Aerospace Fatigue & Fracture Testing
Design fatigue and fracture studies around load history, specimen pedigree and engineering decisions.
Fatigue life, crack-growth resistance and fracture toughness are different outputs. Choose coupon, joint, subcomponent or full-component work according to the decision and available validation evidence. A coupon S–N curve cannot automatically establish assembly life, particularly where joints, residual stress and service spectra dominate.
State material lot, product form, processing, orientation, surface finish, machining and environmental conditioning. Provide load control mode, stress or strain levels, load ratio, frequency, waveform, temperature and runout/failure definitions. Representative service spectra may need a different design from constant-amplitude screening.
ASTM E466 addresses force-controlled constant-amplitude axial fatigue of metallic materials; ASTM E647 concerns fatigue crack-growth rates. Applicability, specimen validity and the required revision must be confirmed against the material and customer programme. Plan replicates and statistical treatment with the responsible engineer rather than assuming a universal sample count.
Request setup and calibration records, time histories, specimen failures and runouts, deviations and uncertainty or scatter treatment where appropriate. Preserve fracture surfaces for follow-up fractography. Clarify whether the engagement provides test data only or engineering interpretation; design allowables and airworthiness decisions remain with the responsible authority.