Tensile Impact Test with Pendulum Impact Tester

What is a Tensile pendulum impact test?

A test method for determining energy required to fracture a specimen under shock tensile loading. Typically executed on a pendulum testing machine, the tensile impact strength test was originally developed to overcome the deficiencies of flexural (both Izod and Charpy) impact test. All the test variables that have a high effect on the results, such as notch sensitivity, toss factor and specimen thickness, are eliminated in the tensile impact test. This test, on the contrary of Izod and Charpy types, which are limited to thick specimen only, allows to determine the impact strength of very thin and flexible specimens.

How is a Tensile pendulum impact test performed?

There are two different test configurations. One consists in a specimen-in-head kind of setup (ISO 8256 method B), where the specimen is attached directly to the pendulum hammer. The energy to break by impact is determined by the kinetic energy value extracted by the pendulum in the process of breaking the specimen. The test setup requires to mount one end of the specimen on the hammer and the other end has to be gripped inside a crosshead member, which travels together with the pendulum until the impact instant. As long as the machine bas is rigid enough to prevent vibrations, the energy lost by the bounce of the crosshead in the opposite direction can be easily calculated.

The second test configuration is a specimen-in-base setup (ISO 8256 method A). The specimen is clamped in a specimen vice supported by the frame of the pendulum and it is broken by the impact between pendulum and crosshead member, which is always clamped on the other extremity of the specimen.

The following figure illustrates the most common specimen-in-base impact configuration.
Tensile Impact Test Glossary Diagram
Hammer energies are available from 0.5 - 50 J (0.37 - 36.9 ft-lbs) depending on the type of the test and impact velocities of 2.9 m/s and 3.8 m/s. The tensile impact test introduces strain rate as an important test variable and many researchers have demonstrated that the tensile impact test results correlate better with the actual field failures than Izod or Charpy impact test analysis.
Related Content

3400 Series - Affordable Testing Solutions

Instron 3400 Series Universal Testing Systems for Tensile, Compression, Bend, and other material property tests.

6800 Series Premier Testing Systems Brochure

Instron 6800 Series Universal Testing Systems provide unparalleled accuracy and reliability. Built on a patent-pending Operator Protect system architecture with an all-new Smart-Close Air Kit and Collision Mitigation features, the 6800 Series makes materials testing simpler, smarter, and safer than ever before.

Bluehill Universal Brochure

Bluehill Universal Software is built from the ground-up for touch interaction and an intuitive user experience. Discover simpler and smarter testing with features such as pre-loaded test methods, QuickTest in seconds, enhanced data exporting: and Instron Connect – a new feature that provides a direct communication link to Service. Users of previous versions of software such as Bluehill 2 and Bluehill 3 can easily upgrade to the newest version of Bluehill.