Document Details


Title:
OPERATION REDWING-PROJECT 8.4: THERMAL EFFECTS ON STRENGTH OF AIRCRAFT STRUCTURAL SANDWICH-TYPE PANELS (DELETED)
Author(s):
JULIAN, A [COOK RESEARCH LABORATORIES, COOK ELECTRIC CO, CHICAGO, IL]; EVES, C E [COOK RESEARCH LABORATORIES, COOK ELECTRIC CO, CHICAGO, IL]
Subject Terms:
REDWING PROJECT; THERMAL RADIATION; RADIATION EFFECTS; AIRCRAFT; DAMAGE; RESEARCH PROGRAMS
Document Location:
Location - NNSA/NSO Nuclear Testing Archive Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - CIC@NV.DOE.GOV
Document Type:
REPORT
Publication Date:
1956 Jul 01
Declassification Status:
Sanitized
Document Pages:
0056
Accession Number:
NV0051060
Document Number(s):
WT1341EX
Originating Research Org.:
COOK RESEARCH LABORATORIES, COOK ELECTRIC CO, CHIC
OpenNet Entry Date:
1994 Aug 26
Description/Abstract:
THIS PROJECT WAS CONDUCTED TO DETERMINE THE EFFECTS OF THERMAL RADIATI ON ON SANDWICH-TYPE AIRCRAFT STRUCTURAL PANELS. TEST PANELS OF VARIED CONSTRUCTION MATERIALS AND FACING THICKNESS WERE SUBJECTED TO TRANSIE NT HEAT PULSES IN UNLOADED AND PRESTRESSED CONDITIONS TO DETERMINE IF ANY CHANGE IN STRUCTURAL INTEGRITY COULD BE NOTED. INITIAL SPECIMENS WERE INSTRUMENTED FOR MEASUREMENT OF TEMPERATURE-TIME HISTORY AT THE C ORE-TO-FACING BOND AND EXPOSED TO THERMAL RADIATION DURING OPERATION R EDWING. FORTY UNLOADED PANELS AND TWO FJ-4 ELEVATORS WERE EXPOSED AT STATION 840.01 ON ISLAND GEORGE DURING SHOT CHEROKEE. SMALL GROUPS OF SIMILAR SPECIMENS WERE MOUNTED ON THE PROJECT 5.8 AIRCRAFT AND EXPOSE D DURING THE TEST SERIES. RECORDED PEAK TEMPERATURE RISES AT THE GROU ND STATION WERE IN THE RANGE FROM [ ] OF THE EXPECTED AN D DESIRED RANGE. THESE LOW TEMPERATURES ARE ATTRIBUTED TO OBSCURATION OF THE TEST ARRAY BY SMOKING OF THE GRAY-PAINTED SAMPLES AT RELATIVEL Y LOW TEMPERATURES, AND A MUCH-HIGHER RATE OF HEAT CONDUCTIVITY TO THE CORE AND REAR FACING THAN WAS ORIGINALLY EXPECTED. OBVIOUS PHYSICAL SEPARATION OF THE FACING-TO-CORE WAS NOTED ONLY IN SAMPLES OF 5-PLY (A PPROXIMATELY 0.016-INCH) AND 7-PLY (APPROXIMATELY 0.025-INCH) PHENOLIC FACE ON BALSA CORE, AS INDICATED BY MARKED CONVEXITY OF THE SEPARATED AREAS. RESULTS OF COMPARATIVE POST-EXPOSURE MECHANICAL TESTS ON FIEL D-EXPOSED, ALUMINUM-FACING SAMPLES SHOWED NO NOTEWORTHY CHANGE IN STRE NGTH CHARACTERISTICS AS A RESULT OF THE RADIANT EXPOSURE. HOWEVER, TE STS CONDUCTED ON SIMILAR SPECIMENS PULSE-HEATED IN A RESTRAINED AND PR ESTRESSED CONDITION SHOED THAT FAILURE WILL OCCUR AT TEMPERATURES WELL WITHIN THE RANGE OF THAT DEVELOPED IN THE FIELD-EXPOSED SPECIMENS. I NITIAL RESULTS OF THE LOADS PROGRAM, WHICH IS STILL IN PROGRESS, SHOWE D THAT 0.020-INCH ALUMINUM FACING ON BALSA-CORE SPECIMENS WILL FAIL AT TEMPERATURE RISES OF APPROXIMATELY 200 DEGREES F WHEN SUBJECTED TO RE LATIVELY LOW STRESSES DURING THE HEATING CYCLE. FINAL RESULTS OF THIS LOADS PROGRAM WILL BE PUBLISHED AT A LATER DATE UNDER BUAER CONTRACT NOA(S) 56-367C, AND BUAER PROJECT TED NAM AD 4002. ANALYSIS OF THE RE CORDED FIELD-TEMPERATURE RESPONSE AND SUBSEQUENT LABORATORY PULSE-HEAT ING TESTS LED TO THE NECESSITY FOR A COMPLETE STUDY OF THE HEAT-TRANSF ER CHARACTERISTICS OF SANDWICH CONSTRUCTION. AS A RESULT OF THIS STUD Y, A MATHEMATICAL FORMULATION HAS BEEN DERIVED. WHEN THESE FORMULAS W ERE PROGRAMED FOR DIGITAL COMPUTER USE, ACCURATE RESULTS WERE OBTAINED . THIS PROGRAM CAN BE USED WITH CONFICENCE TO PREDICT THERMAL RESPONS E TO HEAT PULSES FROM NUCLEAR WEAPONS OR LABORATORY HEAT SOURCES, AND COULD ALSO BE USED IN ESTABLISHING MATERIAL CRITERIA FOR SANDWICH STRU CTURES HAVING SUPERIOR THERMAL TOLERANCE.


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