The concept of the new **“Dynamic Mechanical Yerzley Oscillograph – V” is based on the venerable “Advanced Yerzley Oscillograph – IV as per ASTM D945-16”.** Both are based on weights on an oscillating beam always testing elastomers at the **natural frequency **of the configuration.

**AYO-IV**has two possible moment arms, 5″ or 10″; whereas,**DMYO-V**has a variable moment arm that automatically adjusts between 4″ and 11″. The weight table is motorized, it can setup automatically at any specified strain.**DMYO-V**has a load cell in addition to a displacement transducer. Both load and displacement are measured simultaneously, enabling:

- The observation of the phase lag between Load and Displacement.
- The comparison of measured Phase Angle to the theoretically calculated (ASTM 5992) Loss Angle.

- The manual “Step Wise” hysteresis test of the
**AYO-IV**is fully automated on the**DMYO-V**. The static hysteresis test is user-programmable and is normally run unattended on this test machine. - The Dynamic Test on the
**DMYO-V**is automated with a magnetic trigger, which enhances repeatability. - The data processing and parameter evaluation procedures have been improved with noise elimination and data-smoothing algorithms.
- Minima and Maxima detection mechanisms use least square error curve fitting to improve accuracy. This is crucial for evaluating phase angles.

**Figure 1.** Point Modulus and Dynamic Modulus vs. Measured Load for NR with Shore A 40.

**Figure 2.** Point Modulus and Dynamic Modulus vs. Measured Load for NR with Shore A 70.

Here are some points to stress to the engineers and the technicians of the compounders, process engineers, sales engineers, and so on.

**Automotive door seals:**Dynamic Modulus (low values), Dynamic/Static Ratio of moduli (low values), help to design the automotive door seals correctly for better sound-proofing and longevity.**Engine mounts:**Yerzley Resilience (low values) and Yerzley Hysteresis (higher values) as well as Impact Energy (low values), Phase angle (high values) will absorb vibration energy much more efficiently for smooth riding.**Windshield wipers:**Dynamic Modulus (low values), Dynamic/Static Ratio of moduli (low values), helps to design the wipers correctly for better and long-term wiping function. Climate change (summer & winter) should have minimal effect on the wiping function.**Seismic Pads in construction industry:**Dynamic Modulus, Impact Energy, Phase angle all have to have high values for high damping function. Natural frequency around 5 to 9 Hertz may also be useful for the design criteria.