Pendulum impact tester

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

In pendulum-impact methods energy expended by a standard pendulum-impact tester to break a test specimen... 

Figure 2-38. Pendulum impact tester. (Courtesy of CEAST U.S.A. Inc.)...

Specimens from the parts were impact tested in a pendulum impact tester with maximum fracture energy equal to 4J. Figure 2 shows the locations where impact specimens were taken from the parts (left), and the positioning of the specimens in the impact tester for sideways impact (right). Ten specimens were tested for each combination of material... 

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. 

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. 

Indentation hardness determinations were performed in dynamic mode ( 1500 mm/sec impact speed) using a pendulum impact device and in quasistatic mode ( 0.008 mm/sec impact speed) with a custom-built indentation tester. The spherical indenters were of 2.54 cm diameter and 65.6 g mass, and the pendulum length was 92.3 cm with a release angle of 30°. Quasistatic indentation forces were selected to produce indentations of a similar size to the dynamic indentation test (1.5 to 2.0 mm radius). The compact indentations were measured using a white light interferometer (Zygo Corporation, Middlefield, Connecticut, U.S.A.) and the dent depth, dent diameter, apparent radius of curvature, and pendulum initial and rebound heights were used to calculate the indentation hardness of the compacts. 

In the Charpy impact tester the specimen is mounted on a span support and struck centrally with a swinging pendulum (see Fig. 2). The results are expressed in terms of breaking energy per nnit of cross-sectional area. 

Figure 3-77. A schematic of an Izod impact tester. A free-swinging pendulum strikes a vertically supported specimen held in a clamp a notched specimen is located so that its notch is level with the top of the clamp and is facing the pendulum, per ASTM D 256.

The most common impact tester is a pendulum. A pendulum tester is divided into a beam (Charpy) type and a cantilever beam (Izod) type according to the way the sample sets. Samples either can have a gap or be without a gap. 

There is a standard method of estimating the hardness of coating materials [210]. Tests are usually made on the basis of the pendulum method (impact tester) relative to the elastic properties of a glass surface, the hardiness of which is taken as unity. Below we present some results 6f hardness tests based on the pendulum method for various paints and enamels [211] ... 

Tensile tests at low to intermediate displacement rates (i.e. 1, 10, 100 and 500 mm/min) were performed by an Instron tensile tester model 4502 equipped with a 1 kN load cell. Temperature in the range from 0°C to 70°C was controlled by an Instron thermostatic chamber model 3119. Tests at the moderately high displacement rate of 60000 mm/min (1 m/s) were carried out at room temperature by an instrumented CEAST impact pendulum in the tensile configuration. Load data were collected at a sampling time of 30 p.s and load vs displacement curves were provided directly by the CEAST software (DAS 4000 Extended Win Acquisition System Ver. 3.30). 

Fig. 8.13 The Charpy impact test (a) the pendulum tester, ASTM 256 and (b) the sample and striking hammer tip. ((a) Reprinted and (b) adapted, with permission from the American Society for Testing and Materials.)...

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