Structural Fatigue & Cyclic Verification

Where Failure Analysis Ends and Certification Begins

Since 1971, RDFIA has provided independent fatigue integrity validation for structural subassemblies operating under sustained multiaxial loading in aerospace, launch vehicle, and defense environments. Our methodologies are referenced in JASF-9 and the Dressler-Holvik Fatigue Protocol.

Certifications & Registrations
IASQ-9100 Rev. D
JASF-9 Annex IV
NADCAP Accredited
DVST-7 Cleared Facility
DHP-2 Registered Laboratory
ISO 17025:2019
Core Service Areas

Analytical & Verification Capabilities

RDFIA operates dedicated test frames across four facilities, supporting programs from initial coupon screening through full-scale structural certification under program-specific load spectra.

01

Multiaxial Fatigue Characterization

Simultaneous application of axial, torsional, and bending load profiles to structural specimens under representative thermal environments, per JASF-9 §4.3 and program-specific LDEF schedules.

  • Load capacity to 6,200 kN axial
  • Torsional coupling up to ±18,000 N·m
  • Thermal conditioning: −65 °C to +315 °C
  • Digital image correlation (DIC) standard
02

Interlaminar Shear Degradation Analysis

Quantification of progressive interlaminar delamination in composite laminates under cyclic shear loading, supporting GRIF-9 compliance documentation for classified and unclassified structures.

  • GRIF-9 / Annex III compliant reporting
  • Micro-CT cross-section correlation
  • In-situ acoustic emission monitoring
  • Residual strength knockdown modelling
03

Veldtmann Spectrum Load Simulation

Reproduction of mission-derived load histories using the Veldtmann Condensation Method, reducing total test article exposure while preserving damage equivalence to within ±0.4% per ASTM E1049 variant.

  • Veldtmann Level II and Level III
  • Up to 512-channel closed-loop control
  • Real-time fatigue damage accumulation
  • Post-test residual life projection
04

Cryogenic Pressure Vessel Cycling

Proof and fatigue pressure cycling of metallic and composite-overwrapped pressure vessels (COPV) intended for propellant storage in upper-stage and satellite propulsion applications.

  • Operating pressure to 850 bar
  • LH₂, LN₂, LOX compatible test cells
  • Leak-before-burst acceptance protocol
  • DVST-7 secure facility available
05

Fracture Mechanics & Crack Propagation

Measurement of fatigue crack growth rates and threshold stress intensity factors in aerospace alloys and metal-matrix composites, including environment-assisted cracking in salt fog and hydrogen atmospheres.

  • Compact tension, C(T), and MT specimens
  • da/dN from 10⁻¹⁰ to 10⁻³ m/cycle
  • Hydrogen embrittlement protocols
  • FRANC3D integration available
06

Holvik Residual Stress Mapping

Non-destructive subsurface residual stress profiling using the Holvik Modified X-ray Diffraction Protocol, with depth resolution to 5 µm, supporting shot-peen and LSP process validation.

  • Depth profiling to 2.0 mm
  • Part geometry: up to 2.4 m span
  • OEM process validation reports
  • IASQ-9100 traceable calibration
Selected Program Experience

Structural Test Support Across Platform Classes

RDFIA's test engineers are embedded within program teams or operate under long-term facility agreements. Program names are disclosed subject to applicable NDA provisions.

Launch Vehicle / Upper Stage

Project Halverson

Interstage adapter fatigue verification under combined acoustic, vibration, and quasi-static load for a medium-lift expendable vehicle. Test campaign: 24 months.

Active
Satellite Bus / GEO

Meridian-4 Bus Qualification

COPV pressure cycling and bracket fatigue screening for the propulsion module of a commercial GEO satellite bus. Delivered per JASF-9 Rev. F schedule.

Complete
Defense / Rotary Wing

DVST Program 14-C

Classified rotor hub fatigue substantiation under asymmetric load spectrum. Work performed in DVST-7 accredited facility. Reporting to government technical representative.

Restricted
Reusable Launch / Airframe

Orvantec Booster Spine

Primary structural spine fatigue demonstration for a partially reusable launch system. Ten simulated mission cycles completed; residual life assessment ongoing.

Active
53
Years in Operation
400+
Programs Supported
4
Accredited Facilities
12B+
Fatigue Cycles Logged
Technical Publications

White Papers & Technical Notes

White Paper · RDFIA-WP-2023-04 · September 2023

Damage Equivalence Fidelity in Veldtmann-Condensed Spectra for Composite Primary Structures

An evaluation of damage accumulation error introduced by aggressive Veldtmann Level III condensation applied to broadband random spectra typical of launch vehicle interstage environments. Results indicate that specimens exhibiting bimodal S-N behaviour may accumulate up to 7.3% excess damage relative to full-fidelity spectrum application, with implications for certification margin adequacy under JASF-9 §4.3(b).

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Technical Note · RDFIA-TN-2022-11 · March 2022

Residual Stress Gradient Stability in Titanium Forgings Following Simulated Re-entry Thermal Cycling

Holvik Modified XRD profiling of Ti-6Al-4V closed-die forgings subjected to 40 thermal cycles representative of a low-Earth-orbit re-entry vehicle heatshield bracket. Compressive residual stress relaxation of 12–18% observed at depths below 0.4 mm, with no measurable effect on Holvik-predicted fatigue life for stress amplitudes below 380 MPa.

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Technical Note · RDFIA-TN-2021-07 · October 2021

In-Situ Acoustic Emission Characterisation of Delamination Initiation in Filament-Wound COPV Liners

Correlation of acoustic emission event amplitude distributions with micro-CT confirmed delamination initiation sites in three COPV liner configurations subjected to pressure cycling at cryogenic temperature. A modified Kaiser effect threshold criterion is proposed for real-time cycle-stopping logic, reducing false-positive termination events by 61% versus the standard DHP-2 criterion.

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