Tensile strength ultimate

Landel and Fedors (1965) pointed out that the ultimate tensile strength cr of an elastomer may be written under certain conditions as follows  

One aspect that may tend to clarify the near constancy of n involves the fact that for normally crosslinked elastomers, values of n are largely controlled 

---

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. 

Fatigue. Engineering components often experience repeated cycles of load or deflection during their service fives. Under repetitive loading most metallic materials fracture at stresses well below their ultimate tensile strengths, by a process known as fatigue. The actual lifetime of the part depends on service conditions, eg, magnitude of stress or strain, temperature, environment, surface condition of the part, as well as on the microstmcture. 

Fig. 11. Test temperature vs ultimate tensile strength for pure refractory metals (52) (---) rhenium (—...

Table 13 is a representative Hst of nickel and cobalt-base eutectics for which mechanical properties data are available. In most eutectics the matrix phase is ductile and the reinforcement is britde or semibritde, but this is not invariably so. The strongest of the aHoys Hsted in Table 13 exhibit ultimate tensile strengths of 1300—1550 MPa. Appreciable ductiHty can be attained in many fibrous eutectics even when the fibers themselves are quite britde. However, some lamellar eutectics, notably y/y —5, reveal Htde plastic deformation prior to fracture. 

Material Percent neutralized Melt index at 190°C, dg/min Secant modulus, % extension, MPa Ultimate tensile strength, MPa Elongation at break, %... 

Cold-roUed alloys of lead with 0.06 wt % teUurium often attain ultimate tensile strengths of 25—30 MPa (3625—5350 psi). High mechanical strength, excellent creep resistance, and low levels of alloying elements have made lead—teUurium aUoys the primary material for nuclear shielding for smaU reactors such as those aboard submarines. The aUoy is self-supporting and does not generate secondary radiation. 

Ra.m Tensile. A ram tensile test has been developed to evaluate the bond-2one tensile strength of explosion-bonded composites. The specimen is designed to subject the bonded interface to a pure tensile load. The cross-section area of the specimen is the area of the aimulus between the outer and inner diameters of the specimen. The specimen typically has a very short tensile gauge length and is constmcted so as to cause failure at the bonded interface. The ultimate tensile strength and relative ductihty of the explosion-bonded interface can be obtained by this technique. 

Both % El and % RA are frequendy used as a measure of workabifity. Workabifity information also is obtained from parameters such as strain hardening, yield strength, ultimate tensile strength, area under the stress—strain diagram, and strain-rate sensitivity. 

Treatment Yield strength, MPa Ultimate tensile strength, MPa Elongation, %... 

AHoy base Rare-earth addition, % AST M Grade Condition Density, g/cc Ultimate tensile strength, MPa Typical mechanical properties, RT Yield Elongation, % strength, MPa Elastic modulus, GPa... 

The alloy name in the United States can include a company name or trademark in conjunction with the composition for alloyed titanium or the strength, ie, ultimate tensile strength for Timet and yield strength for other U.S. producers, for unalloyed titanium. The common alloys and specifications are shown in Table 14. 

There is still a substantial safety margin up to the ultimate tensile strength, which amounts to 60 to 90 percent, depending on the steel (Kirby, Siwek, Treventing Failures of Equipment Subject to Explosions, Chemical Engineering, Jtine 23, 1986). 

Ultimate tensile strength the maximum stress value as obtained on a stress-strain curve (Figure 30.1). 

Production platforms are coated only in exceptional cases or for the purposes of investigation because the life of the structure is greater than the life of the coating. Therefore in the design of the cathodic protection, only the protection potential Us of the steel need be considered. Steels with an ultimate tensile strength of up to 350 N mm are used for these structures, which are weldable even in thick sections, and the hardness of the welded material can be kept to 350 HV (see Section 2.3.4 [2,10]). Aluminum anodes with the same protection effect and life as zinc anodes have much less weight. This is a very important advantage for... 

Table 4.1 Factors of safety for ductile and brittle materials and various loading conditions (values shown in brackets from 1905, without brackets from 1965) (,S = ultimate tensile strength,, Sy = yield strength)...

Normal - Toleranees, ultimate tensile strength, uniaxial yield strength and shear yield strength of some metallie alloys... 

It has been argued that material properties sueh as the ultimate tensile strength have only positive values and so the Normal distribution eannot be the true distribution. 

The largest design dependent strength variable is material strength, either ultimate tensile strength (Su), uniaxial yield strength (Sy), shear yield strength (Ty) or some... 

It has been shown that the ultimate tensile strength, Su, for brittle materials depends upon the size of the speeimen and will deerease with inereasing dimensions, sinee the probability of having weak spots is inereased. This is termed the size effeet. This size effeet was investigated by Weibull (1951) who suggested a statistieal fune-tion, the Weibull distribution, deseribing the number and distribution of these flaws. The relationship below models the size effeet for deterministie values of Su (Timoshenko, 1966). 

Sui = ultimate tensile strength of test speeimen Su2 = ultimate tensile strength of eomponent vi = effeetive volume of test speeimen V2 = effeetive volume of eomponent design... 

Many meehanieal eomponents also operate at temperatures far lower than room temperature. As the temperature is redueed, both the ultimate tensile strength, Su, and tensile yield strength, Sy, generally inerease for most materials. Flowever, temperatures below freezing have the effeet of altering the strueture of some duetile... 

Sy = yield strength Su = ultimate tensile strength L = loading stress Ty = shear yield strength. 

By definition, a brittle material does not fail in shear failure oeeurs when the largest prineipal stress reaehes the ultimate tensile strength, Su. Where the ultimate eompressive strength, Su, and Su of brittle material are approximately the same, the Maximum Normal Stress Theory applies (Edwards and MeKee, 1991 Norton, 1996). The probabilistie failure eriterion is essentially the same as equation 4.55. 

The effeetive stress is then eompared to the materials ultimate tensile strength, Su the reliability is given by the probabilistie requirement to avoid tensile fraeture (Norton, 1996) ... 

Experimental determination of ultimate tensile strength of the weak link material... 

---