Thermal expansion coefficients of a 30% glass fiber filled PEEK pyrotechnic charge holder
Pyrotechnic actuators use hollow cylindrical ceramic or plastic charge holders to electrically isolate the pyrotechnic charge from the actuator case. In a newly developed actuator, 30% glass fiber filled polyetheretherketone (PEEK) was selected as the charge holder material both for its strength and its forming properties. Because the actuators are exposed to significant temperature variations during storage and flight, a determination of the coefficient of thermal expansion, ..cap alpha.., of the charge holders was required to assure success in this, the first electroexplosive device application of PEEK. Of special interest in this project were the questions of whether ..cap alpha.. depends on the direction (with respect to flow in the mold) or on injection pressure. From the test results, the conclusions are: (1) ..cap alpha.. does depend on direction. Its value in the thickness direction is approximately twice that in either the height or circumferential direction. This is probably because the wall thickness, 0.015'', is less than the average fiber length, 0.100'', and the PEEK is, therefore, not acting as a composite in the t direction. (2) Varying the injection pressure over the range of this study has no detectable effect on ..cap alpha... This charge holder is molded into an Inconel actuator case with ..cap alpha.. = 11.4 ..mu..m/m.C. This relatively close match of ..cap alpha..'s between adjacent materials has resulted in no dimensional problems during manufacturing and environmental testing. 1 fig., 1 tab.
- Research Organization:
- Monsanto Research Corp., Miamisburg, OH (USA). Mound
- DOE Contract Number:
- AC04-76DP00053
- OSTI ID:
- 5698228
- Report Number(s):
- MLM-3240(OP); CONF-8503100-5; ON: DE85010805
- Resource Relation:
- Conference: ADPA meeting, Hilton Head, SC, USA, 11 Mar 1985
- Country of Publication:
- United States
- Language:
- English
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