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 normally runs 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.
In this study we investigated elastomeric materials based on natural rubber used in the manufacture of rubber and rubber-metal vibration isolators. Basic anti-vibration properties were identified and stability over time was predicted. To achieve the objectives, tests were conducted on a mechanical oscilloscope Yerzley AYO-IV.
According to the research (Figure 1), we observed that replacement of the active carbon black N220 with high structural properties on the active carbon black К-354 and P-234 with a low index of structural in the ratio 1: 1 leads to a slight increase in such parameters as static and dynamic modules, hysteresis loss, and also to reduction of the coefficient of elasticity and vibration isolation.
To predict the stability of the main anti-vibration characteristics of the test material we were applied accelerated aging method according to GOST (Russian National Standard ) – 9.707 and method of prediction changes of properties during thermal aging according to GOST (Russian National Standard ) – 9.713.
According the results of the research we were constructed the graphics of combined curves (Figures 2, 3 and 4).
The replacement of the active carbon black К-354 and P-234 on the active carbon black N220 in the elastomeric material based on natural rubber led to an increase in the stability of anti-vibration characteristics in the first years of using. However, lately no significant difference was observed.
Contributed by: Maxim Myslivets and Elizabeth Burdakova, Russia
Contributed by: Dr. Sujitkumar Dutta
Not all rubber compositions are the same. It turns out that there is an optimum level of carbon black for maximum energy absorption capacity. One of our clients ran a series of tests on their Advanced Yerzley Oscillograph (AYO-IV) for Natural Rubber and Chloroprene Rubber at five different levels of carbon black. Their results show a definite maximum impact energy absorption level at 75 parts per hundred of rubber (PHR).
Dynamic parameter tests are quick and easy on our Advanced Yerzley Oscillograph, taking just two to five seconds with results evaluated instantaneously.
From a single test cycle, we determine:
- Natural frequency
- Static and dynamic moduli
- Tangent of delta and other parameters
The Advanced Yerzley Oscillograph (AYO-IV) satisfies the requirements of ASTM D945-12 and can be viewed here.