Relaxation Diagrammatic example of stress retention versus time

Thermoplastics being sensitive to creep, the fatigue tests at defined strain are less severe than those at defined stress for comparable original stresses. 

The results depend on the stress type and level, the frequency, the surrounding temperature, and the geometry of the sample. We must note that the temperature of the material rises under the dynamic loading with the usual consequences, such as modulus reduction and ageing. Depending on the thermoplastic, stress can  

Polymers are organic materials and are sensitive to natural or artificial UV sources. This is of primary importance for outdoor exposure of unprotected parts and for some industrial applications such as electrical welding, photocopier light exposure devices. .. 

Additives such as special fillers (carbon blacks, for example), UV stabilizers and so on can enhance the basic resistance of the matrix to UV. 

Under quite precise conditions (angle of incidence, positioning, temperature, water vapour, surface water. ..), tests can be done by exposure  

---

Figure 3.8. Relaxation diagrammatic example of stress retention versus time...

---