Failure Flexibility

Necessary redundancy to ensure no single point failure Flexible allocation of safety channels and controls [10]... 

The hardware and software used to implement LIMS systems must be vahdated. Computers and networks need to be examined for potential impact of component failure on LIMS data. Security concerns regarding control of access to LIMS information must be addressed. Software, operating systems, and database management systems used in the implementation of LIMS systems must be vahdated to protect against data cormption and loss. Mechanisms for fault-tolerant operation and LIMS data backup and restoration should be documented and tested. One approach to vahdation of LIMS hardware and software is to choose vendors whose products are precertified however, the ultimate responsibihty for vahdation remains with the user. Vahdating the LIMS system s operation involves a substantial amount of work, and an adequate vahdation infrastmcture is a prerequisite for the constmction of a dependable and flexible LIMS system. 

Maximum Strain. Strain in enamels that leads to failure is on the order of 0.002—0.003 cm/cm. Thinner enamels having higher residual compressive stresses are more flexible and can be strained to a greater degree. 

Flexible Metal Hose Deeply corrugated thin brass, bronze, Monel, aluminum, and steel tubes are covered with flexible braided-wire jackets to form flexible metal hose. Both tube and braid are brazed or welded to pipe-thread, union, or flanged ends. Failures are often the result of corrosion of the braided-wire jacket or of a poor... 

Leakage or failure of flexible connections between centrifuge and receiving container. 

Failure of compo- Ensure all system components, including flexible nents in connectors are rated for maximum feasible subatmospheric vacuum conditions pressure convey-, Ensure adequate pressure control system and ing operations. back-up (e.g., vacuum relief devices) API 2000 CCPS G-3 CCPS G-11 CCPS G-22 CCPS G-29 CCPS G-3 9... 

We previously encountered failure modes and effects (FMEA) and failure modes effects and criticality analysis (FMECA) as qualitative methods for accident analysis. These tabular methods for reliability analysis may be made quantitative by associating failure rates with the parts in a systems model to estimate the system reliability. FMEA/FMECA may be applied in design or operational phases (ANSI/IEEE Std 352-1975, MIL-STD-1543 and MIL-STD-1629A). Typical headings in the F.Mld. A identify the system and component under analysis, failure modes, the ef fect i>f failure, an estimale of how critical apart is, the estimated probability of the failure, mitigaturs and IHissihiy die support systems. The style and contents of a FMEA are flexible and depend upon the. ilitcLiives of the analyst. 

The selection of a suitable matrix for a composite material involves many factors, and is especially important because the matrix is usually the weak and flexible link in all properties of a two-phase composite material. The matrix selection factors include ability of the matrix to wet the fiber (which affects the fiber-matrix interface strength), ease of processing, resulting laminate quality, and the temperature limit to which the matrix can be subjected. Other performance-related factors include strain-to-failure, environmental resistance, density, and cost. 

Net-tension failures can be avoided or delayed by increased joint flexibility to spread the load transfer over several lines of bolts. Composite materials are generally more brittle than conventional metals, so loads are not easily redistributed around a stress concentration such as a bolt hole. Simultaneously, shear-lag effects caused by discontinuous fibers lead to difficult design problems around bolt holes. A possible solution is to put a relatively ductile composite material such as S-glass-epoxy in a strip of several times the bolt diameter in line with the bolt rows. This approach is called the softening-strip concept, and was addressed in Section 6.4. 

Quality Management systems have demonstrated their effectiveness in providing efficient, flexible management processes. However, in many instances they have failed to deliver their promises in full and in some cases have failed completely. These failures have been ascribed to cultural obstacles that were not identified during the design process. In a recent survey of 350 senior executives Arthur D. Little, Inc. found that 68 percent of the companies reported unanticipated problems with their change process. 

Real-time access to the data base is possible through a data base management system. In addition to safety-related system data, data for interfacing (auxiliary) system components are also available. The data base management system provides in-depth flexibility for generation of specific output reports. Although access has been limited to members of the Swedish Utility Consortium and the Swedish Power Board Directorate, a Reliability Data Book is available with generic failure rates based primarily on this data base. 

Most of the failure modes associated with jackshafts and spindles are the result of lubrication problems or fatigue failure resulting from overloading. However, the actual failure mode generally depends on the configuration of the flexible drive. 

Repeated twisting of the spindle s tube or the solid shaft used in jackshafts results in a reduction in the flexible drive s stiffness. When this occurs, the drive loses some of its ability to absorb torsional transients. As a result, damage may result to the driven unit. Unfortunately, the limits of single-channel, frequency-domain data acquisition prevents accurate measurement of this failure mode. Most of the abnormal vibration that results from fatigue occurs in the relatively brief time interval associated with startup, when radical speed changes occur, or during shutdown of the machine-train. As a result, this type of data acquisition and analysis cannot adequately capture these... 

Flexibility The normal anodic film begins to crack if subjected to an extension exceeding about 0 - 5%. Thinner films up to 5 nm in thickness appear to withstand a greater degree of deformation without obvious failure, and are often used for dyed coatings on continuously anodised strip from which... 

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