Mechanical responses failure analysis

Surface analysis has made enormous contributions to the field of adhesion science. It enabled investigators to probe fundamental aspects of adhesion such as the composition of anodic oxides on metals, the surface composition of polymers that have been pretreated by etching, the nature of reactions occurring at the interface between a primer and a substrate or between a primer and an adhesive, and the orientation of molecules adsorbed onto substrates. Surface analysis has also enabled adhesion scientists to determine the mechanisms responsible for failure of adhesive bonds, especially after exposure to aggressive environments. The objective of this chapter is to review the principals of surface analysis techniques including attenuated total reflection (ATR) and reflection-absorption (RAIR) infrared spectroscopy. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) and to present examples of the application of each technique to important problems in adhesion science. 

The next edition of ASCE 41 - ASCE/SEI 41-13 (ASCE 2014) - has just been published and expands the remit of ASCE 41 to include the multitiered seismic assessment approach previously found in ASCE/SEI 31-03 (ASCE 2003). The nonlinear response history analysis procedures have been expanded somewhat, reflecting significantly increased application of this method and the availability of research efforts such as Deierlein et al. 2010 NEHRP Consultants Joint Venture 2010, since the publication of ASCE/SEI 41-06. Nonlinear behavior of force-controlled actions is now permitted to allow explicit modeled of post-failure redistribution following brittle failure. Finally, and importantly for this entry, the unreinforced masonry (URM) wall provisions have been updated major changes are that bed-joint sliding is now considered a deformation-controlled action, while the pier rocking mechanism is now limited to lower axial load ratios and for piers at least 6" in thickness. 

Visual examination, digital photography, and microscopic techniques (optic, electronic, and atomic force microscopies) are powerful tools for collecting valuable information on the mechanisms responsible of the ultimate failure of the specimens under analysis. 

The Control plug supports the 12 absorber drive mechanisms, sleeves which house thermocouples for measurement of outlet temperature of each fuel subassembly and three selector valves with sodium sampling from each fuel SA for failed fuel location. Use of bellows has been avoided for CSRDM to extend the life of the mechanisms and to enhance reactor availability, as bellows failure has been responsible for replacement of CRDMs in reactors using this concept. V-ring seals are used between the stationary sheath and mobile assembly of CSRDM. The core thermocouples are located at a fixed distance of 90 mm from the top of the SA during reactor operation and no Core Cover Plate Mechanism (CCPM) is provided as in FBTR. Thermohydraulic analysis indicates that the thermocouples are immersed in their respective streams at all power levels thereby ensuring adequacy of temperature measurement. 

Rehability analysis using the Strength-Stress method requires the definition of the performance function G(G = R-S), which characterizes the operating state of a structure. With complex structures, this function does not necessarily take an exphcit form. Calculating failure probabihty therefore means resorting to predefined approximations of performance function G using, for example, the Response Surface Method. Taking time into accoimt in mechanical reliability allows us to assess the failure probabihty at time f in the hfe of a structure or component. This... 

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