Long Term Performance/Durability Testing

Smithers Rapra has provided long-term design data to confirm the durability of product and component designs for over 30 years. Our consultants have access to our fully equipped long term creep and fatigue onsite laboratories. Operating at extremes of temperature and in aggressive chemical environments the labatories can reproduce years of real world exposure in a period of weeks.

The cost of product recall to your brand and possible litigation due to premature failure explains why this type of testing is becoming seen as a necessity, and highly recommended. The cost is now quite often seen as an integral part of product design.

Visco-elasticity

All polymer materials are visco-elastic in nature and respond to stress as if they were a combination of elastic solids and viscous fluids. Consequently they exhibit a non-linear stress-strain relationship and their properties depend on a variety of factors and their combinations; the time under load, operating temperature, the environment and the level of stress or strain applied.

In simple terms mechanical properties of a polymer will deteriorate with time. The rate at which a Plastic or rubber will decline may be accelerated by an increase in temperature, an increase in applied load or number of stress cycles and detrimental effects of the surrounding environment.

Ignoring the significance of a polymers visco-elastic nature at the design stage will result in under designing and the increase in likelihood of premature failure in use.

To avoid under designing, properties such as creep rupture strength, creep modulus, fatigue strength must be determined experimentally in laboratory conditions under worst-case scenario operational conditions. Test conditions include maximum envisaged service temperatures, maximum stress and environmental effects.

For any engineering component subjected to long term static or dynamic loads, elevated temperature and the environment a thorough understanding of the long term properties of the material is central to guaranteeing the durability of the final product.

Durability Testing

Smithers Rapra generates the design data for thermoplastics, thermosets, elastomers and composites to allow realistic designs of structural polymer components through the following tests:

• Tensile creep rupture
• Tensile creep
• Fatigue testing - Sn curve generation
• Compressive creep
• Hydrostatic creep - hoses, pipes
• Stress relaxation
• Thermally accelerated ageing & testing