Gerald T. Jeka - Failure Analysis and Project Work History Images

 

FAILURE ANALYSIS GUIDELINES

 

Four Basic Failure Mechanisms: Design, Material, Processing and Environmental

 

Failure Analysis Protocol:

  1. Gathering of Background Information and Selection of Samples
  2. Review of Safety Considerations
  3. Establishment of Record Keeping
  4. Macroscopic (Visual) Examination and Analysis
  5. Identification, Preservation and Cleaning of Samples
  6. Microscopic Examination and Fractography
  7. Determination of Failure Mechanism (“How it failed”)
  8. Mechanical Testing
  9. Stress Analysis (including Fracture Mechanics and FEA)
  10. Chemical Analysis
  11. Testing Under Simulated Service Conditions
  12. Analysis of Evidence and Formulations of Conclusions (“Why it failed”)

 

 

After data collection, visual inspection  and photographic documentation, optical microscopy is often one of the most important steps to a failure analysis investigation.

 

 

Residual stress measurement made on a glass-filled polymeric injection molded part.

 

 

 

 

Slow crack growth fracture origin adjacent to a metal insert on a nylon housing  was the result of environmental stress-cracking.

 

Environmental stress-cracking revealed on the inside of a medical device with the aid of a red-colored dye penetrant.

 

Bottle cap closure fractured cross-section with failure origins     located in the inner "steps".

 

Cross-sectioned black powdercoated metal automotive trim panel reveals a large void formed at the subsurface epoxy layer extending into the powdercoat layer above. The surface "pinhole" defect is shown above.

 

Fracture surface of a glass-fiber reinforced nylon filter housing with good adhesion of the fibers to the polymer matrix.

 

Scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) is an extremely valuable tool for materials evaluation.  SEM/EDS microscopy is particularly useful for fractographic examination, elemental mapping and phase determination, contaminant analysis, corrosion analysis, topographic analysis and particle size analysis.

 

 

SEM micrograph of a slow crack growth fracture origin  on a PC blend material due to enivronmental stress-cracking caused by the cutting solution in the presence of molded-in stress.

 

 

 

Fatigue sample fracture origin on a PC blend material.

 

Dendritic crystalline formations due to residual sodium on a titanium catalyst surface, SEM micrograph.

 

SEM micrograph of Iron-oxide scale deposited on a titanium catalyst.

 

 

 

 Cross-sectioned sample of Iron-oxide on a titanium substrate.

 

 

Side view of a crack on a screw boss stanchion that failed due to marginal material that was degraded during processing in conjunction with stress from assembly torque and thermal cycling during quality testing.

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