Failure Analysis

Materials fail for different reasons, but they fracture by four principal modes: fatigue, cleavage, dimple rupture, and decohesive rupture. Each of these modes has its own characteristic fracture appearance.

1. 疲劳断裂是由于重复loading. Crack(s) initiates in Stage I, propagates in Stage II, and reaches catastrophic fracture including separation in Stage III. Fatigue striations observed generally in high cycle fatigue align perpendicular to crack propagation direction.
2. Cleavage is a low-energy fracture that is completely flat and featureless. River patterns, feather markings, and chevron patterns are some of the features observed in cleavage mode of fracture.
3. Dimple rupture is the mode of fracture when an overload is the principal cause of failure. Microvoid coalescence is the characteristic feature observed in dimple rupture.
4. Decohesive rupture occurs with little plastic deformation and involves weakening of the atomic bonds. Hydrogen embrittlement, stress corrosion cracking, and creep are some of the examples of decohesive rupture.

Element's team of Engaged Experts employ a wide variety of fractographic testing methods to determine the failure causes of parts, products, and engineering structures.

A material's composition affects everything about it—how long it lasts, how strong or flexible it is, how it’s packaged, etc. Investigative Chemistry is based on the idea that materials questions can be answered by examining the processes, components and chemical reactions involved.

Element’s investigative chemists possess a unique range of experience in consulting, analytical testing, and industrial chemistry. Whether routine QA/QC assistance, material verification, or elemental analysis—or nonroutine projects such as product deformulation, identification of unknown materials, or the analysis of a failed part or product—we are prepared to work with you to explore solutions. Element serves the testing needs of all types of industries and government agencies.

Element performs testing and evaluation using the following techniques and onsite specialized equipment:

• 傅里叶反式form Infrared Spectroscopy (FTIR)
• Energy Dispersive X-Ray Spectrometry (EDS)
• Gas Chromatography/Mass Selective Detection (GC/MSD)
• 扫描电子显微镜(SEM)
• Optical Emission Spectrometry (OES)
• Differential Scanning Calorimetry (DSC)

Mysterious stains or discolorations, unidentified residues or deposits, or evidence of corrosion on the surface of a part—these are often difficult and costly problems to solve.

Element residue analysis experts are trained in techniques that can help you determine the nature of the beast and get to the bottom of unknown substances that can have a detrimental effect on your parts or products. Our Engaged Experts use a combination of analysis techniques to characterize various types of residues. SEM/EDS (Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy) analysis is used to determine the elemental composition of the residue, with XRD (X-Ray Diffraction) sometimes used to identify specific compounds present. FTIR (Fourier Transform Infrared Spectroscopy) is also sometimes used when residues appear to exhibit high levels of carbon or other low energy elements, or are too thin to accurately analyze with the SEM/EDS system.

When a more in-depth analysis is requested or required, a combination of stereomicroscopy, SEM analysis and metallurgical examination is used to characterize the residue as being on top of the surface (a deposit or stain) or being beneath the surface (a corrosion product or inclusion within material).

Polymeric materials such as elastomers, thermoplastics, composites are widely used in oilfield equipment deployed by the Oil & Gas majors across the world.

In the case of elastomeric (rubber) seals, exposure in service to aggressive treatment chemicals and/or elevated temperatures and pressures can chemically and/or mechanically degrade the parts, resulting in irreversible change, performance deterioration and eventual functional failure of the component.The challenge is therefore to determine the root cause of failure, so that preventative and corrective actions can be implemented to ensure that it does not happen again. With over 100 years’ experience in the global Oil & Gas sector, Element has significant failure analysis experience with non-metallic components whether they are employed in upstream, midstream or downstream applications. Element has been involved in providing failure analysis services on:

• Pumps and valves (ball, butterfly, pressure relief, bonnet, flow control)
• Hoses (bunker, choke/kill, sampling, diesel & potable water transfer, umbilical)
• Drilling and production equipment (compressors, plate heat exchangers, packers, BOP,sub seaand surface test trees, liner hangers, well tractors, swivels)
• Pipelines for natural gas and chemical processing (coatings, liners)
• Miscellaneous (vent plug, burst disc, pulsation dampener, hammer lug union, pig trap door, dump pit liner,harborfender, flange gaskets)

Our proven failure analysis approach is to develop a thorough understanding of the failed component’s service environment by working with our clients to gather relevant data from the field, such as

• Component location and function (engineering drawings)
• Material type and grade (data sheet, part label)
• Service conditions (fluids, temperature, pressure, duration)
• Design conditions (temperature, pressure, static/dynamic)
• Previous issues with this or similar components

Our tried and tested failure analysis techniques include:

• Forensic inspection and cataloging of the damaged component (microscopes, SEM)
• Component measurement (dimensions)
• Material characterization (hardness, density, mechanical)
• Material/fluid type analysis (FTIR, NMR, GC-MS, TGA, DSC, XRD)
• Material-fluid compatibility assessment (fluid exposure vessels; ovens)
• Machining to facilitate inspection and extract test specimens (lathes, saws, CNC)

Legal and insurance firms need expert witnesses to provide testimony with a high level of service, precision and expertise. Through our team of Engaged Experts, Element offers materials science and engineering litigation services to a wide range of industries, including aerospace, product manufacturing, biomedical and medical devices, automotive, oil & gas, construction, and more.

Element scientists and engineers possess many years of experience, advanced degrees, and certifications in many sub disciplines including Materials Science & Engineering, Mechanical Engineering, Chemical Engineering, Polymer Science, Metallurgical Engineering, Welding, and Corrosion. To support of our legal and insurance investigations, our laboratories use highly advanced analytical instrumentation, such as state-of-the-art Scanning Electron Microscopes (SEM) equipped with ultrathin window Energy Dispersive X-ray Spectroscopy (EDS) systems, Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared Spectroscopy (FTIR) for molecular analysis.We have established chain-of-evidence procedures and locked legal storage to properly handle evidence in accordance with established standards (e.g., ASTM standard practices E860, E1188, and E1492).

We specialize in:

• Detecting defects or evidence of abuse
• Determining physical, mechanical or chemical properties of materials
• Assisting with subrogation claims
• Developing precision evidence analysis protocols
• Determining specification compliance
• Evaluating patent infringement
• Responding to Daubert challenge
• Delivering detailed and convincing deposition and trial testimony
• Advanced instrumentation and qualified expertise

We serve individual or groups of legal and insurance customers, including joint plaintiff and defendant investigations for litigating parties. Our engineers also coordinate testing with other outside engineering expert, testing, and support firms.