Engineering topics

Baker, Donald J.

Publications and source records attributed to Baker, Donald J..

24 records · Page 2

NASA NTRS1992

Flight service environmental effects on composite materials and structures

NASA Langley and the U.S. Army have jointly sponsored programs to assess the effects of realistic flight environments and ground-based exposure on advanced composite materials and structures. Composite secondary structural components were initially installed on commercial transport aircraft in 1973; secondary and primary structural components were installed on commercial helicopters in 1979; and primary structural components were installed on commercial aircraft in the mid-to-late 1980's. Service performance, maintenance characteristics, and residual strength of numerous components are reported. In addition to data on flight components, 10 year ground exposure test results on material coupons are reported. Comparison between ground and flight environmental effects for several composite material systems are also presented. Test results indicate excellent in-service performance with the composite components during the 15 year period. Good correlation between ground-based material performance and operational structural performance has been achieved.

Dexter, H. Benson↗

NASA NTRS1991

Mechanical property characterization and impact resistance of selected graphite/PEEK composite materials

To use graphite/PEEK material on highly curved surfaces requires that the material be drapable and easily conformable to the surface. The mechanical property characterization and impact resistance results are presented for laminates made from two types of graphite/PEEK materials that will conform to a curved surface. These laminates were made from two different material forms. These forms are: (1) a fabric where each yarn is a co-mingled Celion G30-500 3K graphite fiber and PEEK fiber; and (2) an interleaved material of Celion G30-500 3K graphite fiber interleaved with PEEK film. The experimental results from the fabric laminates are compared with results for laminates made from AS4/PEEK unidirectional tape. The results indicate that the tension and compression moduli for quasi-isotropic and orthotropic laminates made from fabric materials are at least 98 pct. of the modulus of equivalent laminates made from tape materials. The strength of fabric material laminates is at least 80 pct. of laminates made from tape material. The evaluation of the fabric material for shear stiffness indicates that a tape material laminate could be replaced by a fabric material laminate and still maintain 89 pct. of the shear stiffness of the tape material laminate.

Baker, Donald J.↗

NASA NTRS1990

Evaluation of composite components on the Bell 206L and Sikorsky S-76 helicopters

Progress on two programs to evaluate structural composite components in flight service on Bell 206L and Sikorsky S-76 commercial helicopters is described. Forty ship sets of composite components that include the litter door, baggage door, forward fairing, and vertical fin have been installed on Bell Model 206L helicopters that are operating in widely different climates. Component installation started in 1981 and selected components were removed and tested at prescribed intervals over a ten year evaluation. Four horizontal stabilizers and eleven tail rotor spars that are production components on the S-76 helicopter were tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, materials used to fabricate the components were exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. Results achieved from 123,000 hours of accumulated service on the Bell 206L components and 53,000 hours on the Sikorsky S-76 components are reported. Seventy-eight Bell 206L components were removed and tested statically. Results of seven years of ground exposure of materials used to fabricate the Bell 206L components are presented. Results of tests on four Sikorsky S-76 horizontal stabilizers and eleven tail rotor spars are also presented. Panels of material used to fabricate the Sikorsky S-76 components that were exposed for six years were tested and results are presented.

Baker, Donald J.↗

NASA NTRS1990

Evaluation of Composite Components on the Bell 206L and Sikorsky S-76 Helicopters

Progress on two programs to evaluate structural composite parts in flight service on Bell 206L and Sikorsky S-76 commercial helicopters is described. Forty ship sets of composite parts that include the litter door, baggage door, forward fairing, and vertical fin were installed on Bell Model 206L helicopters that are operating in widely different climates. Part installation started in 1981 and selected parts are being removed and tested at prescribed intervals over a 10 yr evaluation. Four horizontal stabilizers and eleven tail rotor spars that are production parts on the S-76 helicopter are being tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, materials used to fabricate the parts are being exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. Results achieved from 123,000 hrs of accumulated service on the Bell 206L parts and 53,000 hrs on the Sikorsky S-76 parts are reported. Seventy-eight Bell 206L parts were removed and tested statically. Results of 7 yrs of ground exposure of materials used to make the Bell 206L parts are presented.

Baker, Donald J.↗

NASA NTRS1989

Five year ground exposure of composite materials used on the Bell Model 206L flight service evaluation

Part of the results of a U.S. Army/NASA-Langley sponsored research program to establish the long term-term effects of realistic ground based exposure on advanced composite materials is presented. Residual strengths and moisture absorption as a function of exposure time and exposure location are reported for four different composite material systems that were exposed for five years on the North American Continent.

Baker, Donald J.↗

NASA NTRS1986

Evaluation of composite components on the Bell 206L and Sikorsky S-76 helicopter

A development flight testing status evaluation is presented for composite material structural components used in the Bell 206L and Sikorsky S-76 commercial helicopters, encompassing litter doors, baggage doors, forward fairings, and vertical fins. These flight tests have been conducted in various climatic conditions. The materials used in the fabrication of these components are also undergoing a separate exposure and testing program. Attention is given to results of 73,000 hrs of accumulated flight time on 206L components and 50,000 hrs on S-76 components.

Baker, Donald J.↗