Notched tensile strength

In the majority of cases, the tests are conducted using a dead-weight lever-arm stress-rupture rig with an electric timer to determine the moment of fracture, but a variety of test rigs similar to those shown in Fig. 8.89g are also used. The evaluation of embrittlement may be based on a delayed-failure diagram in which the applied nominal stress versus time to failure is plotted (Fig. 8.103) or the specimen may be stressed to a predetermined value (say 75% of the ultimate notched tensile strength) and is considered not to be embrittled if it shows no evidence of cracking within a predetermined time (say 500 h). Troiano considers that the nature of delayed fracture failure can be described by four parameters (see Fig. 8.103) ... 

Tests may include tensile elongation, sharp-notch tensile strength (to be compared with unnotched tensile strength), and/or other tests, conducted at or below design minimum temperature. See also para. GR-2.1.3(d). 

Percent Rubber Izod Impact Strength, ft-lb/inch of Notch Tensile Strength, psi... 

Izod impact strength (notched) Tensile strength Tensile modulus Elongation at break Flexural modulus Flexural strength... 

Impact strength (Izod cm N/cm of notch) Tensile strength (kPa)... 

Notch tensile strength of steel containing hydrogen... 

Alloy and temper Tensile Yield Elongation Temperature, strength, strength, in 2 in, °F psi psi % Notch tensile strength, psi Notch strength ratio Notch yield ratio... 

The results of the tests of the smooth and sharply notched Kt >17) specimens are shown in Table II. The notch strength ratios (ratio of notch tensile strength to tensile strength) and notch yield ratios (ratio of notch tensile strength to tensile yield strength) are shown in Fig. 2 as a function of temperature. 

Alloy and temper Thickness Temperature Tensile strength Tensile yield strength, (TYS)t Elongation in 4D, % Notch- tensile strength (NTS) NYR, NTS TYS Tear strength (ST), Ratio, ST TYS Unit propagation energy ... 

An indication of the inherent ability of a material to plastically deform locally in the presence of a severe stress-raiser is provided by the notch-yield ratio (NYR)—the ratio of the notch-tensile strength to the tensile yield strength. 

The effect of surface treatment on the mechanical properties of carbon-fibre composites Brittle fibres in a brittle matrix can have appreciable toughness because the cracks can get diverted along the fibre-matrix interface. If the bond is weak the composite will not support loads in shear or compression, but when the bond is too strong, the material will be brittle. These aspects are illustrated in Fig. 6, where it is seen that the interlaminar shear strength reaches a plateau but the notched tensile strength decreases... 

Fig. 6. Effect of surface treatment (degree of fibre treatment, DFT) on the mechanical performance of Type n carbon fibre epoxy composites. (1) Interlaminar shear strength of a unidirectional composite, (2) impact strength (3) notched tensile strength, of a...

Of the four alloys tested AISI 304 exhibited the best combination of strength and toughness. However, the notch-tensile strength was found to decrease between 76 and 20°K. 

In analyzing localized heating at low temperatures one must consider the sharp decrease in specific heat at low temperatures and the approach toward adi atic conditions provided by an increase in strain rate. The ultimate tensile stress decline with strain rate found in testing AISI 304 at 20 K may be associated with this localized heating effect since a temperature rise would result in a lower fracture stress (Fig. 5). An increase in ultimate notch-tensile strength with an increase in strain rate would also be consistent with a temperature-dependent fracture stress (Fig. 5) since the ultimate notch-tensile strength increases with increasing temperature between 20 and 76 K. 

Fig. 3. Notched tensile strengths (ksl) and notched/iinnotched tensile ratios for 7000 series aluminum alloy sheet vs. temperature.

The notched tensile strengths which indicate notch sensitivity and the notched/unnotched tensile ratios which may be used as indices for resistance... 

ItemDerature Ultimate tensile strength ItensUe yield strength Elongation, % Reduction of area. Notch tensile strength(a) Young s modulus ... 

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