ASTM D3763, ASTM D7192, ISO 6603, ISO 7765 Multiaxial Impact Test

Scope:

ASTM D3763 and ASTM D7192 tests determine toughness, load-deflection curves, and overall energy absorption of impact events. Different speed values are applied to simulate actual impact values at high-speed conditions. This multiaxial impact test evaluates full force and energy curves for the impact, usually lasting for a millisecond. This test uses a “Tup” which incorporates an impact head and a load cell. The data obtained specifies appropriate materials for applications involving impact. Sometimes, the multiaxial impact test measures the effect of various environmental factors and secondary finishing operations on plastic impact properties. 

Sometimes it is more appropriate to test materials at temperatures that simulate the intended end-use environment, such as thermoplastics and some other materials that show lower impact strength at lower temperatures.

Test Procedure:

For ASTM D3763 and ASTM D7192 tests, instron Dynatup 9250 HV High-Speed Impact Tester is usually used for testing. The instrumented impact tester comprises a thermal chamber for testing specimens at high and low temperatures. Transfering the specimens from an oven or freezer just before the testing is not required. This ensures better control and consistency of test results at elevated and reduced temperature values. The high-speed impact tester also provides a greater range of impact velocities, say from 2.2 meters/second (5 mph) to 6.6 meters per second (15 mph) and up to 20 meters per second (45 mph). The specimen is fixed onto the testing platform. A tup is attached to the crosshead which is first raised to the required height and then released at a specified speed to cause an impact. Then the instrument records a load-deflection curve.

Reduced temperature test

To attain temperature equilibrium specimens are conditioned in a freezer at the specified temperature for at least 6 hours. Next, the thermal chamber at the base of the impact equipment is brought to the required temperature before testing starts. A specimen is then moved from the freezer and clamped onto the test platform. After the chamber regains equilibrium, the crosshead is released to impact the specimen.

Specimen size:

Generally, 4 × 4 inches plaques or 4 inches diameter disks are used as specimens. However, any size or shape that fits into the impact tester and sometimes actual parts may also be tested in this method.

Result:

Data is provided as aload-deflection curve. In addition, several data values related to total energy and toughness are calculated, including energy at maximum force, maximum force, and total energy to break.

Conclusion:

ASTM D3763 and ASTM D7192 provide standard test methods for high speed puncture multiaxial impact.