Failure analysis examples

Examples of engineering actions include design, qualification, and failure analysis. Examples of operations actions include surveillance, carrying out operational procedures within specified limits, and performing environmental measurements. 

Infrared Spectroscopy. IR is not a very sensitive method, so that it usually cannot detect and identify trace materials. Since it does not separate compounds in a mixture, spectral interpretation may not be conclusive. In many cases, however, IR can be usefid in failure analysis. Examples follow. 

The causes of low pressure, for example, could be cither hydraulic or mechanical. In many cases of failure analysis, asking Wliy. and Wliat and answering those questions, until you can no longer ask why , will almost always get you to the answer. If all evidence leads to a mechanical reason for the failure, the problem is probably maintenance induced. If the evidence leads to a hydraulic reason for the failure, the problem is eitJier operations or design induced. In cases where the reason for failure was not determined, a more extensive analysis is necessary. The additional analysis is recommended to take advantage of the pump supplier experience in identifying the root cause. 

Laser ionization mass spectrometry or laser microprobing (LIMS) is a microanalyt-ical technique used to rapidly characterize the elemental and, sometimes, molecular composition of materials. It is based on the ability of short high-power laser pulses (-10 ns) to produce ions from solids. The ions formed in these brief pulses are analyzed using a time-of-flight mass spectrometer. The quasi-simultaneous collection of all ion masses allows the survey analysis of unknown materials. The main applications of LIMS are in failure analysis, where chemical differences between a contaminated sample and a control need to be rapidly assessed. The ability to focus the laser beam to a diameter of approximately 1 mm permits the application of this technique to the characterization of small features, for example, in integrated circuits. The LIMS detection limits for many elements are close to 10 at/cm, which makes this technique considerably more sensitive than other survey microan-alytical techniques, such as Auger Electron Spectroscopy (AES) or Electron Probe Microanalysis (EPMA). Additionally, LIMS can be used to analyze insulating sam-... 

Most applications of LIMS are in failure analysis. A typical microanalytical failure analysis problem, for example, may involve determinating the cause of corrosion in a metallization line of an integrated circuit. One can achieve this by performing an elemental survey analysis of the corroded region. Since it is not always known which elements are normal constituents of the material in question and which are truly contaminants, the vast majority of these analyses are performed by comparing the elemental make-up of the defective region to that of a control region. The com-... 

The process of analyzing designs includes the modes of failure analysis. At an early stage the designer should try to anticipate how and where a design is most likely to fail. A few examples of potential problems due to loading conditions on products are reviewed. 

A comprehensive review of compositional and failure analysis of polymers, which includes many further examples of analysis of contaminants, inclusions, chemical attack, degradation, etc., was published in 2000 [2], It includes details on methodologies, sampling, and sample preparation, and microscopy, infrared spectroscopy, and thermal analysis techniques. 

A surface analysis technique used in bonding failure analysis, for example. 

Metals. In forensic practice, metallic objects are investigated primarily by the firearm and toolmark examiner typical examples are weapons, bullets, cartridge casings and hand tools. Metals are also encountered in cases of failure analysis (frac-... 

Finite element modeling is also useful in failure analysis. The method has been successfully applied in failure analysis. An example involving the stressed condition with maximum stress concentration in cloverleaf radius is shown in Figure 2.29. Another example of finite element modeling applied to distorted transformer housing due to internal overpressurization has been cited in Figure 2.17. 

Mass spectrometry has become more useful In the support of electronic development and manufacturing processes. Fourier transform mass spectrometry, the latest advance in this analytical method, Is another step forward in versatility, sensitivity and reproducibility in analytical characterization, qualification and quantification of raw materials and contaminants as used in electronic devices. A review will be provided of basic instrument hardware and interfacing, significant operating parameters and limitations, and special inlet systems. Emphasis will be placed on material evaluation, process control and failure analysis. Data handling will be reviewed using appropriate examples encountered in material and failure analysis. 

In this section, examples of failure analysis are discussed where the methodology and analytic techniques, described earlier in this chapter, have been applied to some actual cases. Certain aspects of these actual cases have been altered to insure confidentiality of the sources. 

ANALYSIS DOCUMENTATION. PrHA report documentation should include the PrHA worksheets, checklists, logic diagrams, human reliability analyses, and any other analysis made to better understand the scenarios. The PSM Rule requires that human factors that impact scenarios as cause or protection be expanded to analyze the basic cause of errors or response failures. For example, a cause may identify that an operator can turn the wrong valve to initiate an accident. The PSM Rule requires that basic causes also be identified. For example, valve is not labeled the operator has not been trained on the operation or the operator forgot the step. There may be more than one basic cause. (See also Section 3.2, paragraph on Human Factors.)... 

Very often a great deal of dimensional information can be found by means of microscopy. which is such an important subject in its own right as to be in no way considered here as a branch of physical testing. For example, one would expect to employ a microscope to determine the thickness of a wax film on the surface of a rubber or to study the geometry of fibers or thin film, and much failure analysis involves detailed optical e.xam-ination. There are inevitably a great number of special circumstances connected with polymers where an unusual type of dimensional measurement is required, such as the footprint area of tires or the crack length in fracture tests, A number of methods of interest will be mentioned in later chapters in conjunction with particular physical tests. 

Adhesives are a very diverse and complex group of materials. They can manifest themselves in many shapes and forms—they can be viscous liquids, powders, or cured products. Analysis or characterization is an essential step in working with adhesives. As a rule, such efforts are directed toward a specific purpose that may focus on structural determination, curing reaction, size of the molecule, material design at a molecular level, process control, or failure analysis. In this chapter we provide a general review of several physical methods frequently used for analysis of adhesives. In view of the prolific literature on the subject as well as the space constraints, it is not intended to give a comprehensive treatment of the theory and experimental aspects. The examples chosen for this review are illustrative and not exhaustive. 

Use of fracture mechanics test methods for failure analysis of FRP composite elements is feasible, but to the best knowledge of the author, no examples of this have been published. The challenge here is mainly the preparation of suitable test specimens from structural elements and the creation of the starter cracks. ISO 15024 does provide some information on mode I starter crack preparation for nonstandard specimens in an informative appendix (B.8, Guidelines for wedge precracking ), and that procedure can be adapted for other specimen geometries. 

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