundamental work (A New Membrane Model for the Ballistic Impact Response and V50 Performance of Multiply Fibrous System, International Journal of Solids and Structures, Vol. 40, 2003, pp. 6723―6765) by addressing interference factors in terms of instantaneous material inflow to the impact cone using a convolution over current local strain around the projectile edge during its deceleration. Our previous multilayer model (Modeling of System Effects in Ballistic Impact into Multi-Layered Fibrous Structures for Soft Body Armors, International Jourual of Fracture, Vol. 135, 2005, pp. 219―251) ignored the interference aspect though a subsequent work (Effects of Layer Stacking Order on the V50 Velocity of Two-Layered Hybrid Armor System, Journal of Mechanics of Materials and Structures, Vol. 3, 2008, pp. 627-639) approximated its effects but without instantaneous response of material inflow to local tensile strain. The current model is much more complete and produces velocity, strain, and deformation histories either to perforation or to halting the projectile. In the new model, V 50 velocity differences with stacking order and with layer bonding versus no bonding are even larger. However, backface deflections turn out to be minimally affected. Calculations are very fast and postprocessing figures can be obtained in less than a minute using MATLAB with a laptop (2 MHz Core 2 Duo CPU 2 Gb RAM).

Impact force dampening system for use with a golf putter head

A golf putter including an elongated handle terminating in a three-dimensional shaped putter head exhibiting a substantially smooth ball striking face. A vibration inducing component being mounted to first and second locations associated with a surface of the putter head and located opposite the ball striking face. Upon impacting a golf ball offset from a center line associated with the striking face, the vibration inducing components counteract twisting of the putter head, thereby increasing an effective surface area of the striking face creating a perpendicular travel direction of the ball relative to the putting face.

Putter with vibration isolation

A golf club head with a vibration dampening insert is disclosed. The club head includes a face member, a dampening member, and a body member. The dampening member is sandwiched between the face member and the body member and extends along a large percentage of the face member. The dampening layer attenuates vibrations, providing consistent feel across the length of the striking face.

At golf club head providing enhanced acoustics

An golf club head is provided, having enhanced sound and feel characteristics. The club head has a hollow main body including a ball-striking face, a sole, a crown, a hosel, and a side portion extending rearwardly from the face. The body further includes a heel region adjacent to the hosel and a toe region opposing the heel region, and it defines a volume of at least 100 cc. The club head further includes a stiffening member disposed within the body and attached to both the sole and the crown. The member is spaced apart from the striking face and disposed within the body in a region having a first zone extending less than half the distance from the heel region to the toe region and a second zone extending less than half the distance from a rearmost point, thereby forming a local stiffness zone in the body to influence vibration modes and acoustic properties of the club head in a prescribed manner.

The effect of a carbon-nanotube forest-mat strike face on the ballistic-protection performance of E-glass reinforced poly-vinyl-ester-epoxy composite armour

In the present work, a ballistic material-model development approach is combined with transient non-linear dynamics simulations of the projectile/armour interactions to explore the armour-hard-facing potential of multi-walled carbon nanotube (MWCNT) reinforced, poly-vinyl-ester-epoxy (PVEE)-matrix composite mats. This approach is applied to improving the ballistic-protection performance of E-glass fibre-mat reinforced PVEE-matrix laminate armour. Two different architectures of the MWCNT-reinforced/PVEE-matrix composite mats were considered: (a) a MWCNT-ply mat structure in which the MWCNT reinforcements are aligned parallel to the armour faces and (b) a MWCNT-forest mat structure in which the MWCNT reinforcements are aligned orthogonally to the armour faces. The projectile/armour interaction simulation results showed that, at low volume fractions of MWCNTs, both armour architectures yield no discernable increase in the armour ballistic-protection performance as measured by the armour. On the other hand, at high MWCNT volume fractions of MWCNTs, the first armour architecture remained ineffective whereas the second showed a minor improvement in the ballistic-protection performance relative to the corresponding monolithic armour. These results were rationalized using published experimental observations pertaining to the effect of MWCNTs on the in-plane and the through-the-thickness properties of fibre-mat/polymer-matrix composite materials.

Ballistic Resistance of 2D and 3D Woven Sandwich Composites

In the present study, the ballistic resistance of sandwich composite structures for vehicle armor panel applications is investigated. The core material of each sandwich structure is a layer of tiled alumina ceramic, combined with a layer of two-dimensional (2D)/three-dimensional (3D) S-2 glass-based woven composite laminate, sandwiched between 2D plain weave composite skins. The 2D composite backing consists of a plain woven fiberglass, with fiber orientation predominantly in the direction of plane of the weave. The 3D contains similar in-plane fiber preform structure, with the inclusion of an integral through thickness fiber, creating a 3D structure. The ballistic performance of sandwich composite with several types of 3D woven backings is compared to the baseline 2D plain weave backed sandwiched composites. An IMACON 200 high-speed camera is used to obtain high-speed photographs of the ballistic events of penetration and damage. These images are analyzed to study the real-time damage mechanism of the strike face surface of several targets and subsequently to obtain average resistive force of target points during impact. The velocities of the projectile (M2AP armor piercing bullets) are recorded in all the experiments, and they range from 915 to 975 m/s. Postmortem analyses, which include through thickness sectioning, are performed on each sandwich structure. The results show that armor panels with 3D woven backing have a higher ballistic efficiency than the 2D baseline panels, strike face damage mechanics are predominantly axisymmetric about the impact point and the panels with 3D backing had controlled delamination and fewer complete penetrations.

Method of evaluating restitution characteristic of golf club, system for evaluating restitution characteristic, and golf club

A method of evaluating restitution characteristics of a golf club head, a system for evaluating the restitution characteristics and a golf club, are provided in which a coefficient of restitution of a golf club head is inferred and obtained without disassembling the golf club by removing the golf club head away from a shaft and the coefficient of restitution may extremely easily be obtained for a short period of time. At first, an external force to a striking face of the golf club head is imparted to perform impact vibration. A response signal of the striking face under the impact vibration is acquired to obtain a resonant frequency of the striking face. A coefficient of restitution is calculated from the resonant frequency when the golf ball is struck by the striking face, whereby restitution characteristics of the golf club head are inferred and evaluated.

Against the New Internationalism

When I think of the challenges facing international society in the wake of the invasion of Iraq, two images come to mind. The first, a work of postcard art, depicts a screenprint of the Statue of Liberty, with a twist. In the place of her striking face and radiating crown appears a decidedly masculine image: that of a helmeted marine, grim and tight-jawed, a cigarette poking insolently from his lips. The caption reads, in bold white capitals on black, “PEACE,” and beneath it another phrase, asterisked: “conditions apply.” The second is a newspaper photograph of a young woman in New York taken during the global demonstrations against the war in February 2003. She has been called out of the march by the photographer and stands, at once defiant and bewildered, against a row of mounted police. Rugged up against the winter cold, she holds a placard upon which she has written a question: “Perpetual war for perpetual peace?”

De Lange syndrome: subjective and objective comparison of the classical and mild phenotypes.

Classical de Lange syndrome presents with a striking face, pronounced growth and mental retardation, and variable limb deficiencies. Over the past five years, a mild variant has been defined, with...

Sounding golf putter

A golf putter includes a rigid mid-section and two parallel, opposing tone-generating tines on either side. The tone generators are each held at the toe of the club head, being formed as an integral extension of a central member by cuts through the club head. Thus, a volume and quality of sound can be produced from a relatively thick striking face plate which has minimum flexure to produce accurate golf putting. Because the structure is symmetrical, it is reversible for use by both left and right-handed golfers. The sound-producing tines may alternately both be placed on the rear side of the club head away from the striking surface. In this case, the sound-producing tines may be of different lengths so each tine produces different tonal frequencies that are preferably mutual tonal harmonics.

On the ballistic performance of metallic materials

The paper presents a ballistic performance index for metallic armour materials in terms of the commonly determined mechanical properties such as strength and modulus. The index is derived using an energy-balance approach, where the kinetic energy of the projectile is assumed to be absorbed by the elastic and the plastic deformation involved in the penetration process as well as the kinetic energy imparted to the target material during deformation. The derivation assumes two distinct stages to exist during the penetration of the projectile. At the striking face of the armour, the material is assumed to flow radially in a constrained deformation region but longitudinally at the rear surface leading to typically observed bulging of the armour without constraint. The index is validated using the available experimental and empirical data obtained in the case of small arm projectiles for an impact velocity of about 800 m/sec. This index is expected to facilitate the development of metallic armour, since the number of the ballistic experiments can be reduced significantly and only the promising materials need to be considered.

Impact of Delrin disc: lubricated and dry contacts

A Delrin disc is used in the Björk-Shiley tilting disc heart valve (H.L. Milligan, B.M. Johnson and P.A. Engel, ASTM J. Test. Eval., 22 (5) (1994) 474–484; C.G. Montero et al., Ann Thorac. Surg., 37 (4) (1984) 328–336), where dynamic contact occurs between metallic cylindrical struts and the disc, during valve action. To investigate the wear behavior of the Delrin disc, impact wear tests were performed by using a pivotal hammer device with a spherical striking face. For the biomedical wear study (Milligan et al.), raised temperature (36.6°C) and lubrication (simulating blood flow) was always provided, but in the present work both dry and lubricated contacts were investigated in order to compare wear mechanisms. For a small (sharp) indenter radius, plastic deformations of the Delrin occurred under the initial impact cycles. These incremental plastic deformations diminished under subsequent impacts, and were later followed by completely elastic contact, contributing ‘zero wear’. Beyond this region, a measurable wear regime would start. At severe contact stress (sharp indenter), an accelerated wearing pattern was seen to start at some stage during the measurable wear range. Taking into account plastic deformations existing at the beginning of the wear process, the present work discusses an impact wear model. The combined effects of wear, shear friction and crack propagation are discussed.

Golf club head having vibration damping means

A golf club head including a front strike face, a sole extending rearwardly from a bottom region of the front strike face, a rear surface opposed to the front strike face, and a vibration damper provided on the rear surface. The vibration damper includes a constraining member having a high Young's modulus connected to the rear surface of the club head through an interposed visco-elastic material.

Czartoryski and His Essai sur la diplomatic

If we wish to progress we must have an ȯbject we have not yet attained. And in order to be always in progress we must be capable of conceiving an object which will never be attained.Prince Adam Czartoryski Memorandum to Tsar Alexander I (1803)The first book of Tolstoy's War and Peace contains an episode from the Allied War Council at Olmütz, on November 27, 1805, five days before the Battle of Austerlitz. With the Council over, Prince Andrei Bolkonsky takes Prince Boris Drubetskoy, a new aide-de-camp, to present him to Tsar Alexander. Coming out of the emperor's room as they approach is a tall man in civilian dress who has a striking face and sharply projecting jaw, which gives him a peculiar vivacity and keenness of expression. “Who was that ?” asks Drubetskoy. “He is one of the most remarkable but to me most unpleasant of men—the minister of foreign affairs, Prince Adam Czartoryski,” replies Bolkonsky.

Wind silencers for your car

This study aimed to design soft body armour by evaluating the effects of panel configuration and hybridisation. Panel configuration was studied in terms of positioning of unidirectional (UD) and woven fabrics. Hybridisation was studied by using fabrics woven from high-modulus polyethylene yarn and very high-modulus aromatic fibre yarn and also through shear thickening fluid (STF) impregnation. These customised woven fabrics in combination with commercially available Dyneema® SB51 UD sheets (250 g/m2) were used to prepare ten different soft armour panels, having areal density of around 4.9 kg/m2, which varied in the layering sequence of UD, woven neat and woven shear thickening fluid impregnated fabrics. Evaluated for ballistic performance in terms of back face signature against 9 × 19 mm lead core bullet fired at 430 m/s impact velocity, the panels showed better performance when UD fabrics were placed at the strike face and shear thickening fluid treated very high-modulus fabrics at the back face. The experiments showed that ballistic performance can be altered by strategic layer sequencing.

Street Traffic Signals, 1868–1934

IN 1868 the City of Westminster introduced a method of mechanical signalling to help the police to control the traffic. A semaphore, having a red and green gas lamp for night use, was employed, but unfortunately an explosion put an abrupt end to this experiment. Early in this century, road signals similar to railway signals were used for controlling a few tramways and also the traffic on Tower Bridge. So back as 1918, colour light signals were used to control street traffic in New York. The Siemens and General Electric Railway Signal Co. (S.G.E.) installed the first modern British traffic signal at a busy road junction in Wolverhampton in 1926. The most recent development of the vehicle-actuated signals is the ‘Autoflex’ system of the S.G.E., a full description of which is given in the Engineering Supplement of the Siemens Magazine for April. It was first brought into use in November 1933 and there are now several installations giving very satisfactory service. In this system vehicles approachmg a road junction pass over pneumatic detector mats, installed in the paths of the various traffic streams, and so notify their movements to an electrically operated controller. The mats are equivalent to the eyes and ears of a traffic policeman. If vehicles leave the intersection on the wrong side of the road the mats are insensitive. The top of the mat is rounded and projects slightly above the road level presenting a good striking face, so that it is not possible for high-speed vehicles or caterpillar tractors to ride over it without registering. If no suitable gap occurs within a predetermined time, the continuous stream is arbitrarily interrupted and the right of way transferred. There is no necessity for long ‘amber’ periods since signal changes take place only when the intersection is clear; two or three seconds are generally sufficient. The power required for a controller is only about 30 watts, which is less than that required by an ordinary lamp.