Cyclic Testing of Polymer Composites and Textile Cords for Tires

Area of Science:

• Materials Science
• Mechanical Engineering
• Polymer Science

Background:

• Polymer composites and polyamide 66 (PA66) cords are vital reinforcement materials.
• Accurate material parameters are essential for computational tire simulations.
• Existing testing methods may not fully capture the complex behavior of these materials under cyclic loading.

Purpose of the Study:

• To validate novel low-cyclic testing methodologies for polymer composites and PA66 cords.
• To characterize material parameters for use in computational tire simulations.
• To evaluate the effect of temperature on the mechanical properties of PA66 cords.

Main Methods:

• Development of experimental methods for low-cyclic testing of polymer composites and PA66 cords.
• Cyclic loading performed at 20 °C and 120 °C with a 60-second hold step.
• Utilized video-extensometer technique for precise strain and stress measurements.
• Adherence to DIN 53835-13 standard for initial textile cord testing cycles.

Main Results:

• Identified the fourth cycle as a stable cycle for polymer composites, with a 1.6% stress change between the fourth and fifth cycles.
• Obtained true stress-strain (elongation) and force-strain dependencies for composites and PA66 cords, respectively.
• Established a second-degree polynomial relationship between stress and cycle loops for composites.
• Developed a simple relationship to describe force values at cycle ends for textile cords.

Conclusions:

• The developed testing methods effectively characterize material parameters for computational tire simulations.
• Temperature significantly influences the material properties of PA66 cords.
• The obtained data provides valuable input for accurate modeling of tire casings.