Bending-mode failure

Fig. 10.8. Located AE sources in reinforced concrete beams of (a) bending-mode failure and (b) shear-mode failure.

Concerning the reinforced concrete, two t) es of failure modes are known. One is referred to as bending-mode failure. In the beginning of loading, tensile cracks are nucleated at the bottom of the moment span (a portion between loading points in the case of two-point loading) due to bending... 

In the present study the reliabihty assessment is illustrated for the bending moment failure mode only. To satisfy requirements of the Eurocodes, deterministic rehabdity condition is written as follows ... 

As explained previously by Lu et al. [215], there are standard testing methods and equipment that can be employed for reinforced aerogel materiak such as polymer cross-linked ones (X-aerogek), although their standard mechanical characterization does not exist. Flexural tests are carried out in three-point bending mode, normally leading to failure imder tensile bending stresses in... 

Shih, G.C. and Ebert, L.J. (1986). Interface strength effects on the compressive-flexure/shear failure mode transition of composites subjected to four-point bending. J. Mater. Sci. 21, 3957-3%5. 

Block polymer B differs substantially in its failure characteristics from BP A polycarbonate. For the block polymer a mixed failure mode predominates in three-point bend tests of notched specimens from —100°-90°C. In the mixed mode craze breakdown and plane strain fracture occur first inside the specimen subsequently shear failure occurs in the surface regions of the specimen. Shear lips (11) are formed as a result. Shear lips are also found on the notched Izod impact fracture surfaces of block polymer B, implying that the same mixed mode of failure occurs under high speed loading conditions. 

In all the S4/0 specimens the delamination crack stops after only 5 mm of propagation in the pinned block. The failure mode then changes from delamination crack propagation to a bending failure of the arms. The toughness at the time of failure is 7000 J/m. TTie calculated bending stress in the beam is (Tb=l lOOMPa. The local curvature leads to a compressive failure strain in the outside layers of 1.3%. 

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