Impact curves

Fig. 1.11. The normalized angular momentum correlation function Kj(t)/Kj(0) at k — 0.25 in differential (curve a), integral (curve b) and impact (curve c) theories.

Hadean and this can be scaled up, largely in terms of relative cross-sectional area, to yield an impact curve for the Earth (Sleep et ai, 1989). 

Fig. 7.7, which shows an analogous experiment using HPP. In both cases, flexural modulus decreases roughly linearly with modifier addition, whereas the increase in Izod impact follows an S curve. Using ICP, the impact curve rises at a lower modifier level (about 10% compared with 15% with HPP) and plateaus at a lower level (about 20% versus about 40% for HPP). 

Figure 1.73 illustrates the instrumented CIT system in a block diagram and the impact-response curve method, as applied to the above tests. In addition to the aforementioned partially stabilized zirconia (PSZ ZrOi-S mol%Y203), samples of S3N4 were also investigated by Kobayashi et al. [32], Typical hammer load-times and strain-gage signal-time curves of PSZ and Si3N4 are found in Fig. 1.74. The impact-response curves of PSZ and S3N4, at several impact velocities are shown in Fig. 1.75. The impact curves of these specimens are impact-velocity-dependent. This technique enables the determination of the dynamic fracture toughness of these ceramics by means of the impact-response curve method. Impact-response curves quantitatively relate the response of the specimen to the impact, which depends solely on the elastic reaction between the specimen and the actual impact.

The prediction of impact curves from experiments at low strain rates. 

As a typical example, fig. 8 illustrates the effect of rare earth addition on toughness the impact curves are plotted for both longitudinal and transverse Charpy V-notch specimens (Luyckx et al. 1970). In longitudinal specimens, the impact energy at 100% shear, commonly called the shelf energy, is in excess of 5.5 kg m (40 ft lb) in transverse specimens, it is 2kgm (15 ft lb), which is doubled to 4kgm at the Ce/S ratio of 1.5-2.0. 

As a portion of the brittle fracture study a plate of A-70 titanium containing 400 ppm of hydrogen was tested. The results from this plate gave impact curves that were not affected by orientation and had a sharp break similar to steels. The NDT temperature for this brittle plate was 100°C and was located at the lower break of the impact curve. With this... 

The stated objective of appraisal activity is to reduce uncertainty. The impact of appraisal on uncertainty can be shown on an expectation curve, if an outcome is assumed from the appraisal. The following illustrates this process. 

Figure 7.3 Impact of appraisal well A on expectation curve...

The point t, on the abscissa denotes the end of the active stage of the impact, or time of the indenter intrusion The break of the contact of indenter with material tested is designated by Xk Analyzing the curves V(t), a(t) and F(t), it is seen that the maximum of the contact force does not coincide in time with the moment of achievement of the maximum intrusion and zero... 

Mechanical properties of plastics can be determined by short, single-point quaUty control tests and longer, generally multipoint or multiple condition procedures that relate to fundamental polymer properties. Single-point tests iaclude tensile, compressive, flexural, shear, and impact properties of plastics creep, heat aging, creep mpture, and environmental stress-crackiag tests usually result ia multipoint curves or tables for comparison of the original response to post-exposure response. 

The superheated steam generated in the superheater section is coHected in a header pipe that leads to the plant s high pressure steam turbine. The steam turbine s rotor consists of consecutive sets of large, curved, steel aHoy disks, each of which anchors a row of precision-cast turbine blades, also caHed buckets, which protmde tangentiaHy from the shaft and impart rotation to the shaft when impacted by jets of high pressure steam. Rows of stationary blades are anchored to the steam turbine s outer sheH and are located between the rows of moving rotor blades. 

Fig. 1. Deceleration and penetration curves from dynamic impact tester. Time vs distance penetrated (A) and deceleration (B). Distance between vertical...

Master curves can be used to predict creep resistance, embrittlement, and other property changes over time at a given temperature, or the time it takes for the modulus or some other parameter to reach a critical value. For example, a mbber hose may burst or crack if its modulus exceeds a certain level, or an elastomeric mount may fail if creep is excessive. The time it takes to reach the critical value at a given temperature can be deduced from the master curve. Frequency-based master curves can be used to predict impact behavior or the damping abiUty of materials being considered for sound or vibration deadening. The theory, constmction, and use of master curves have been discussed (145,242,271,277,278,299,300). 

Fig. 2. Typical impact energy vs adhesion (10 is high, 0 is no adhesion) curve obtained from the mean break height test carried out at 2I°C with a 2.27 kg ball on 30-cm square laminates. Mean break height dramatically declines when adhesion is at high levels.

Proportion of Hard Segments. As expected, the modulus of styrenic block copolymers increases with the proportion of the hard polystyrene segments. The tensile behavior of otherwise similar block copolymers with a wide range of polystyrene contents shows a family of stress—strain curves (4,7,8). As the styrene content is increased, the products change from very weak, soft, mbbedike materials to strong elastomers, then to leathery materials, and finally to hard glassy thermoplastics. The latter have been commercialized as clear, high impact polystyrenes under the trade name K-Resin (39) (Phillips Petroleum Co.). Other types of thermoplastic elastomers show similar behavior that is, as the ratio of the hard to soft phase is increased, the product in turn becomes harder. 

Comparison Data—Plate Dryers Comparative studies have been done on products under both atmospheric and vacuum drying conditions. See Fig. 12-79. These curves demonstrate (1) the improvement in drying achieved with elevated temperature and (2) the impact to the drying process obtained with vacuum operation. Note that cui ve 4 at 90°C, pressure at 6.7 kPa absolute, is comparable to the atmospheric cui ve at 150°C. Also, the comparative atmospheric cui ve at 90°C requires 90 percent more diying time than the vacuum condition. The dramatic improvement with the use of vacuum is important to note for heat-sensitive materials. 

FIG. 12-79 Plate dryer drying curves demonstrating impact of elevated temperature and/or operation under vacuum. (Krauss Maffei.)... 

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