Impact Tests

Impact tests simulate severe conditions for structural failure. The geometry for the Charpy V-notch test results in a high loading rate, stress concentration, and a tri-axial state of stress. Of particular interest is the brittle-to-ductile transition that occurs in low alloy ferritic steels and other body-centered cubic materials.

Charpy V-notch tests are performed on the Dynatup Model 8250 impact machine. The specimen is placed in the machine and the mass is dropped. The impact velocity is determined and load data from the instrumented tup are recorded and plotted vs. time. The maximum load is noted. The data are used to calculate the energy absorbed by the specimen.

The fracture surfaces of the specimens are inspected. Brittle behavior correlates with low energy absorption. Ductile fracture is associated with higher energy absorption.

Aluminum and low-carbon steel notched beams are tested at three temperatures: 0°C (ice water bath), room temperature, and 100°C (boiling water bath). Fracture appearance and impact data are correlated and compared.

Impact tests on polymer plates are conducted on the Dynatup Model 8200 impact machine. The plate is clamped, then the mass is dropped. Analysis is similar to the Charpy test. The load data are used to calculate energy absorbed.

The same temperatures are used. Fracture behavior is noted and correlated with energy data.