Failure analysis methods

Quinn BJ, Sun CT. A critical evaluation of failure analysis methods for composite laminates. In Proceedings of 10th DoD/NASA/FAA conf on fihrous composites in structural design, vol. V 1994. V21—37. 

Failure analysis methods and manufacturing quahty control and testing have been improved. This effect is potentially more significant in more modem integrated circuits where the level of miniaturization is much greater. 

Faience Failure analysis Fair-Plus Fajans method Falcon... 

Risk-Based Inspection. Inspection programs developed using risk analysis methods are becoming increasingly popular (15,16) (see Hazard ANALYSIS AND RISK ASSESSMENT). In this approach, the frequency and type of in-service inspection (IS I) is determined by the probabiUstic risk assessment (PRA) of the inspection results. Here, the results might be a false acceptance of a part that will fail as well as the false rejection of a part that will not fail. Whether a plant or a consumer product, false acceptance of a defective part could lead to catastrophic failure and considerable cost. Also, the false rejection of parts may lead to unjustified, and sometimes exorbitant, costs of operation (2). Risk is defined as follows ... 

Analysis methods for hydrogen absorbed in the deposit have been described (65), and instmments are commercially available to detect hydrogen in metals. Several working tests have been devised that put plated specimens under strain and measure the time to failure. A method for cadmium-plated work has been described (66) as has a mechanical test method for evaluating treatments on AlSl 4340 Steel (67). Additional information on testing for hydrogen embrittlement is also available (68). 

Local Failure The penetration or perforation of most industrial targets cannot be assessed using theoretical analysis methods, and recourse is made to using one of the many empirical equations. In using the equations, it is essential that the parameters of the empirical equation embrace the conditions of the actual fragment. 

So in this chapter of failure analysis and corrective methods, we decided to consider some problems, symptoms, and remedies particular to PD pumps. We re using two tables. The first table lists the few symptoms that send a PD pump into the shop. These symptoms are mated to another column of possible causes listed in numerical order. The numerical causes are on the second tabic starting with the. source of the problem in the left column and the probable cause/suggested remedy in the right column. As you go through the list, you ll see again that PD pumps and centrifugal pumps have a lot in common. Enjoy. 

The failure determining stresses are also often loeated in loeal regions of the eomponent and are not easily represented by standard stress analysis methods (Sehatz et al., 1974). Loads in two or more axes generally provide the greatest stresses, and should be resolved into prineipal stresses (Ireson et al., 1996). In statie failure theory, the error ean be represented by a eoeffieient of variation, and has been proposed as C =0.02. This margin of error inereases with dynamie models and for statie finite element analysis, the eoeffieient of variation is eited as Q = 0.05 (Smith, 1995 Ullman, 1992). 

Weber, M. A. and Penny, R. K. 1991 Probabilistic Stress Analysis Methods. Stress Analysis and Failure Prevention, DE-Vol. 30, ASME, 21-27. 

The RMDB consists of two mayor sections computer data storage and retrieval system, and backup microfilm data bank file. The computer data storage and retrieval system is used for die standard reliability and maintainability data listing, special calculations, and searches. This data bank system has been established to facilitate remote terminal access compatible with the GIDEP remote terminal programs. The microfilm data bank file is used for storage and distribution of supplier s documents, failure analysis curves, description of methods used in the collection of the data, and additional background information too extensive to include in the computer data bank. 

The analysis methods are similar for all external events probability of the external event, probability of failures, effects of failures on safety systems, and estimating the effects of failures for the workers, public and environment. 

The choice of method from available resources depends largely upon the properties of the material to be analyzed, the basic significance or physical wearing of the measurement, and the purpose for which the information is required. For example, failure to disperse the particles as discrete entities is the biggest single problem in all size analysis methods that depend on individual particulate behavior. With microscopic techniques particles must be dispersed on the slide to permit observation of individual particles, and in sedimentation techniques the material must be suspended in the fluid so that the particles behave as individuals and not as floes. 

Expert opinion is a source, frequently elicited by survey, that is used to obtain information where no or few data are available. For example, in our experience with a multicountry evaluation of health care resource utilization in atrial fibrillation, very few country-specific published data were available on this subject. Thus the decision-analytic model was supplemented with data from a physician expert panel survey to determine initial management approach (rate control vs. cardioversion) first-, second-, and third-line agents doses and durations of therapy type and frequency of studies that would be performed to initiate and monitor therapy type and frequency of adverse events, by body system and the resources used to manage them place of treatment and adverse consequences of lack of atrial fibrillation control and cost of these consequences, for example, stroke, congestive heart failure. This method may also be used in testing the robustness of the analysis [30]. 

Table 4.21. Time Estimates for Using the Failure Mode and Effects Analysis Method...

The comparison of the safety of equipment is not straightforward. It depends on several features of both process and equipment themselves. It can be evaluated from quantitative accident and failure data and from engineering practice and recommendations. Experience has been used for layout recommendations and for the development of safety analysis methods such as the Dow E F Index (Dow, 1987). Statistics contain details, causes and rates of failures of equipment and data on equipment involved in large losses. 

Finite element methods (FEM) are capable of incorporating complex variations in materia stresses in the time varying response. While these methods are widely available, they are quite complex and, in many cases, their use is not warranted due to uncertainties in blast load prediction. The dynamic material properties presented in this section can be used in FEM calculations however, the simplified response limits in the next section may not be suitable. Most FEM codes contain complex failure models which are better indicators of acceptable response. See Chapter 6, Dynamic Analysis Methods, for additional information. 

Our failure risk analysis and opportunity method and iterative software tool, as part of our New Product Process Innovation (NPPI) Tool Library, promotes systematic collaboration and team-oriented engineering thinking when a new pharmaceutical manufacturing system process and/or product are developed. (We call it opportunity method too, since most risks, if not all, offer new opportunities for innovation.) It is based on our generic process failure risk analysis method that could be apphed to literally any process that involves risk—and innovation is a very risky process. 

The trials described so far have commonly shown a lack of usefulness of NKi receptor antagonists in the treatment of pain. But we do not know whether the failure of the selected compounds is a matter of pharmacodynamics (e.g. poor penetration of the blood brain barrier) or a genuine discrepancy between animal and human pain pathophysiology (Urban and Fox, 2000). Hence, animal tests should carefully be chosen whether they are predictive or not, and it would be helpful if a wider range of conditions could be examined (Hill, 2000a). Therefore, new preclinical analysis methods should be developed for a more effective judgement of likely clinical outcomes. 

Failure Modes and Effects Analysis (FMEA) and its variants have been widely used in safety analyses for more than thirty years. With the increase of application domain of software intensive systems there was a natural tendency to extend the use of (originally developed for hardware systems) safety analysis methods to software based systems. 

True method development calls upon the technical expertise of the analytical department and more specifically the project analytical chemist to assess the nature of the chemical entity under investigation and the matrix in which it is present. Success or failure in method development is directly attributable to the analyst s overall technical competence and breadth of knowledge in various analytical techniques. Technically challenging analysis problems are usually handled by more senior members of the laboratory staff or those possessing advanced education and training. 

M. Ortiz et al A finite element method for localized failure analysis. Comp. Methods Appl. Mech. Eng. 61, 189-214 (1987)... 

Failure rates for both equipment and peoples responses are assigned and the frequency and severity of a TOP Event can be calculated. Should the risk be found to be unacceptable, additional process safety hardware or additional procedures can be recommended. Then, calculations can be made to determine the benefits of the additional hardware or procedures. The Fault Tree Analysis method of evaluation is very sophisticated and a detailed explanation is beyond the scope of this book. 

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