Cycle count is only one part of fatigue validation. Fixtures, travel, frequency and temperature that differ from service can produce a passing result that does not represent field life.
Reproduce the operating window
Set minimum and maximum positions, preload, direction and any impact. Travel should come from actual mechanism motion rather than an arbitrary larger stroke.
Frequency is not only about speed
High frequency can create heat, friction or dynamic effects that change the failure mode. Record sample temperature and confirm the mechanism remains representative.
Define failure
Fracture is only the most visible criterion. Load loss, free-length change, angle drift, noise or excessive contact resistance may already violate function.
Record location and lot
Link every sample to material lot, process state and initial data. Preserve fracture and fixture information to separate design, manufacturing and assembly causes.
References
This article is informed by public standards catalogues and industry engineering resources. Project values should be confirmed by drawings, material certificates and sample validation.