Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Primary stress

For purposes of this specification, stresses in the individual members of a latticed or trussed structure resulting from elastic deformation and rigidity of joints are defined as secondary stresses. These secondary stresses may be taken to be the difference between stresses from an analysis assuming fully rigid joints, with loads applied only at the joints, and stresses from a similar analysis with pinned joints. Stresses arising from eccentric joint connections, or from transverse loading of members between joints, or from applied moments, must be considered primary stresses. [Pg.512]

Allowable unit stresses may be increased 20% from the basic allowable stress when secondary stresses are computed and added to the primary stresses in individual members. However, primary stresses shall not exceed the basic allowable stresses. [Pg.512]

In the stress analysis of pressure vessels and pressure vessel components stresses are classified as primary or secondary. Primary stresses can be defined as those stresses that are necessary to satisfy the conditions of static equilibrium. The membrane stresses induced by the applied pressure and the bending stresses due to wind loads are examples of primary stresses. Primary stresses are not self-limiting if they exceed the yield point of the material, gross distortion, and in the extreme situation, failure of the vessel will occur. [Pg.809]

The primary stresses arising from these loads are considered in the following paragraphs, for cylindrical vessels Figure 13.17. [Pg.831]

Bradshaw (Bl) extended his MTES method to three-dimensional boundary layers, using the basic ideas to propose model equations for the vector sum and ratios of the two primary stresses, —uv and —wv. Johnston (J1) has compared the result of predictions by this method with his own data for an infinite swept flow. In particular, data show that the stress vector does not align with the strain-rate vector as the Newtonian closures assume. It was hoped Bradshaw s structural model would work better on this flow but Johnston s calculation shows that the angle of the shear stress vector is predicted quite poorly, although the mean velocity is predicted quite well. It is unlikely that MTE methods will ever predict this structural difference well, and one might hope that MRS methods will do considerably better. [Pg.225]

According to this equation, the thrust profile can, in principle, be measured on the upper cone or lower plate. Note that the normal stress differences are assumed to be independent of position. By plotting He0(r) against —ln r/R), a straight line is obtained from whose slope a combination of the primary ( (jxi) - CTee) and secondary (dee - normal stress differences is obtained. Though the pressure profile is difficult to measure, the primary stress difference can be readily determined from the force F exerted on the cone or plate. The value of F is given by... [Pg.545]

The strength of most materials is greater in compression than in tension. It is therefore unfortunate that technical difficulties prevent the direct application of tensile stresses. The compressive stresses commonly used in comminution equipment do not cause failure directly but generate by distortion sufficient tensile or shear stress to form a crack tip in a region away from the point of primary stress application. This is an inefficient but unavoidable mechanism. Impact and attrition are the other basic modes of stress application. The distinction between impact and compression is referred to later. Attrition, which is commonly employed, is difficult to classify but is probably primarily a shear mechanism. [Pg.3894]

Urea, the end product of nitrogen metabolism, accumulates rapidly in ARF. Most patients with ARF have a primary stressful illness that results in ureagenesis, and thus protein breakdown is markedly accelerated. Protein catabolism in ARF may be stimulated as the result of insulin resistance, metabolic acidosis, circulating proteases and inflammatory mediators, and the effects of uremic toxins. The mechanism may be direct, via modulation of protein synthesis, or indirect, by inhibiting the action of anabolic hormones. ... [Pg.2636]

This hypothetical problem serves to illustrate how categories and types of loadings are related to the stresses they produce. The stresses applied more or less continuously and uniformly across an entire section of die vessel are primary stresses. [Pg.6]

On the other hand, the stresses from the inward radial load could he either a primary local stress or secondary stress. It is a primary local stress if it is produced from an unrelenting load or a secondary stress if produced by a relenting load. Either stress may cause local deformation but will not in and of itself cause the vessel to fail. If it is a primary stress, the stress will be redistributed if it is a secondary stress, the load will relax once slight deformation occurs. [Pg.6]

Primary general stress. These stresses act over a full cross section of the vessel. They are produced by mechanical loads (load induced) and are the most hazardous of all types of stress. The basic characteristic of a primary stress is that it... [Pg.8]

A local primary stress is produced either by design pressure alone or by other mechanical loads. Local primary... [Pg.8]

Note For b and c it is necessary to subtract out the average stress which is the primary stress. Only the vary ing part of the stress distribution is a secondary stress. [Pg.9]

Lexical stress is manifested at the syllable level. Exactly one syllable in a word is designated as the primary stressed syllable, all other syllables have either secondary stress or are reduced. [Pg.192]

For languages such as English, three levels of stress are necessary. While some phonological systems use more (e.g. SPE), our experience has shown that, at the lexical level at least, three is clearly sufficient. Following from a convention adopted for TIMIT, we use 1 for primary stressed syllables, 2 for secondary stressed syllables and 0 for reduced syllables. The stress niunbers are placed adjacent and after the vowel, so, for example, the entry for information would be /ih2 n. f axO. m eyl. sh axO n/. [Pg.207]

If lexical stress is a relative phenomenon, what of single-syllable words Since there are no other syllables to contrast with, the stress status of such words is technically undefinable. However, by convention, most of these words are given a primary stress or strong stress in their syllable. The exception is content words, which are given a primary stress if in their full form (/f r ah m/) or no stress in their reduced form (/f r ax m/). [Pg.188]


See other pages where Primary stress is mentioned: [Pg.311]    [Pg.553]    [Pg.831]    [Pg.9]    [Pg.28]    [Pg.38]    [Pg.903]    [Pg.398]    [Pg.828]    [Pg.188]    [Pg.213]    [Pg.1000]    [Pg.67]    [Pg.75]    [Pg.457]    [Pg.868]    [Pg.56]    [Pg.6]    [Pg.7]    [Pg.8]    [Pg.8]    [Pg.8]    [Pg.1102]    [Pg.245]    [Pg.128]    [Pg.188]    [Pg.190]    [Pg.208]    [Pg.187]   


SEARCH



© 2024 chempedia.info