Typical Failure Modes

Test title UN Manual of UL 1642 lithium IEEE 1625 lap- IEEE 1725 cell NAVSEAS9310- SAE]2464 HEVandEV 

Hazardous substance monitoring Analysis of electrolyte vapors and airborne volatiles and particulates released during abuse tests 

Mechanical shock 3 ea. 150 g shocks for cells, 50 g shocks for modules and packs 3 ea. 125-175 g shocks 3 ea. 125-175 g shocks 18 ea. 15 ms 25 g shocks = XYZ negative and positive directions X three times  

External Less than 100 Less than Ijess than 

Perform two short circuit tests a hard short ( 5 mS2) and moderate short at a resistance comparable to the test article resistance at25 5°C 

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How do the elastic and inelastic properties and their distribution affect the interphase failure mechanisms/modes What are the typical failure modes How do we define interphase strength (the ultimate property which we use to define at what general loading state the fiber and matrix will separate parallel and perpendicular to the fiber direction) (Mechanics/Materials)... 

Finally, how do the mechanical properties and typical failure modes of a particular interphase microstructure influence stiffness, strength and durability under various conditions (Mechanics)... 

Figure 7.37 Typical failure modes of specimens at temperatures from 20 to 180°C (D, delamination K, kink-band) [22]. (With permission from Elsevier.)...

Typical failure modes to consider in a piece-part FMEA include, but are not limited to. Open, Short, Parameter shifts. Out of adjustment. Dielectric breakdown, Intermittent operation. Inoperative, Spurious operation. Wear, Mechanical failure, Sticking, Loose, Fracture, etc. 

In this chapter, a dose examination has been made of the phenomenon of fracture in ceramics. The macroscopic appearance of fracture and typical failure modes in ceramic materials has been analyzed, fracture mirrors and fracture origins have been identified, and the way in which fracture is intrinsically connected to the microstructure of a ceramic has been outlined. In particular, by detailing stress distributions it has been shown that fracture always starts at a single microstructural flaw, the stability of which can be described with simple linear elastic fracture mechanics. Notably, these features are responsible for the inherently statistical nature of failure in ceramic materials, an understanding of which can provide knowledge of the close corrdation between defect populations and fracture statistics, and of how to devdop materials parameters such as the characteristic strength. 

Figure 5.37 Typical failure modes for different tee joint configurations ...

These mechamisms result in the following typical failure modes ... 

The typical failure modes for the most common PCB surface finishes are listed next. It should be noted that these wetting curves are for PWB s that were not packaged and purposefully exposed to the environment for a worst case scenario. PWB s correctly packaged and stored win last a lot longer in the majority ... 

To ensure consistency in results and to allow for ease of comparison, an industry standard test method has been developed and published jointly by IPC and JEDEC (IPC/JEDEC-9102) This test method outlines in detail the requirements of the monotonic bend test method. The test setup is illustrated in Fig. 59.9. The typical failure modes observed at the solder joint interconnects are shown in Fig. 59.10. 

Failure mode describes how the component can fail. All credible failure modes and their causes should be listed. Since a failure mode may have more than one cause, all probable independent causes for each failure mode should be identified and described. Three failure mode causes are shown in the sample worksheet. Some engineers will create a separate failure cause column tied to each failure mode so that causes are more easily tracked. Here, the two are combined for ease of understanding. Typical failure modes (conditions) that should be considered are... 

Negative ribs have been utilized recently to resolve another issue. In normal applications, the separators have not been the typical failure mode of the battery. As such, there has been an effort to reduce the mass of the separator. This is achieved by reducing the back-web thickness. Over the years the typical back-web has migrated from 300 pm to as low as 150 pm. Even at 150 pm for the back-web thickness, the... 

The bath tub curve generally emerges through superposition of three typical failure modes and is therefore subdivided into the following sections ... 

These cyclic mechanical stresses lead to fatigue or ageing of the concerned materials. Crack formation or wear-out is a typical failure mode that can be observed. These failure modes are common if mechanical components are considered. This does not surprise as the principle failure mechanism is purely on the material mechanical side. 

Mechanical Seals Typical Failure Modes and Their Causes... 

Mechanical seals can fail in many different failure modes due to various causes. Typical failure modes and their corresponding causes for mechanical seals are as follows [4] ... 

List at least 10 typical failure modes of mechanical seals. 

Typical failure modes of these materials are caused by voids between layers, unbonds between layers, impurities or foreign material in the laminar interfaces, and significant irregularities (damage) to the geometric core structure. Criteria for acceptability of each part to be evaluated must be established in terms of minimum size of void to be detected, minimum area of disbond that can be said to constitute a defect, and any other void or disbond characteristic that is deemed significant. To start the program, then, it becomes necessary to use samples of known acceptable and known defective parts. Ideally, the defective samples furnished should include known defects of each classification and the minimum sizes required to be detected and identified. When this isn t possible it becomes necessary to synthesize flaws in the samples to simulate the minimum defects. 

Instrumentation technicians should be included to provide historical accounts of maintenance problems and typical failure modes. They are also valuable in the development of practical recommendations. A representative firom process engineering will be able to comment on the current operating and safety issues associated with the control of the process and approve recommendations that will effect the operations of the unit. For projects that involve the corporate control group, or require approval of the group, a representative should be involved in the HAZOP. Their knowledge of corporate standards such as the use of by-passes on Emergency Shut Down devices or... 

The typical failure mode fotmd in current modem unreinforced masonry composed of regular units and submitted to diagrmal compression load results from the opening of a stair-stepped crack along the unit—mortar interface developing in the direction of load. The crack is developed in the perpendicular directirMi to the tensile stresses, which means that it appears when the tensile stress in masonry is reached. The failure of urueinforced masonry occurs suddenly in very brittle style (see Fig. 12a). 

Nonlinear Analysis and Collapse Simulation Using Serial Computation, Fig. 1 Example of a pushover analysis (a) the load pattern, (b) the capacity curve, and (c) the typical failure mode... 

In the case of reliability analysis for an SIS the following typical failure modes are used. 

Generally, having a nonsolder surface finish to bond a conductive adhesive improves contact resistance [49]. For example, conductive adhesives perform well with palladium-based terminated components. Lead-free board finishes such as nickel/gold and copper/palladium have been evaluated. Failures at the interface between component terminations and conductive adhesives is a typical failure mode observed in durabiUty tests, and also the cause of an increase in electrical resistance. Oxidation and corrosion of Sn-Pb finishes take place at the interface [21]. 

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