Tensile strength

Phase strength, kg/mm2 pera- ture, c Ref. Year Remarks 

CraC2 wc 1.7 1000 [140] 1961 / strength after 100 hr (data taken from graph) 

Stress-rupture strength after 10 hr (data taken from graph) 

Dobrovorskii, Specimens prepared by cold-pressing followed by sintering, [1035] 

Tensile strength is a fundamental failure property and it represents the minimum force required to cause separation of a bulk structure without the complications of overlapping boundaries and other disturbances in the failure plane. 

The tensile strength (tensile stress) is a measure of the basic strength of a material. It is the maximum stress that the material will withstand, measured by a standard tensile test. The older name for this property, which is more descriptive of the property, was Ultimate Tensile Strength (UTS). 

The design stress for a material, the value used in any design calculations, is based on the tensile strength, or on the yield or proof stress (see Chapter 13). 

Proof stress is the stress to cause a specified permanent extension, usually 0.1 per cent. 

ASTM D897-01 Standard test method for tensile properties of adhesive bonds. 

ASTM D1144-99 Standard practice for determining strength development of adhesive bonds. 

ASTM D1344-03 Standard method of testing cross-lap specimens for tensile properties of adhesives. 

ASTM D2095-96 (2002) Standard test method for tensile strength of adhesives by means of bar and rod specimens. 

Both polychloroprenes, M and N, and hydrogenated nitrile rubber N2 showed an upturn in strength at the highest temperature only, indicating the onset of a different mechanism. The nitrile P showed this at 90 °C and 100 °C but it was followed by a downturn in strength at 100 °C. The nitrile R had a somewhat curious scatter of results at 70 °C. 

There was indication of cyclic behaviour for the hydrogenated nitrile rubber N2, chlorinated polyethylene N4, nitrile rubber P4 and Vamac material P6. Compounds N2 and P6 appeared to have maxima, followed by a minimum in the case of compound P6. Compounds N4 and P4 possibly had minima. The tensile strength of compound N5 apparently changes direction falling slightly in strength at 150 °C then rising at 210 °C. 

These observations show that the development of high tensile strength in rubberlike polymers ordinarily is intimately related to crystallization. As a matter of fact, this generalization applies in large measure to nonrubberlike. polymers where crystallization is known to enhance markedly the strength (especially the impact 

As the proposed modeling scheme is based on the kinetic processes of the resin, tensile strength at lower temperatures, where fiber failure occurred, cannot be 

Mechanical properties of polymers are dependent on their molecular weight, orientation and crystallinity, material purity, the presence of defects, voids, and/or reinforcing elements in the material, and, polymer chemical structure. Polymer tensile strength and moduli increase with increasing molecular weight up to a plateau of molecular weight, which differs for different polymers [90]. 

The determination of the mechanical properties of a buccal film is usually based on the ASTM D882 method [39]. 

The modest change in the Yoimg s modulus between the pure material and the allo) is quite evident. In the case of the steels, the lowest carbon steel (since iron must contain a minimal amount of carbon to be considered a steel) is used as a basis. The enormous 

Source From Callister, W.D. Materials Science and Engineering An Introduction, 7th edn., John Wiley Sons, New York, 2007. 

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Strong acids completely hydrolyse cellulose to glucose very mild hydrolysis gives hydrocelluloses with shorter chains and lower viscosity and tensile strength. Under special conditions a large yield of cellobiose is obtained. 

The importance of polymer composites arises largely from the fact that such low density materials can have unusually high elastic modulus and tensile strength. Polymers have extensive applications in various fields of industry and agriculture. They are used as constructional materials or protective coatings. Exploitation of polymers is of special importance for products that may be exposed to the radiation or temperature, since the use of polymers make it possible to decrease the consumption of expensive (and, sometimes, deficient) metals and alloys, and to extent the lifetime of the whole product. 

Fig. 10 shows the relation between the tensile strength [Pg.837]

Relation between tensile strength a B of joint and defect area s ratio Sr/So... 

The tensile strength in the joint part shown Fig.ll has less than the maetrial strength. As for this, joint strength is thought to be a decrease more than the strength of Ti because of an increase in the intermetallic compound of TiC that a little brittle. 

Most solid surfaces are marred by small cracks, and it appears clear that it is often because of the presence of such surface imperfections that observed tensile strengths fall below the theoretical ones. For sodium chloride, the theoretical tensile strength is about 200 kg/mm [136], while that calculated from the work of cohesion would be 40 kg/mm [137], and actual breaking stresses are a hundreth or a thousandth of this, depending on the surface condition and crystal size. Coating the salt crystals with a saturated solution, causing surface deposition of small crystals to occur, resulted in a much lower tensile strength but not if the solution contained some urea. 

Secondly, the ultimate properties of polymers are of continuous interest. Ultimate properties are the properties of ideal, defect free, structures. So far, for polymer crystals the ultimate elastic modulus and the ultimate tensile strength have not been calculated at an appropriate level. In particular, convergence as a function of basis set size has not been demonstrated, and most calculations have been applied to a single isolated chain rather than a three-dimensional polymer crystal. Using the Car-Parrinello method, we have been able to achieve basis set convergence for the elastic modulus of a three-dimensional infinite polyethylene crystal. These results will also be fliscussed. 

Polymerisation of a diol with a dicarboxybe acid is exemplified by the production of a polyester from ethylene glycol and terephthabc acid either by direct esterification or by a catalysed ester-interchange reaction. The resulting polyester (Terylene) is used for the manufacture of fibres and fabrics, and has high tensile strength and resibency its structure is probably ... 

An area of great interest in the polymer chemistry field is structure-activity relationships. In the simplest form, these can be qualitative descriptions, such as the observation that branched polymers are more biodegradable than straight-chain polymers. Computational simulations are more often directed toward the quantitative prediction of properties, such as the tensile strength of the bulk material. 

Commercially produced elastic materials have a number of additives. Fillers, such as carbon black, increase tensile strength and elasticity by forming weak cross links between chains. This also makes a material stilfer and increases toughness. Plasticizers may be added to soften the material. Determining the effect of additives is generally done experimentally, although mesoscale methods have the potential to simulate this. 

Copolymerization can be carried out with styrene, acetonitrile, vinyl chloride, methyl acrylate, vinylpyridines, 2-vinylfurans, and so forth. The addition of 2-substituted thiazoles to different dienes or mixtures of dienes with other vinyl compounds often increases the rate of polymeriza tion and improves the tensile strength and the rate of cure of the final polymers. This allows vulcanization at lower temperature, or with reduced amounts of accelerators and vulcanizing agents. 

This thermoplastic shows good tensile strength, toughness, low water absorption, and good frictional properties, plus good chemical resistance and electrical properties. 

Rubber Specific gravity Durometer hardness (or Shore) Ultimate elongation % (23°C) Tensile strength, lb in 2 (23°C) Service temperature, °C ... 

Thus the hysteresis loop should close at a relative pressure determined by the tensile strength of the liquid adsorptive, no matter whether the pore system extends to finer pores than those characterized by or not. 

The most direct test of the tensile strength hypothesis would be to compare the value of Tq calculated from the closure point of the isotherm by Equation (3.61) with the tensile strength of the bulk liquid determined directly. Unfortunately, experimental measurement of the tensile strength is extremely difficult because of the part played by adventitious factors such as the presence of solid particles and dissolved gases, so that the values in the literature vary widely (between 9 and 270 bar for water at 298 K, for example). 

It is, however, possible to calculate the tensile strength of a liquid by extrapolation of an equation of state for the fluid into the metastable region of negative pressure. Burgess and Everett in their comprehensive test of the tensile strength hypothesis, plot the theoretical curves of T /T against zjp, calculated from the equations of state of van der Waals, Guggenheim, and Berthelot (Fig. 3.24) (7], and are the critical temperature and critical... 

Fig. 3.24 Test of the tensile strength hysteresis of hysteresis (Everett and Burgess ). TjT, is plotted against — Tq/Po where is the critical temperature and p.. the critical pressure, of the bulk adsorptive Tq is the tensile strength calculated from the lower closure point of the hysteresis loop. C), benzene O. xenon , 2-2 dimethyl benzene . nitrogen , 2,2,4-trimethylpentane , carbon dioxide 4 n-hexane. The lowest line was calculated from the van der Waals equation, the middle line from the van der Waals equation as modified by Guggenheim, and the upper line from the Berthelot equation. (Courtesy Everett.)...

A different approach is followed by Kadlec and Dubinin who calculate the theoretical tensile strength from a 6-12 relation for molecular forces (cf. Section 1.3) as... 

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