Rubber products are defined by mechanical elasticity, obviously, but what if we were to change the context of this descriptive term? Mechanically elastic by design, the products created by the material also display elastic versatility, a number of variable features that go far beyond its stretchy physical properties.
The Shore hardness scale uses durometers (calibrated indentation measurement devices) to balance the elastic modulus of a stated rubber against its viscoelastic behavior. The resulting figure appears somewhere on the Shore spectrum, a hardness scale that determines whether the rubber is suitable for its application. Most elastomers appear on the Shore ‘A’ scale but harder rubbers do appear on the Shore ‘D’ scale. Car tires and heavy lifting vehicles have a midpoint Shore ‘A’ hardness grade while shoe soles and ‘O’ rings are softer. Softer rubber products earn a low Shore rating, perhaps somewhere around the 20A or 30A mark.
This metric verifies the resistance of the product, its ability to withstand physical stress. A versatile rubber with a high tensile rating is typically used in engineering applications. The material will absorb heavy shocks without losing its base elastic properties. Elastomeric bearings on bridges and seismic structural supports use these incredibly strong rubber products.
A number of conflicting forces can undermine the best engineering rubbers, which is why an engineer models the product to cope with these form-degrading influences. These forces include elongation, a natural attribute for rubber, but this one force can combine with compression, torsion, and shear. The product must then exhibit factors that guarantee consistency over time even if these forces are repeated thousands of times per day.
Under the physical domain, the inbuilt elasticity of an elastomer manages the above forces and returns the product to its original form. Physical resilience is a little more challenging to incorporate. Rubber assemblies are placed in mining and quarrying facilities. It’s here and in other heavy industrial applications that they’re battered and scratched, scraped and chafed. The material must exhibit long-term wear resistance characteristics when placed in this environment.
In closing, we finish with the chemical makeup of rubber. Ultraviolet radiation weakens rubber. Corrosive chemicals eat into the material and age it, leaving the product unable to stretch or compress. A properly engineered rubber creation is engineered to endure these attacks and function with compressible, elongating versatility as designed by its originating material architect.