Sports surfaces

Table 3. Physical Parameters for Ball Response from Sports Surfaces...

Hoetzeldt, K., Bochmann, G., and Passler, W., Cold sprayable, low flammability and watertight molding or sealing material used for the preparation of elastic work layers for road, play or sports surfaces, German Patent, DE 4416570 A1 19,951,116, 1995. 

For many applications it is not possible to put a component into service to test its durability. Similarly, in product testing one cannot always simulate full service conditions in one test or things become too complicated - for example, time-dependent loading plus abrasion plus environmental ageing. Car tyres have a complicated pattern of cornering, sports surfaces are subject to the actions of different sports and pipes in the North Sea have almost unpredictable wave motions superimposed. No simulation test will reproduce service conditions perfectly, therefore, in accordance with Section 4.13, the test has to be restricted to the critical agents of degradation. 

Where a number of properties are relevant to a product the testing may be carried out with a sequence of tests without superimposing any ageing. Where environmental effects have to be accounted for they are applied separately and the rig tests repeated. An example of this approach is artificial sports surfaces where such characteristics as ball bounce, energy absorption, dynamic stiffness and spike resistance are measured using specifically developed rigs. 

The friction of road surfaces is often measured with a skid tester developed by the Road Research Laboratory17 and this has also been widely used on other surfaces and floors, including artificial sports surfaces. It is a pendulum device, the movement of which is arrested by the foot of the pendulum skidding on the surface to be measured. The skid resistance indicated can be approximately related to coefficient of friction by ... 

The Schiefer abrader, which is also known in Britain as the WIRA carpet abrader, is of the form (e) in Figure 11.4. Its principal feature is that it produces a constant relative speed between the test piece and abradant at all points on the test piece, whilst the direction of relative motion changes steadily around a full circle. It is a versatile machine in that a variety of test piece holders can be fitted and the abradant is readily changed, including the use of serrated metal surfaces. It is used for testing polymeric artificial sports surfaces. 

S ries 34. [Syn. Surfaces] Patented instant grab adhesives for factoiy bonding of automotive parts and panel assemblies, outdoor installation of roofing, sport surfaces, marine and construction materials under adverse conditions. 

Optical parameters, which are properties of the surface, gloss, reflectance, and color, are in principle relevant to all polymer materials, but it is not frequently that rubbers and foams are used where these aesthetic qualities are important. Not that these properties are entirely a matter of appearance, because color and reflectance are important in terms of solar energy reflected and hence the temperature rise in an exposed material. Roofing sheet is a particular example, but generally the color would only need to be approximately matched. Gloss is also important in terms of glare from a surface and would be controlled in such products as artificial sports surfaces. Surface texture will affect gloss and reflectance and how a surface looks, but it is not in itself an optical property. 

Energy absorbent methods have been widely used by the footwear and flooring industries, for example the apparatus described by Wilson and Mahoney [21). Energy acquired by a trolley running down an incline is absorbed by the braking action of a heel on the horizontal test surface at the base of the incline. A similar test appears in BS 7044 [22] for artificial sports surfaces. 

In sports such as athletics, traditional materials have been almost completely replaced by synthetic materials. Sports surfaces in modern indoor stadiums are usually made from a porous structure of rubber crumb and a binder such as polyurethane. Other polymeric materials used include flexible PVC or rubber sheet, polyolefins, polypropylene (PP) grasses, and foam laminates. 

Sport surfaces, roofing, walkways, landfill and budding membranes, flooring systems, underlayment... 

Sports Surfaces. The interactions of athletic shoes or equipment and the sports surface play a lai e role in performance and can result in injuries. Surfaces may vary even within a sport, such in as tennis and soccer. Information about these interactions is used by shoe manufacturers and other manufacturers to design equipment that will reduce injuries and optimize performance. Traction-test devices are used to simulate conditions in some cases. A traction-test device is simply a shoe surface that is mounted on a plate that can be tested on various surfaces. 

Friction. Surface characteristics of balls, fields, and other sports equipment will affect sports performance. The interactions between the athlete s skin and grip mnst be considered in these circumstances in addition to environmental conditions such as moisture. The effects of sports surfaces on human skin is also studied to reduce injuries. 

This area of sports engineering has overlap with biomechanics since it involves the interaction of the skin and other tissues with the sports equipment or sports surface. 

Polyurethanes are also used in the construction of sport surfaces such as all-weather athletic areas, outdoor game areas, children s playgrounds, tennis courts, and multisport halls. The poly ether polyurethane systems, mainly based on PMDI, are applied by a pour-in-place method. Often additional rubber granules are added to the system. 

Fibres Artificial sport surfaces, monofilaments for rope and cordage, stretched tapes, woven carpet backing, packaging sacks and tarpaulins, staple fibres, coarse fibres, filament yarns, fine fibres... 

Details of good quality, reliable varieties for England and Wales, from UK and European plant breeders, can be found in the Recommended Grass and Clover Lists leaflet which is funded by the Grass Levy Scheme and is published annually using data from trials carried out by NIAB TAG and evaluated by a panel of experts. Farmers in Scotland and Northern Ireland have access to information of a similar quality published by SAC and DARD respectively. Seed catalogues and the online information provided by reputable seed merchants can also be valuable sources of information. Details of grasses which have been bred for amenity and sports surfaces are provided by the Sports Turf Research Institute (STRI) also on an armual basis. 

The proportions for rubber would be expected to be not dissimilar, although there are probably differences for particular products. Tyres are particularly exposed to misuse by the public and play and sports surfaces have probably had a high proportion of failures due to quality control. 

Large areas such as the shock pads of artificial sports surfaces can experience very considerable dimensional changes due to temperature. In one particularly baffling case artificial grass appeared to expand and formed waves when the temperature was lowered. The effect was found to be a result of internal stresses and the differential expansion between the grass and the mbber shock pad. 

In the last 25 years, PP proved, by its qualities, to be the best fiber for synthetic sport surfaces, due to its low price, player comfort, ball-surface interaction and durability, response to UV and visible light, frictional properties, environmental aspects, and playing characteristics [733-742]. 

Sport surfaces must resist temperatures between —35°C (cricket games in Canada) up to - -60°C (bowling green in Spain). 

---