The Latest in Pyroshock Testing TechniquesJanuary 6, 2010
by Vesta I. Bateman, Chair, IEST Working Group DTE032
The IEST Recommended Practice on pyroshock testing has been revised and updated to reflect advances in the art of pyroshock testing and to address common problems related to data accuracy in the pyroshock community. The key changes to IEST-RP-DTE032: Pyroshock Testing Techniques are described here.
New definitions for near-field pyroshock, mid-field pyroshock, and far-field pyroshock adopted by IEST-RP-DTE032.2 are consistent with the definitions given in MIL-STD-810G, Method 517, as shown in the table and the spectra definitions below. The definitions and table values are quantified in terms of shock response spectra (SRS). The SRS, with an appropriate damping value, is the most widely used tool to analyze pyroshock data and is calculated using acceleration measurements near components and subsystems that must be qualified separately. The Jet Propulsion Laboratory will be revising NASA-STD-7003 during the coming year, and the current NASA values for near-field, mid-field, and far-field pyroshock are also shown in the table.
A near-field pyroshock test requires frequency control up to and above 10 kHz for amplitudes greater than 10,000 g. A pyrotechnically excited simulation technique is usually appropriate, although in some cases a mechanically excited simulation technique may be used.
A mid-field pyroshock test requires frequency control from 3 kHz to 10 kHz for amplitudes less than 10,000 g. A mechanically excited simulation technique other than shaker shock is usually required.
A far-field pyroshock test requires frequency control no higher than 3 kHz for amplitudes less than 1,000 g. A shaker shock or a mechanically excited simulation technique is appropriate.