Impact beam testing

We test the impact resistance of polymer plaques using the configuration shown in Fig. 8.8. We subject circular injection molded plaques to the shock of a falling weight with a hemispherical impacter. This test is also known as the Dart Drop Test . Samples can fail in a brittle or a ductile manner. Brittle samples often shatter. Ductile samples can split or a small disk may be punched out of their center. This test provides results that are analogous to those obtained from un-notched impact beam testing. 

Tensile impact testing is used to determine the impact resistance of samples that are too thin or too flexible for impact beam or impact plaque testing but cannot be considered films. It involves strain rates that are intermediate between those used for impact beam testing and those used for conventional tensile testing. This procedure is performed according to ASTM Method D 1822. 

Describe how we perform toughness testing on polymers with both the impact beam and the falling weight methods. Explain the different manners by which an amorphous polymer will fail above and below its glass transition temperature. 

The impact toughness of a material, as measured by a flexed-beam test on a notched specimen, depends on the thickness of the specimen and the radius of the notch, and therefore cannot be considered a material property. Furthermore, the transition from predominantly plane-stress to predominantly plane-strain is unpredictable when complex geometries are encountered in structural components. Because this transition can create imexpected and catastrophic failures, some polymers normally considered to be very tough and ductile may benefit from impact modification. The modified versions are less sensitive to geometric variations. 

Regarding the measurement of the adhesive fracture energy, Gc, under impact (or, in general, dynamic) conditions, the double cantilever beam test and the tapered double cantilever beam test (O Fig. 21.15) must be adapted to account for the effect induced by the loading rate. Indeed, in statics the base for the measurement is the formula (Williams 1984)... 

This paper deals with the control of weld depth penetration for cylinders in gold-nickel alloy and tantalum. After introducing the experimental set-up and the samples description, the study and the optimization of the testing are presented for single-sided measurements either in a pulse-echo configuration or when the pump and the probe laser beams are shifted (influence of a thermal phenomenon), and for different kind of laser impact (a line or a circular spot). First, the ultrasonic system is used to detect and to size a flat bottom hole in an aluminium plate. Indeed, when the width of the hole is reduced, its shape is nearly similar to the one of a slot. Then, the optimization is accomplished for... 

Epoxy acrylate (Ebecryl 3700, 50%) combined with 25% TMPTA, 25% I BOA and with DIBF-OPPI-DIDMA pigment and FC-171 as above was also used to coat panels. These panels showed no removal of coating in the cross hatch adhesion test. With 6.8j there was no loosened coating on the frontal impact surface, and only 30% was loosened on the back surface. Five hundred grams were required to scratch to bare metal with the balanced beam. Performance was... 

The Charpy test and the Izodtest are both pendulum-type impact tests. The difference between these two tests is essentially the orientation of the sample. In the Charpy test, or simple-beam method, the sample is supported at both ends, but is not held down, as shown on the left in Figure 15.30. In the Izod test, or cantilever beam method, the sample is supported on one end in a vice, as shown on the right in Figure 15.30. In both tests the sample is at the bottom of the pendulum arc and the amount of energy absorbed by the sample is measured. 

Ion beams are useful to simulate the environment in space, where semiconductor devices are exposed to high-energy heavy-ion impact. Incorrect operation of semiconductor devices such as single-event upset results from the heavy-ion irradiation. The cocktail ion families of MjQ = 4 and 5, available at the JAERI AVF cyclotron facility [24], are frequently utilized to investigate the tolerance of the semiconductor devices to the radiation, and to survey highly radiation-tolerant semiconductor devices appearing in the market. Efficiency of the radiation-tolerance testing for thousands of kinds of semiconductor devices has been totally improved by the cocktail acceleration technique. 

Lahanier et al. Cited in Janssens K (2005) A survey of the recent use of X-ray beam methods for non-destructive investigations in the cultural heritage sector, Cultural Heritage Conservation and Environment Impact Assessment by Non-Destructive Testing and Micro-analysis, Van Grieken R, Janssens K (Eds) AA Balkema Publishers, London, pp. 265-308. 

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