ISO 22675

ISO 22675 – CYCLIC TEST

The cyclic test outlined in ISO 22675 plays a crucial role in evaluating the functionality of ankle-foot devices. It assesses their ability to withstand the forces and stresses encountered during normal walking. By subjecting the devices to simulated real-life loading conditions, the test helps ensure that they meet the necessary performance standards.

This test, utilizing a pulsating test force and tilting angle, simulates the loading conditions of the complete stance phase of walking and verifies the strength, durability, and service life of the devices.  Each loading condition generates compound loadings that simulate walking and other single events of loading. The test applies to ankle-foot devices and foot units of any size by establishing a relationship between the position of the top load application point and foot length.

• For the cyclic fatigue test, the specified number of cycles is 2×10^6.

In the 2024 version, cyclic testing is now linked to newly introduced Test Ranges (R2, R3, R4), each with defined walking characteristics, number of cycles, and angular conditions (like toe-out and tilt). This structure allows tailoring the test to the intended use and user mobility level.

Each range defines unique cyclic loading parameters based on intended mobility level and user activity. It includes:

• Number of load cycles
• Tilting and toe-out angles
• Application positioning based on foot length

This modular structure allows more realistic and targeted fatigue testing.

ISO 22675 – STATIC TEST

In addition to the cyclic test, ISO 22675 also covers three static tests to evaluate the structural strength of ankle-foot devices:

• Static proof test
• Static ultimate strength test
• Static torsion test (introduced in 2024)

The 2024 edition adds a detailed method to assess shock absorption capacity, measuring the energy absorbed during deformation. This includes applying load until failure or significant deflection, calculating both actual and theoretical energy, and verifying compliance against defined thresholds.

It also introduces a separate static torsion test to evaluate resistance to twisting loads. The method combines vertical and torsional loading and measures angular deformation, offering a new perspective on real-world performance.