Beam specimen

The infonuation that can be extracted from inorganic samples depends mainly on tlie electron beam/specimen interaction and instrumental parameters [1], in contrast to organic and biological materials, where it depends strongly on specimen preparation. 

Fig. 8.11 Effect of beam deflection rate of cantilever beam specimens upon stress-corrosion crack velocity of carbon steel in carbonate-bicarbonate solution...

Corrosion of metals and alloys stress corrosion testing. Part 2 Bent-beam specimens Corrosion of metals and alloys. Part 3 U-bend specimens... 

Ideally the EDS should only receive the X-rays from beam-specimen interaction volume, but it is not possible to prevent radiation from the microscope stage and... 

With the microscope aberrations eliminated, the exit wave function can be directly understood only in terms of the electron beam - specimen interaction. 

I ig. X.ll. Residual stillness a.s a funetion crack length as measured from double cantilever beam specimens after impact damage carbon fiber composites containing (O) unmodified epoxy ( ) rubber-... 

Forced sinusoidal vibration of thin cantilever beam specimen by electrodynamic shaker... 

In addition, this CTF is attenuated by an envelope or damping function, which depends on the coherence of the beam, specimen drift, and other factors (6,71,72). Figure 14.5 shows a few representative CTFs for different amounts of defocus on a normal and a FEG microscope. Thus, for a particular defocus setting of the objective lens, phase contrast in the electron image is positive and maximal only at a few specific spatial frequencies. Contrast is either lower than maximal, completely absent, or it is opposite (inverted or reversed) from that at other frequencies. Hence, as the objective lens is focused, the electron microscopist selectively accentuates image details of a particular size. 

Zehnder, A.T. and Rosakis, A.J. (1990). Dynamic Fracture Initiation and Propagation in 4340 Steel under Impact Loading, International Journal of Fracture, 43, pp. 271-285. Kalthoff, J.F., Beinert, J. and Winkler, S. (1977). Measurements of Dynamic Stress Intensity Factors for Fast Running and Arresting Cracks in Double-Cantilever-Beam Specimens. n Fast Fracture and Crack Arrest, ASTMSTP 627, pp. 161-176, Hahn, G.T. and Kanninen, M.F. (Eds.). American Society for Testing and Materials. 

Standard Mode I Double Cantilever Beam specimens for delamination testing of a unidirectional (UD) IM7/977-2 composite were Z-pinned with two separate blocks of Z-Fiber reinforcement. The reinforced beam configuration was such as to provoke an unstable delamination, propagating between the two Z-pin blocks. Crack resistance curves for these specific geometry specimens of IM7/977-2 indicate that the unstable delamination cracks are arrested by the second Z-pin block, with the crack propagation resistance being dictated primarily by the Z-pinning density within a block. Acoustic emission analysis is used to interpret visual observations and other test data. 

The failure of PC in compression was violent. Compression cylinders would shatter violently and the remaining core of the cylinders had either a cone shape or a near vertical failure surface. Flexural beam specimens also failed in a violent manner as a tensile crack developed in the zone of maximum moment near mid-depth. The specimens were broken into almost two identical pieces and the failure surface was near vertical. The tensile bond strength between the PC overlays and the portland cement concrete substrate was found to be strongly dependent on the type of resin used. In overlay or repair applications, it is usually desirable to have tensile bond failures occurring in the portland cement concrete substrate rather than at the interface between the two materials. 

Electron beam specimen interactions give rise to secondary electrons throughout the total interaction volume but only those that are generated close to the surface will leave the sample and contribute to the signal. The depth is about 1 nm for metals and 10 nm for most insulating (low z) materials. 

Experimental investigations to find the influence of polymer coatings on the strength of concrete and reinforced concrete beams at bend was continued with three series of concrete test specimens (B, Bl, and B3) measuring 3 x 6 x 64 cm, and two series of reinforced concrete beam specimens (BO, BP) measuring 10 x 20 x 160 cm. The polymeric coating compositions were EA-20-100 , PEPA-10 , andesite-100 . 

Brown, B. F. and Beachem, C. D., A Study of the Stress Factor in Corrosion Cracking by use of the Pre-cracked Cantilever Beam Specimen, Corrosion Science, 5 (1965), 745-750. 

Figure 11.6 (a) Schematic of single-edge notched beam specimen (b) Chevron notch specimen. 

Figure 10 Double cantUever beam specimen showing nomenclature and specimen deflection. Copyright 2003 by Taylor Francis Group, LLC...

Figure 13 Comparison of the ERR determined by FEM with G values calculated using the equations from ASTM D-3433 as a function of the ratio of crack length, a, to couble Cantilever beam specimen depth, h. 

The crack initiation energy can readily be determined from a mode I cleavage test using a double cantilever beam specimen [1,2]. This method has been applied to wood-adhesive joints by many researchers [3 17]. The test requires the beam compliance (C), load at crack initiation (P ), crack length at initiation (a), specimen thickness (/), and change in beam compliance = change in displacement of load points/change in... 

In this chapter, an overview of performance characterization of FRP-wood bonded interfaces by conventional and fracture mechanics tests [4- 7] is presented. Modified ASTM standard tests (ASTM D2559 and D905) are first used to study the service performance and shear strength of the bond under moisture and/or mechanical loads, and then a contoured or tapered double cantilever beam specimen [8] is used to evaluate the fracture toughness of bonded interfaces under dry and wet conditions and cyclic loading. 

Finally, the tapered double cantilever beam specimen [8] described in this study can be effectively used to obtain interface mode-I fracture toughness values under various environmental loadings (e.g., under dry and wet conditions [5,14,15]) and cyclic load conditions (fatigue fracture [7]) these data can be implemented in practical applications to assess the potential growth of a delamination crack at the FRP wood interface. 

---