Stress normalised

Figure 9.12 Normalised stress versus cycles for failure with compression stress normalised against compression after impact strength 25% and 50% refer to damage as a % of sample width.

Figure 5.13 Stress distribution around bolt holes for basic load case 1. Stress normalised by nominal bearing stress S b = F/dt. ...

Normalised fiber mechanical properties are expressed in terms of unit linear density. For example, in describing the action of a load on a fiber in a tensile test, units of N/tex or gram force per denier (gpd) are generally used. If this is done, the term tenacity should be used in place of stress. The tme units of stress are force per unit cross-sectional area, and the term stress should be reserved for those instances where the proper units are used. 

A more extensive comparison of many potential turbine blade materials is available (67). The refractory metals and a ceramic, sHicon nitride, provide a much higher value of 100 h stress—mpture life, normalised by density, than any of the cobalt- or nickel-base aHoys. Several intermetaHics and intermetaUic matrix composites, eg, aHoyed Nb Al and MoSi —SiC composites, also show very high creep resistance at 1100°C (68). Nevertheless, the superaHoys are expected to continue to dominate high temperature aHoy technology for some time. 

For normal commercial-quality mild steels in the annealed or normalised conditions in which they are almost invariably used, various workers have shown that the carbon content of the steel is the major factor determining intergranular cracking susceptibility. Figure 8.13 shows the threshold stresses for a series of commercial mild steels of different carbon contents caused to crack in boiling 4n NH4NO3. The trend of the result suggests... 

Fig. 8.95 Time to failure ratios from constant-deflection rate tests and normalised threshold stresses

It must always be remembered that diffusion coatings are produced by a form of heat treatment and that, with the exception of low-temperature zinc diffusion (sherardising), the treated ferrous materials are usually in the annealed condition. Whenever the mechanical properties of the parts must be restored to their original level, a subsequent heat treatment is necessary . This does not as a rule present any difficulty with chromised or boronised steels. In order to prevent undue distortion and internal stresses during treatment and subsequent hardening, it is recommended that high-carbon and alloy steels should be processed in the normalised condition. 

Figure 6.22 Comparison of Graessley and Doi-Edwards models for normalised stress versus normalised shear rate. Also shown is an estimate of the role of short time Rouse relaxation mechanisms within the tube...

The experiment here is a small rapid shear-strain at time zero - after this the shear stress in a viscoelastic liquid will not vanish instantaneously, but decay as a characteristic function with time. When normalised by the strain to yield the dimensions of modulus, this is G(f). 

NOTE Good design practice should be followed in the selection of fabrication methods, welding procedures, and materials for vendor-furnished steel pressureretalning parts that may be subject to temperatures below the ductile-brittle transition temperature. The published design-allowable stresses for metallic materials in internationally recognised standards such as the ASME Code and ANSI standards are based on minimum tensile properties. Some standards do not differentiate between rimmed, semi-killed, fully killed hot-rolled and normalised material, nor do they take into account whether materials were produced under fine- or course-grain practices. The vendor should exercise caution in the selection of materials intended for services between 0 °C (-20 °F) and 40 °C (100 °F). 

In order to check whether the temperature dependence of oy would reflect the change of modulus only, the ratio cry/E is plotted in Fig. 19. It is clear that the modulus does not normalise the yield stress behaviour, the latter decreasing more than the modulus when temperature increases. 

The results for SSA normalised by the plastic flow stress, nSSA, (defined in Sect. 2.2.3) are shown in Fig. 92. It is striking to see how different are the temperature dependencies of SSA and nSSA. A similar difference is encountered in the case of BPA-PC (Sect. 4.1.1.3). Nevertheless, the observation that the lactam-12 content (x = 1 or 1.8) leads to two different behaviours remains (Fig. 91 for II and 1.81), as well as the fact that in each family, similar shapes are obtained independently of the iso- or tere-nature of the phthalic unit. 

In these maps the strength (common, ) is plotted versus the temperature (common, °C, and normalised, T/Tg) the diagram obtained is thus subdivided into fields in which a single mechanism will allow failure at a lower stress than any other these fields represent a regime ... 

Two common properties which can be calculated from the minimum-energy structure are the elastic and dielectric constants. The elastic constant matrix is used to relate the strains of a material to the internal forces, or stresses It is defined as the second derivative of the energy with respect to the strain, normalised by the cell volume. The inverse of the elastic... 

Specific volume at yielding was observed from initial moisture contents and volume change during shearing. Identified yield stresses were normalised with respect to the equivalent pressure, which were calculated using specific volume at yielding (Equation 1). Normalised yield envelopes. 

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