Creep Curve

One of the most important consequences of the viscoelastic behavior of plastics, creep is the deformation that occurs over time when a material is subjected to constant stress at constant temperature. Under these conditions the polymer chains slowly slip past one another. Because some of this slippage is permanent, only a portion of the creep deformation can be recovered when the load is removed.

Creep data such as isochronous stress-strain curves provide a means for predicting a material's behavior. Each curve represents the material behavior for different loading durations.

If you are designing parts for long-term loading, particularly for elevated-temperature service, you must account for creep characteristics.  To predict creep, substitute an apparent modulus for the instantaneous elastic or Young’s modulus in structural calculations.

• Introduction
• Mechanical Properties
  • Stress-Strain Curve
  • Creep Curve
  • Fatigue
  • Impact Strength
• Thermal Properties
• Environmental Considerations
• Design
• Assembly
• Machining
• Finishing