Methods pendulum

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). 

There are other, less commonly used, methods for measuring hardness. One is an impact method in which an indenter is dropped from a known height onto a specimen, and either the size of the indentation, or the coefficient of restitution, is measured. Another is the pendulum method in which a rocking pendulum is applied to a specimen surface. The damping of the pendulum s oscillations is a measure of the hardness. Still another is Moh s scratch method in which the ability of one specimen to scratch another is observed. These methods are described in various books (McColm, 1990), but only the... 

ISO 4663 1986 Rubber - Determination of dynamic behaviour of vulcanizates at low frequencies - Torsion pendulum method... 

A number of pendulum methods have been standardised over the years but the present ISO standard, ISO 46628 is not based on any particular pendulum design but on giving limits for various parameters. A few years ago, extensive interlaboratory investigations were carried out within TC45 to determine the effect of pendulum parameters on measured resilience and the conclusions from those investigations has led to the present standard. 

Ashly, " Brittle Fracture of Ball Propellant , Frankford Arsenal Rept No R-1360,Philadelphia, Pa(1956)(Conf) ll)J.P.Frankel,"Principles of the Properties of Materials",McGraw-Hill,NY (1957),184-5(A brief description of a Swinging Pendulum Method for testing brittleness) 12) 12)ASTM Standards,Part 9,Philadelphia,Pa(l958), pp 355-60 13)US Federal Specification L P... 

Torsion pendulum method for determining crystallinity and void content of tetrafluoroethylene resins. ASTM Bull. No. 242, 80—82 (1959c). 

One of most popular techniques for dynamic mechanical analysis is the torsion pendulum method. In a modification of this method designed to follow curing processes, a torsion bar is manufactured from a braid of fibers impregnated with the composition to be studied this is the so-called torsional braid analysis (TBA) method.61 62,148 The forced harmonic oscillation method has been also used and has proven to be valuable. This method employs various types of rheogoniometers and vibroreometers,1 9,150 which measure the absolute values of the viscoelastic properties of the system under study these properties can be measured at any stage of the process. The use of computers further contributes to improvements in dynamic mechanical analysis methods for rheokinetic measurements. As will be seen below, new possibilities are opened up by applying computer methods to results of dynamic measurements. 

ISO 4662 details testing by the pendulum method. There are a number of different machines that conform to the specifications for impacting mass, velocity, and the apparent strain energy density. The types of suitable instruments mentioned in the specification include the Liipke, Schob, and Zerbini. Some modern instruments have electronic outputs giving either digital or printed results. 

Part 1 General guidance Part 2 Torsion pendulum methods... 

G Torsion pendulum method (Nielsen, 1962) (measurement of frequency of oscillations and rate of damping, at different temperatures) Measurement of speed of shear wave (Schuyer et al., 1954, Hartmann, 1980) G = pu2sh... 

An explosion of HE may also be initiated by severe shock. Sensitivity of explosives to shock may be measured in several ways, such as the impact pendulum method and the drop test. In the impact pendulum test, a heavy pendulum swings down over a sample... 

The viscosity of the melts of the KF-K2M0O4-B2O3 system has been measured by Silny et al. (1995) using the computerized torsion pendulum method. The viscosity of... 

One of the most used and also most suitable methods of viscosity measurement of molten salts is the torsional pendulum method, which could be developed by the introduction of automatic and computational methods. The pendulum is realized in general by an arbitrary rotational body suspended from a torsional wire. However, the exact... 

Generally, the operative frequency range for the torsional pendulum method is 0.01 to 50 Hz, the upper limit of the frequency defined by the dimensions of the oscillatory frequency relative to the dimensions of the sample. At higher investigative temperatures, the polymeric materials may undergo extensional deformation (creep) due to the weight of the inertia bar. Under such circumstances, a modified torsion pendulum apparatus may be used in which an inertia disk is attached directly onto the end of the sample (12). In addition, this method is frequently employed to measure the torsion modulus at low frequencies. 

Figure 7-13. Damped pendulum method for measurement of friction. A view of the moving specimen in the cradle of the fixed specimens. After Y. Tamai [13].

BS 2782 Method 306A, Impact Strength (Pendulum Method), London (1970). 

ASTMD 1922-03. Standard Test Method for Propagation Tear Resistance of Plastic Film and Thin Sheeting by Pendulum Method. 

Previously, the major drawback to the simple torsion pendulum method was that it could not be used while the hber is immersed in liquids because of the damping effect of the liquid. However, Wolfram and Albrecht [83] have devised an ingenius scheme to overcome this obstacle by inserting the hber into a small glass capillary tube, thus permitting the torsional properties of hair hbers (and other hbers) to be measured in both air and liquids. Other methods are available [79,80,84] for measurement of the rigidity of hbers immersed in liquids. For additional details, see the references indicated and the texts by Meredith and Hearle [84] and Morton and Hearle [76]. 

The torsional modulus for human hair by the pendulum method is lower than either the stretching or the bending modulus at 60% to 65% RH. However, water has a greater effect on torsional properties than on either stretching or bending for both human hair and wool hber (see data describing these three different elastic moduli in Table 8-5 and 8-6). 

ASTM D1922, Propagation tear resistance of plastic film and thin sheeting by pendulum method. 1994,... 

ISO 4674 2. Determination of tear resistance. Part 2, Ballistic pendulum method, 1998. 

ISO 9290. 1990. Textiles—woven fabrics -Determination of tear resistance by the falling pendulum method. 

Propagation Tear Resistance of Plastic Film and Thin Sheeting by Pendulum Method, Elmendorf Tear. Primary Film Test Method ASTM D1922. Tear strength is the force necessary to eontinue tearing a sample after a nick has been made it is reported in grams. 

---