Cracking severity, measures

CSI, defined as the Cracking Severity Index, is a direct measure of cracking severity (25). 

Previous work pursued the model analytically, for a linearly elastic [5] (or, later, non-linearly elastic [6]) material with constant thermal properties. The analytical model explained several measured fracture properties of thermoplastics the magnitude of impact fracture toughness and its dependence on impact speed [7] and the absolute magnitude of resistance to rapid crack propagation [8]. Recent results have shown that the impact fracture properties of some amorphous and crosslinked polymers show the same rate dependence [11],... 

This method involves critical load evaluation and crack depth measurement, and has been used in recent years to define fracture parameters in several ceramics, for example, UO2, SiC, and TiC. ° ... 

Moorman, J.W., "Space velocity and catalyst-to-oil ratio together provide a measure of cracking severity". Oil and Gas J., 52(44), 108 (1954). 

One of the main risks for a submerged concrete structure is its rupture due to cracking. Several techniques are devoted to measure and monitor the evolution of cracks in concrete. In the case of a reinforced concrete structure, the steel frame has indeed strengthened the material property, but can also be a cause of new cracks because of its own corrosion. 

The Stability of crack growth in this work allowed several measurements to be made on each specimen. A crosshead speed of 0.2 mm/min was used giving an average crack front velocity of 1 mm/min. 

In this paper we present simulations and measurements of several types of excitation coils, which match the special requirements for a SQUID based eddy current NDE system. We note however that all calculations presented here on penetration depths, current distributions and crack-detecting algorithms are also useful for conventional eddy current testing systems. 

Chapter 4.3. discusses the explained theory for choosed examples. For several cracks the output is pre-calculated by using the impulse response and compared with measurement data. 

Conversion. The terms severity or conversion are used to measure the extent of cracking. Conversion can easily be measured for a single component (C) feed and is defined as follows, where the quantities are measured ia weight units. 

The slow rate of hydration for buried surfaces is desirable from a service point of view, but makes the study and evaluation of the durability of surface treatments difficult unless wedge tests (ASTM D3762) or similar tests are used to accelerate the degradation. As for the wedge test, the stress at the crack tip, together with the presence of moisture at the tip, make this a more severe test than soaked lap shear specimens or similar types and therefore a better measure of relative durability. 

Any test (several such tests are used) in which time to failure of smooth specimens is determined is an overall measure of the incubation period to initiate a crack, the ability to resist the propagation of a stress corrosion crack and the ability to resist final mechanical fracture. Since this test does not indicate the relative merits of an alloy in each individual aspect of the... 

Fracture Mechanics Tests One problem of both sustained load and slow strain-rate tests is that they do not provide a means of predicting the behaviour of components containing defects (other than the inherent defect associated with the notch in a sustained load test). Fracture mechanics provides a basis for such tests (Section 8.9), and measurements of crack velocity as a function of stress intensity factor, K, are widely used. A typical graph of crack velocity as a function of K is shown in Fig. 8.48. Several regions may be seen on this curve. At low stress intensity factors no crack growth is... 

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