Testing Products for ASTM D7791
APP-D7791Determines the uniaxial fatigue properties of plastics under constant amplitude of force or deflection. This method is used to characterize the fatigue life and crack propagation behavior of polymers. The Newton-Series controller manages the dynamic control loop, utilizing 32-bit acquisition to monitor cyclical stress-strain behavior. The 100,000 SNR is essential for distinguishing actual material fatigue phenomena from electrical noise artifacts. The load frame is configured to handle the specific cyclical load frequencies and amplitudes required by the standard. This setup ensures a technically compliant and cost-effective solution for plastic fatigue characterization, minimizing unnecessary hardware overhead.
Phase Shift: High-frequency cycling can introduce a lag between force and displacement data.
Use Newton’s 64-bit math processing to ensure real-time synchronization of load and strain channels.
Regulatory & Test Details
| App Id | APP-D7791 |
|---|---|
| App Standard | ASTM D7791 |
| Standard Organization | ASTM |
| Test Type | Fatigue |
| Material Type | Plastics |
| Specimen Type | Molded Bars |
| Industry Type | Consumer Goods, Medical |
| Min Force Kn | 1 |
| Max Force Kn | 50 |
| Max Spd Mm/m | 500 |
| Expert Spd | Dynamic frequency dependent. |
| Pointer App Software | N-ASTM-D7791 |
| Pointer Fixture Family | G-ASTM-D7791 |
| Pointer Strain Family | E-ASTM-D7791 |
Implementation Commentary
Frame stiffness is critical here; system compliance under cyclical loading can lead to amplitude decay.
Common Pitfalls
Testing above 200 Hz without verifying the dynamic force limits of the load frame.