Monotonic loading

It is envisaged that the degradation of the frictional interface properties and the corresponding increase in the relative displacements eventually lead to debond crack growth once the debond criterion is satisfied. The debond criterion based on the energy balance theory given by Eq. (4,35) under monotonic loading can be rewritten as... 

Beaumont P.W.R. and Anstice P.D. (1980). A failure analysis of the micro-mechanisms of fracture of carbon fiber and glass fiber composites in monotonic loading. J. Mater. Sci. 15, 2691-2635. 

Figure 10.1 Time-temperature map. Shape of main boundaries for linear or network polymers. (I) Glassy brittle domain B, ductile-brittle transition. (II) Glassy ductile domain G, glass transition. (Ill) Rubbery domain. The location of the boundaries depends on the polymer structure but their shape is always the same. Typical limits for coordinates are 0-700 K for temperature and 10-3 s. (fast impact) to 1010 s e.g., 30 years static loading in civil engineering or building structures. Fpr dynamic loading, t would be the reciprocal of frequency. For monotone loading, it could be the reciprocal of strain rate s = dl/ Idt.

The approach used to simulate Mode I cracking under monotonic loading is to define tractions [Pg.38]

What are the changes that occur in the microstructure of a material in the first cycle The earlier discussion of the microstructural damage that occurs during monotonic loading (Section 6.2.2) provides the insight needed to answer... 

We first briefly review the effects of M on physical properties under monotonic loading conditions. Some properties, such as density and low temperature dynamic mechanical behavior, are essentially unaffected by changes in molecular weight. Other properties, such as the glass transition temperature, T, and the tensile strength, increase appreciably with M in the low molecular weight region but tend to approach an asymptotic value as M is further increased. Fox and Flory have shown that for PS the dependence of T on M can be expressed as... 

The same critical potential is observed for intergranular fracture under fatigue conditions as for monotonic loading (SCC), provided that the loading frequency in fatigue is sufficiently low (/ < 0.1 Hz for R = 0.5, AK = 20 MPam / ) [28]. 

There are four main types of models for predicting failure under monotonic loading. The first type is stress-based failure models. A stress-based failure model, in its most general form, can be written/(ct ) > 0. Since stress is a tensor quantity, the failure model becomes a function of the six independent stress components. Thanks to the difficulty and the experimental effort needed to determine the six-dimensional failure envelope in stress space, the prob-... 

It is currently not well established which failure model is most appropriate for predicting failure of fluoropolymers that are monotonically loaded to failure. Commonly used approaches include the maximum principal stress, the maximum principal strain, the Mises stress, the Tresca stress, the Coulomb stress, the volumetric strain, the hydrostatic stress, and the chain stretch. In the chain stretch model, the failure is taken to occur when the molecular chain stretch, calculated fromPl... 

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