Deflectometer: E-ASTM-D790 Model: E-ASTM-D790
A deflectometer measures the actual mid-span deflection, which is much more accurate than crosshead data. Note you need a deflection software module to track the bottom edge of the bar at mid-span.
ASTM
Epsilon 3540
Deflectometer
Technical Specifications
| Specification | Value |
|---|---|
| Model | E-ASTM-D790 |
| Industry Std | ASTM D790 |
| Test Type | ASTM |
| Family Id | Epsilon 3540 |
| Fixture Type | Deflectometer |
Expert Commentary
Flexural Deflection Accuracy: In 3-point bending, measuring deflection via crosshead travel includes the compliance of the support rollers and the machine frame. Under ASTM D790, a Deflectometer (Epsilon 3540) placed at the mid-span is the gold standard. It measures the true sag of the bottom edge of the bar. Because the strain is highest at the outer fibers, even a 0.01mm error in displacement tracking leads to a massive error in the calculated flexural modulus.