Information on the most widely used ASTM standards within the materials testing industry
ASTM F1800 Cyclic Fatigue Testing of Metal Tibial Tray Components of Total Knee Joint Replacements, covers a procedure for the fatigue testing of metallic tibial trays used in knee joint replacements using a cyclic, constant-amplitude force. It applies to tibial trays that cover both the medial and lateral plateaus of the tibia. This practice may require modifications to accommodate other tibial tray designs.
Applicable to tibial braces covering both the inner and outer sides of the tibia.
Cantilever loading,
with a frequency not exceeding 10Hz,
R=0.1,
for a period of 5 million cycles or until specimen failure in fatigue testing.

UnitedTest UTDS series electromagnetic equipment provides precise sine wave load control, offering comprehensive testing tooling to meet the experimental condition requirements in the standards, as well as accurate and effective experimental plans (SOP), helping in the mechanical performance analysis of tibial braces.
Test Method and Fixtures
Cyclic Loading Parameters:
| Parameter | Value | Rationale |
|---|---|---|
| Load Type | Sinusoidal or smooth non-sinusoidal waveform | Simulates natural joint loading |
| Peak Load (Pmax) | Typically 900 N (manufacturer-specified) | Represents 2-3 times body weight |
| Load Ratio (R) | 0.1 (Pmin = 10% of Pmax) | Maintains compressive baseline |
| Frequency | 0.5-10 Hz (cycles/sec) | Mimics normal activity levels |
| Test Duration | 10 million cycles or until failure | Equivalent to 1-2 years of moderate use |
| Fixture Element | Function | Design Requirements |
|---|---|---|
| Tibial Holder | Fixes tray as cantilever beam. | Prevents abnormal stress concentrations |
| Load Applicator | Delivers cyclic force. | Self-aligning to prevent bending moments |
| Spacer | Distributes load, prevents fretting. | UHMWPE or acetal copolymer, spherical recess |
| Measurement System. | Tracks displacement, strain. | Non-contact preferred (e.g., laser sensors) |
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