Use of instrumented charpy tests to determine onset of upper-shelf energy
Use of instrumented charpy tests to determine onset of upper-shelf energy The Charpy V-notch (C/sub v/) upper-shelf energy is usually defined as that temperature range in which the surface of the C/sub v/ specimen exhibits an appearance indicative of a 100 percent ductile fracture. In an attempt to avoid the need for interpretation, the selection of the C/sub v/ upper-shelf energy is based on the results from an instrumented impact test which provides a permanent record of the load-deflection history of a C/sub v/ specimen during the testing sequence. In the brittle-ductile transition temperature regime, a precipitous drop in the load trace occurs. The amount of the drop decreases at higher temperatures until it is zero, and the zero-drop-in-load temperature is identical to the onset of the C/sub v/ upper shelf. This relationship between the drop in load and energy in an instrumented impact test provides incontestable assurance that the C/sub v/ upper shelf has been obtained. This relationship between drop in load and temperature permits a prediction of the onset of the upper-shelf temperature with as few as two instrumented impact tests. It is also shown that nil-ductility temperature (NDT) (determined by the drop-weight test) is more »
Enter terms in the toolbar above to search the full text of this document for pages containing specific keywords.