Strain rupture

Rupture. Rupture strain decreases steadily with increases in the duration of stress. Alternately, the magnitude of stress needed to cause rupture decreases as the duration of stress increases. Figure 2-31 shows the development first of damage and then of yielding in a PVC compound as a function of its being under sustained stress. The decay at the onset of the first damage and of yield... 

Structural dements resist blast loads by developing an internal resistance based on material stress and section properties. To design or analyze the response of an element it is necessary to determine the relationship between resistance and deflection. In flexural response, stress rises in direct proportion to strain in the member. Because resistance is also a function of material stress, it also rises in proportion to strain. After the stress in the outer fibers reaches the yield limit, (lie relationship between stress and strain, and thus resistance, becomes nonlinear. As the outer fibers of the member continue to yield, stress in the interior of the section also begins to yield and a plastic hinge is formed at the locations of maximum moment in the member. If premature buckling is prevented, deformation continues as llic member absorbs load until rupture strains arc achieved. 

Fig. 4.1 Tensile creep curves for siliconized silicon carbide (Carborundum KX01). Over most of the data range, these data can be represented by a constant creep rate there is a short primary creep stage, and almost no tertiary creep. The rupture strain decreases with increasing creep rate. The strain to failure, =1.5%, indicates brittle behavior even at low rates of creep detormation. Figure from Ref. 28.

Otero et al. (1998) demonstrated that high-pressure frozen eggplant samples had higher firmness and lower rupture strain and drip loss compared to those of still-air-frozen samples. The improved quality was attributed to the formation of heavy ice polymorphs due to freezing of water under high pressure (100-700 MPa), leading to volume reduction. 

Tables 2-4 show the effect of the dry/cold. moderate, and humid/hot environments on the tensile properties of the adhesive FM 300K tested at the 10 "/s. lO /s. and lO Vs strain rates, respectively. The values of the yield strength, the yield strain, and the offset obtained with the SED method and the corresponding values from the 0.2 % offset method are shown. The tensile strength, rupture strain, and elastic modulus are provided for information. On average, the time to rupture of the specimens tested at the lO /s, lO /s, and lO Vs strain rates were 4 seconds. 6 minutes, and 15 hours, respectively. The data are listed in ascending order of yield strength. The tensile properties listed in parentheses at the bottom of each cell are averages for replicate specimens. For ease of comparison, these averages are summarized in Table 5.

Specimen ID. Yield Strength (MPa) Yield Strain Offset (%) Yield Strength (MPa) Yield Strain Tensile Strength (MPa) Rupture Strain Elastic Modulus (MPa)... 

Yield Yield Tensile Rupture Strain Elastic... 

FIG. 7. Specific rupture strain power as a function of tube temperature A, first polynomial in Table 6, T < 780°C B, second polynomial, T > 780°C. 

Jacques D, Favre JP, Determina tion of the interfacial shear strength by fibre fragmentation in resin systems with a small rupture strain, 6th International Conf on Composite Mater, Matthews FL, Buskell NCR, Hodgkinson JM eds., Elsevier Applied Science, New York, 5, 471, 1987. 

If lipid membranes are subjected to lateral tension, they typically rupture at stresses of several millinewtons per meter (mN/m), with a remarkably low rupture strain of only a few percent [3]. At large scales and moderate tensions it is hence an excellent approximation to consider membranes as largely unstretchable two-dimensional surfaces. Their dominant soft modes are not associated with stretching but with bending [4-6]. Within the well-established mathematical framework developed by Helfrich [5], the energy of a membrane patch 5, amended by a contribution due to its boundary dt [7], is expressible as ... 

The rupture strains of FRP measured in recent tests on FRP-confined concrete cylinders are substantially below those from flat coupon tensile tests [71-73]. This discrepancy is attributed mainly to the curvature of the FRP jacket and the non-uniform deformation of concrete. 

Tension testing of a vulcanized elastomer also permits the determination of the tensile strength, which is the maximiun stress applied during stretching a specimen to rupture the corresponding rupture strain is called the maximum extensibility (49-52). Typical values are given in Table 1 (14). Dumbbell and ring specimens can be used. 

Rupture. Rupture strain decreases steadily with increases in the duration of stress, as discussed. Alternately, the magnitude of stress needed to cause rupture decreases as the duration of stress increases. 

When ceria is used as a membrane, significant stoichiometry variations may be induced over the membrane. As the unit cell volume of ceria depends on the oxygen content (cf. Section 12.2.2.3) this results in a strain profile across the membrane, which leads to mechanical stresses. The strain associated with stoichiometry changes may, as discussed in Section 12.2.2.3, be of the order of 1-2%. Typical rupture strain levels in ceramics are of the order of 0.1%. This means that these lattice strains can result in mechanical... 

The time dependence of the breaking stress and strain measured at different temperatures often follows the time-temperature superposition principle (9> 12), to give a single conrposite curve. Typically, the rupture stress superposes more smoothly than the rupture strain. When the reduction is carried out for Galcit the breaking... 

When the looped fibre is loaded, its curvature is increased and the rupture strain in the outer zone at the moment of the break of fibre is... 

The nominal tensile strength //Aq is the maximum tensile stress which a material is capable of sustaining. The maximum extensibility is the corresponding rupture strain A,. These ultimate tensile properties of elastomeric networks are very sensitive to temperature and test conditions, but can be characterized by a failure envelope which is generally represented by a plot of log(/ro/AoT) vs. log(A, — 1) where Tand To are respectively the test temperature and a reference temperature. ... 

An alternative approach is to treat the problem statistically. There is always uncertainty in the conditions of an irradiation, in the materials data, and in the creep rupture relations for the clad. Garkisch has estimated the statistical variation in creep rupture strain, thermal and... 

FIG. 3 The three stages of creep are schematically shown as they occur over time. The symbols and n are the corresponding rupture strains and time, respectively. Subscripts 1 and 2 represent the ends of stages I and II, respectively. 

---