Long Term Performance/Durability Testing

Smithers Rapra has provided long-term design data to confirm the durability of product & component designs for over 30 years. Our consultants have access to our fully equipped long term creep & fatigue onsite laboratories. Operating at extremes of temperature & 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 & possible litigation due to premature failure explains why this type of testing is becoming seen as a necessity, & 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 & respond to stress as if they were a combination of elastic solids & viscous fluids. Consequently they exhibit a non-linear stress-strain relationship & their properties depend on a variety of factors & their combinations; the time under load, operating temperature, the environment & 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 & detrimental effects of the surrounding environment.

Ignoring the significance of a polymers visco-elastic nature at the design stage will result in under designing & 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 & environmental effects.

For any engineering component subjected to long term static or dynamic loads, elevated temperature & 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 & 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