Design failure analysis

Mechanical Design Failure Analysis With Failure Analysis System Software for the IBM PC, David G. Ullman... 

Architectural rendering and analysis of the system Software architecture refers to a structured conceptual representation of a software system. Software architectural rendering of a system serves as a framework from which more detailed design activities can be developed. Software architecture first defines top hierarchical or modular components of the system that are sufficient to represent the system. The details of each modular component could then be addressed in further design. Failure analysis could start at the top. After analysis at the first level, modifications are suggested and implemented. After this level, work is complete, and then one can proceed to the next level down in this way the entire system can be analyzed. With this, discussions on FMEA for E/E/PE is concluded to explore the possibility of automating FMEA. 

Chapter 7 (ROICs and FPAs) describes the larger arrays often used in imaging applications. The chapter was written by John Vampola of Raytheon Vision Systems. John has participated extensively in the design, failure analysis, and applications of these devices. 

Fault Tree Analysis. Fault trees represent a deductive approach to determining the causes contributing to a designated failure. The approach begins with the definition of a top or undesired event, and branches backward through intermediate events until the top event is defined in terms of basic events. A basic event is an event for which further development would not be useful for the purpose at hand. For example, for a quantitative fault tree, if a frequency or probabiUty for a failure can be deterrnined without further development of the failure logic, then there is no point to further development, and the event is regarded as basic. 

Failure Mode and Effects Analysis. The system design activity usually emphasizes the attainment of performance objectives in a timely and cost-efficient fashion. The failure mode and effects analysis (FMEA) procedure considers the system from a failure point of view to determine how the product might fail. The terms design failure mode and effects analysis (DFMEA) and failure mode effects and criticaUty analysis (EMECA) also are used. This EMEA technique is used to identify and eliminate potential failure modes early in the design cycle, and its success is well documented (3,4). 

Electrical engineering Equipment design Expert systems Extraction Failure analysis Flow analysis Safety... 

Reliable thermodynamic data are essential for the accurate design or analysis of distillation columns. Failure of equipment to perform at specified levels is often attributable, at least in part, to the lack of such data. 

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. 

We go next to the analysis and failure analysis block in Figure 7-11. That is, we consider the initial configuration with a particular material or materials. Then, for the prescribed loads, we perform a set of structural analyses to get the various structural response parameters like stresses, displacements, buckling loads, natural frequencies, etc. Those analyses are all deterministic processes. That is, within the limits of accuracy of the available analysis techniques, we are able to predict a specific set of responses for a particular structural configuration. We must know how a particular structural configuration behaves so we can compare the actual behavior with the desired behavior, i.e., with the design requirements. 

Finally, failure analysis is the process of comparing actual performance with the desired performance. Thus, failure analysis is a nontrivial part of the structural design process. Facets of failure analysis including what failure means for a structure are addressed in Section 7.6 on Design Requirements and Design Failure Criteria. 

Failure analysis statistics have consistently shown that many machinery components failures can be directly attributed the equipment being operated outside of design parameters or unintended conditions. Most failure analysis and trouble-shooting activities are usually post-mortem and commence after installation and start-up of the equipment. The maintenance phase is now in motion, and failure analysis and trouble-shooting is now an integral part of that phase. 

Develop final Perform structural design of analysis of component acceptable accuracy Determine structural response—stresses, support reactions, deflections, and stability—based on a structural analysis of acceptable accuracy. Determine acceptable accuracy based on economic value of component, consequences of failure, state-of-the-art capability in stress and stability analysis, margin of safety, knowledge about loads and materials properties, conservatism of loads, provisions for further evaluation by prototype testing... 

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. 

Several catastrophic fire incidents in the petroleum industry have been the result of the facility firewater pumps being directly affected by the initial effects of the incident. The cause of these impacts has been mainly due to the siting of the fire pumps in vulnerable locations without adequate protection measures from the probable incident and the unavailability or provision of other backup water sources. A single point failure analysis of firewater distribution systems is an effective analysis that can be performed to identify where design deficiencies may exist. For all high risk locations, fire water supplies should be available from several remotely located sources that are totally independent of each and utility systems which are required for support. 

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