Energy impacts

Fig. 2 X-ray refraction topographs of a series of /OyPOj/s samples of different impact energies. The total damage of the laminates is characterized by addition of all debonded layers of0° and 90° fiber direction.

Fig. 3 Refraction values of both (0°+ 90°) fiber directions with respect to impact energy per layer. The fiber/matrix debonding of CFRP laminates correlates significantly to the impact energy per volume (energy density).

Electron-impact energy-loss spectroscopy (EELS) differs from other electron spectroscopies in that it is possible to observe transitions to states below the first ionization edge electronic transitions to excited states of the neutral, vibrational and even rotational transitions can be observed. This is a consequence of the detected electrons not originating in the sample. Conversely, there is a problem when electron impact induces an ionizing transition. For each such event there are two outgoing electrons. To precisely account for the energy deposited in the target, the two electrons must be measured in coincidence. 

Janes J 1993 Mass seiected ion anguiar impact energy distributions at the powered eiectrode in CF reactive-ion etching J. Appl. Phys. 74 659-67... 

Impact Energy Absorption. This quantity, often incorrecdy called impact resistance or impact strength, is measured in terms of the work requked to break a standard specimen the proper unit is joule. 

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.

The same researchers proposed that a relationship of impact energy E to crystallizer variables must include the mass of the impacting crystal rotational velocity of the impeller providing mixing CO, and the fraction of the available energy actually transmitted to the crystal S ... 

Deviations from Rutherford cross-sections are also found for heavy projectiles at lower impact energies, when the projectile can bind inner shell electrons which screen the nuclear charge. These deviations are usually small and can easily be taken into account by use of a theoretical correction [3.160]. 

Figure 10.6. (a) Indentation nanohardness of silver/chromium multilayers and single films of the constituent metals, as a function of depth affected by plastic deformation, (b) Charpy impact energies, a measure of fracture toughness, of three materials, as a function of test temperature they are mild steel, ultrahigh-carbon steel and a composite of the two kinds of steel (courtesy Dr. J. Wadsworth) (Fig. 10.6(b) is from Kum et at. (1983)). 

XNBR (wt%) PS (wt%) OPS (wt%) Impact energy (J) Peak load (N) Ductile ratio... 

However, a substantial improvement in impact energies of PP-NBR blends with GMA or IPO functionalized PPs is observed. The PP-NBR blends went through a brittle-ductile transition as the concentration of the functionalized PPs in the matrix phase reached a leveling off at 13 wt% in the case of IPO functionalized PP and 25 wt% in the case of GMA functionalized PP. Up to a ten-fold improvement in impact energy was observed when the brittle-ductile transition was reached. 

Figure 10 Effect of different functionalized PPS on the impact energy of PP-NBR blends, B-HPMA, -GMA, A-TBAEMA, D-HEMA, O-IPO, and A-DMAEMA. Source Ref. 73.

Fiber/matrix Coupling agent Tensile strength Increase in properties [%] Young s Compression modulus strength Impact energy... 

The impact energy generated by each piston as it changes direction is clearly visible in the vibration profile. Since all pistons complete a full cycle each time the crankshaft completes one full revolution, the total energy of all pistons is displayed at the fundamental (lx) and second harmonic (2x) locations. 

Another configuration, called an unbalanced design, has piston orientations that are neither in-phase nor 180° out-of-phase. In these configurations, the impact forces generated as each piston changes direction are not balanced by an equal and opposite force. As a result, the impact energy and the vibration amplitude are greatly increased. 

Horizontal Figure 44.38 illustrates horizontal mechanical looseness, which is also common to machine-trains. In this example, the machine s support legs flex in the horizontal plane. Unlike the vertical looseness illustrated in Figure 44.37, gravity is uniform at each leg and there is no increased impact energy as the leg s direction is reversed. 

Small and long specimens of tensile bar shape specimens have their major change in dimensions in the necked-down section. The specimen is mounted between a pendulum head and crosshead clamp on the pendulum of an impact tester. The pendulum is released and it swings past a fixed anvil that halts the crosshead clamp. The pendulum head continues forward, carrying the forward portion of the ruptured specimen. The energy loss (tensile impact energy) is recorded, as well as whether the failure appeared to be of a brittle or ductile type. 

Generic Material Type Trademark Grade Izod Impact Energy for 0.318 cm (0.125 in.) thick, Notched Specimens, J/m Tensile-impact Short Specimens, kJ/m2 Energy Long Specimens, kJ/m2... 

Izod nothed impact energy Impact resistance of plastics and electrical insulating materials ASTM D-256-91 Pendulum impact tester type 5102, Zwick... 

It should be mentioned that fire retardant-polypropylene has higher impact energy than polypropylene without HBCD and this improved impact energy resulting from the addition of fire retardant is a rare phenomenon. Usually the addition (15-25%) of low molecular components decreases the high impact properties of plastics although we know that HIPS flame-retarded with decabromodiphenyl oxide (DECA), for example, has almost the same impact energy as non-retarded HIPS (Table 5). 

Impact energy can be further improved by the use of impact modifiers. In this approach the combination of impact improvement and fire retardant enhancing is of special interest (ref. 5). Figure 5 demonstrates this effect in ABS flame-retarded with commercial FR-1208 (octabromodiphenyl oxide) and with the proprietary FR-T6385. 

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