Impact testing pendulum

Tensile and flexural properties were studied with an Instron 4204 testing machine. Tensile tests were performed on the drawn strands at a test speed of 3 mm/ min, while three-point-bending tests (ISO 178) at a speed of 5 mm/min were applied to the injection molded specimens. Charpy impact strength was measured of the unnotched samples with a Zwick 5102 pendulum-type testing machine using a span of 70 mm. The specimens (4 X 10 X 112 mm) used for three-point-bending tests were also used for the impact tests. It should be noted that neither the tensile tests for the strands nor the impact tests were standard tests. The samples were conditioned for 88 h at 23°C (50% r.h,) before testing. 

Methods employed to determine the impact resistance of plastics include pendulum methods (Izod, Charpy, tensile impact, falling dart, Gardner, Dynatup, etc.) and instrumented techniques. In the case of the Izod test, what is measured is the energy required to break a test specimen transversely struck (the test can be done either with the specimen notched or unnotched). The tensile impact test has a bar loaded in tension and the striking force tends to elongate the bar (Chapter 5, Impact Strength). 

The popular Izod impact tester can use different size specimens depending on the type of plastic and their method of fabrication. The specimen is usually 1/8 in. x l/2 in. x 2 in. other sizes are also used. Specimens can be notched or unnotched. A notch is cut in a specified manner on the narrow face of the specimen. The sample is clamped in the base of a pendulum testing machine so that it is cantilevered upward with the notch facing the direction of impact. The pendulum is released, and the force expended in breaking the sample is calculated from the height the pendulum reaches on the follow-through. The speed of the pendulum at impact is controlled. 

Figure 8.7 Schematic Illustration of a pendulum type impact testing device...

Pendimethalin, 73 319 Pendulum impact tests, 19 580 Penetrating particle size, in depth filtration theory, 11 340-341... 

The impact testing machine shown in Figure 15.29 measures the arc, or angle, through which the pendulum swings and converts this measurement to the energy needed to break the specimen. This energy is reported in either foot-pounds (fit-lbs) or Newton-meters (N-m.), also called joules. 

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. 

The Izod and Charpy impact tests are mostly used. A defined pendulum strikes the specimen sample, notched or un-notched, clamped with a defined device. The absorbed energy is calculated and expressed ... 

Fatigue resistance increases with the [PU] up to 50Z, while energy absorption determined from dynamic properties and pendulum impact tests varies directly with the [PU], The micromechanism of failure Involves the generation of discontinuous growth bands associated with shear yielding rather than crazing. 

FIGURE 14.16 Pictorial description of Charpy (a) and Izod (b) pendulum impact tests. 

Impact-Friction Pendulum Test. See Vol 1, p XVII and p A354, Footnote... 

Lead Block and Copper Cylinder Compression Tests (113-15) Ballistic Pendulum Test (115-16) Fragmentation Test (Geschoss-Splitter Probe (118) Impact Test by Falling Weight (118-20) Deflagration Point (Verpuf-fungstemperatur) (120) Friction Test (120-21) Rifle Bullet Test (Beschussprobe) (121)... 

Power by Trauzl Test (142-45), by Compression Test (Ensayo por recalcado) (145-46) and by Ballistic. Pendulum (146) Fragmentation Test (148-49) Impact Test (Ensayo con un pilon) (150-53) Temperature of Deflagration (153) Friction Test (Ensayo de rozamiento) (153-54) Rifle Bullet Test (Ensayo de impacto) (154)... 

W() Kirk Othmer, Vol 8(1952), pp 654-57 (Section on Testing Exolosives which includes Impact Tests, Explosion Temperature Tests, Sensitivity to Initiation, Pendulum Friction Test, Rifle Bullet Test, Sand Test, Rate of Detonation Determination, Ballistic Pendulum Test, Trauzl Lead Block Test,... 

Impact-Friction Pendulum Test is briefly described, p A354, Note d), under Ammonium Nitrate Ref Spencer Chemical Co, "Safety Data, Kansas City, Mo(l960)... 

Nechiporenko41 used a novel approach of repeated impact testing to obtain fatigue life under circumstances that would be relevant to tyres in quarries. He used a Schob pendulum with automatic delivery and counting of impacts, and needed only tests at two energies with up to 150 blows to give a rapid test. 

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