Tensile creep rupture data

Lyons [142] obtained creep rupture data and tensile behaviour of glass filled PA and polyphthalamides at temperatures between 23-150 °C. A polyphthalamide with... 

Fig. 36. Comparison of cr—N curve under a square-wave loading with creep-rupture data for a typical ABS polymer (175). Note that the creep-rupture time scale is equivalent to that of the fatigue cycle scale in terms of time under tensile load. To convert MPa to psi, multiply by 145.

Li Huang et al. [16] discussed the mechanical properties of polyamides. Lyons [17] obtained creep rupture data and tensile behavior for glass-filled polyamide and polyphthalamide at 2.3°C-150°C. 

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.

What this relationship, in effect, says is that every material will fail during creep when the strain in that material reaches a certain value independent of how slow or how fast that strain was reached. That the Monkman-Grant expression is valid for Si3N4 is shown in Fig. 12.14, where the range of data obtained for the vast majority of tensile stress rupture tests lies in the hatched area. On such a curve, Eq. (12.42) would appear as a straight line with a slope of 1, which appears to be the case. 

The tensile creep and creep rupture properties of Prepreg HiPerComp composites have also been evaluated in air for times up to 1000 hours. These data are summarized in... 

Equation (13.6) was used to develop a set of creep rupture envelopes to predict attainable creep rupture time at given load L for three mega-coupled composites at 80°C as shown in Fig. 13.18. With measured data only at creep rupture times <100 hr for accelerated tensile creep determinations, we can make estimates for anticipated service lifetime as a function of applied stress load that is indicated by the weight L. 

Figure 5. Tensile creep total strain and electrical resistance curves for isothermal (ZMI-3) and thermal gradient (ZMI-1) conditions. Note that the data for the specimen that did not rupture is indicated by arrows.

Example 4.1. A user is requesting code approval for a new material that has a minimum specified tensile stress of 120 ksi and a minimum specified yield stress of 60 ksi at room temperature. Tensile and yield values for various heats and temperatures are shown in Fig. 4.5. Creep and rupture data are given in Figs. 4.6 and 4.7, respectively. What are the allowable stress values at 300 and 1200°F based on criteria given in Section 2.4 ... 

Table 3.1-25 Selected tensile data for yield stress R, fracture stress R. total elongation A, fracture toughness K c at room temperature, and creep time to rupture at 650 °C and 380 MPa for various Tis Al-based alloys...

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