Charpy pendulum

Figure 8.13 Dependence of two estimates on the impact strength on the amount of PDMS in PDMS-modified Si02 glasses.144 The impact strengths were obtained from (O) the Charpy pendulum impact test (A) the falling-weight impact test.

These were carried out on test bars, 55x10x10 mm., with a Mesnager notch of 2 mm. depth, using a 30 kg. m. charpy pendulum of the Conservatoire des Arts et Metiers. 

Bars 55x10x10 mm. with a 2-mm. round notch. Apparatus 30 kg. m. Charpy pendulum. 

A new part to ISO 179 is under preparation that will cover the instrumentation of the Charpy pendulum so that force-time (and by integration, force-dcflection) curves can be obtained. This allows for a fuller characterization of the impact behavior of the plastic than can be derived from only the energy to break of the typical test. There has been an instrumented version of the falling weight impact test (see later in this section) for several years and the same principles apply to both. 

Besides strength and stiffness, impact properties of a material are of great practical relevance. Here the time scale of loading is in the order of milliseconds, while strength properties are tested in seconds or even minutes. Therefore, elongation from tensile experiments, which is often used as a measure of ductility, can oidy be of limited interest and standard impact experiments, like Izod or Charpy pendulum methods, have been developed. 

JSA (2005) Method for Charpy Pendulum Impact Test of Metallic Materials, JIS Z 2242, Japanese Standards Association, Tokyo. 

ISO (2009), Metallic materials - Charpy pendulum impact test - Part 1 Test method, ISO 148-1 2009, International Organization for Standardization, Geneva. 

Figure 9.14 illustrates some improvement in impact strength in such composites. Specifically, impact strengths of some PDMS-SiOj samples were determined by the Charpy pendulum test and by the falling-weight test. The samples investigated were PDMS-modified SiOj and SiOj/TiOj... 

Charpy pendulum adapted to test lap joints (a) overall view (b) fixation of the specimen on the hammer (From Goglio and Rossetto [2008], copyright Elsevier)... 

The Charpy pendulum impact test is most commonly employed in the European continent. Both the standard test bar and the small standard test bar are specified in the Clerman Standard DIN 53453. The sample is notched and is supported horizontally against the stops at either end. The pendulum striker hits... 

Impact resistance measurements were performed on a dog-bone shape specimen, with a ATS FAAR Charpy pendulum, according to the ASTM D 256 method. 

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