The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
K F Walker - One of the best experts on this subject based on the ideXlab platform.
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analytical predictions of fatigue crack growth in the lower plate of the f 111 Wing Pivot Fitting fuel flow hole number 58
1998Co-Authors: B J Murtagh, K F WalkerAbstract:Abstract : This report details a comparison of fatigue growth predictions for a fatigue crack in the lower plate of the F-111 Wing Pivot Fitting, adjacent to Fuel Flow Hole No 58. This is a known fatigue critical location and is designated as DI 86. Fatigue analysis using conventional fracture mechanics techniques and empirical retardation models performed by the manufacturer, Lockheed Martin Tactical Aircraft Systems (then General Dynamics), predicted a fatigue life of approximately 57,000 flight hours. An equivalent analysis was conducted using the analytical crack closure code, FASTRAN II, and this resulted in a life prediction of about 25,000 flight hours. Spectrum differences provide a partial explanation. A FASTRAN II analysis using a spectrum based on an in-flight strain measurement system known as AFDAS produced a shorter life again. Further work is underway to quantify the difference in the predictions due to spectrum differences, and that due to analysis techniques.
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comparison of analytical crack growth modelling and the a 4 Wing test experimental results for a fatigue crack in an f 111 Wing Pivot Fitting fuel flow hole number 58
1997Co-Authors: B J Murtagh, K F WalkerAbstract:Abstract : This report details a series of analyses which were performed to develop expertise and evaluate the performance of several fatigue crack growth prediction computer codes. The analyses were performed for the case of a fatigue crack in the lower plate of the F-111 Wing Pivot Fitting, adjacent to Fuel Flow Hole No 58. This location is a known fatigue critical location and is designated as DI 86. Fatigue cracking leading to failure occurred at this location on the A-4 Wing full scale fatigue test after approximately 12,200 hours of testing. An experimentally derived crack growth curve was available from the A-4 Wing test. Analytical models were developed using conventional LEFM software codes (FractuREsearch and AFGROW) and the analytical crack closure code, FASTRAN II. The analysis results were compared with the experimental result and also with the analysis originally performed by the manufacturer, General Dynamics. Consistent with previous work, the analytical crack closure code, FASTRAN II, produced the most consistent and accurate results.
J D Roberts - One of the best experts on this subject based on the ideXlab platform.
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reinforcement of the f 111 Wing Pivot Fitting with a boron epoxy doubler system materials engineering aspects
Composites, 1993Co-Authors: A A Baker, R J Chester, M J Davis, J D Roberts, J A RetchfordAbstract:Abstract Local regions in the D6ac steel F-111 Wing Pivot Fitting suffer plastic deformation during the cold proof test employed to screen out flaws in the steel components of the airframe. This deformation produces residual stresses which can lead to a fatigue cracking problem in service. This paper describes materials engineering aspects of a programme undertaken at the Aeronautical Research Laboratory to develop an advanced fibre composite doubler system aimed at reducing the strain in these regions during the cold proof test and also to reduce cyclic strain during subsequent operation of the aircraft. The doubler system chosen is boron/epoxy (over 120 plies thick) bonded with a structural film adhesive. Aspects described include selection and characterization of composite and adhesive bonding system, doubler fabrication and application technology and evaluation of a representative doubler specimen. Use of the doubler system has been demonstrated to reduce the strain in the critical regions by over 30%, confirming design predictions.
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the development of a boron epoxy doubler system for the f111 Wing Pivot Fitting materials engineering aspects
International Conference on Aircraft Damage Assessment and Repair: 1991; Preprints of Papers, 1991Co-Authors: A A Baker, R J Chester, M J Davis, J A Retchford, J D RobertsAbstract:Local regions in the D6AC steel F111 Wing Pivot Fitting suffer plastic deformation during the cold proof test employed to screen out flaws in the steel components of the airframe. This deformation produces residual stresses which can lead to a fatigue cracking problem in service. This paper describes materials-engineering aspects of a program undertaken at ARL to develop an advanced fibre composite doubler system aimed at reducing the strain in these regions during the cold proof test and also to reduce cyclic strain during subsequent operation of the aircraft. The doubler system chosen is boron/epoxy (over 120 plies thick) bonded with a structural film adhesive. Aspects described include selection and characterisation of composite and adhesive bonding system, doubler fabrication and application technology and evaluation of a representative doubler specimen. Use of the doubler system has been demonstrated to reduce the strain in the critical regions by over 30%, confirming design predictions.
J A Retchford - One of the best experts on this subject based on the ideXlab platform.
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reinforcement of the f 111 Wing Pivot Fitting with a boron epoxy doubler system materials engineering aspects
Composites, 1993Co-Authors: A A Baker, R J Chester, M J Davis, J D Roberts, J A RetchfordAbstract:Abstract Local regions in the D6ac steel F-111 Wing Pivot Fitting suffer plastic deformation during the cold proof test employed to screen out flaws in the steel components of the airframe. This deformation produces residual stresses which can lead to a fatigue cracking problem in service. This paper describes materials engineering aspects of a programme undertaken at the Aeronautical Research Laboratory to develop an advanced fibre composite doubler system aimed at reducing the strain in these regions during the cold proof test and also to reduce cyclic strain during subsequent operation of the aircraft. The doubler system chosen is boron/epoxy (over 120 plies thick) bonded with a structural film adhesive. Aspects described include selection and characterization of composite and adhesive bonding system, doubler fabrication and application technology and evaluation of a representative doubler specimen. Use of the doubler system has been demonstrated to reduce the strain in the critical regions by over 30%, confirming design predictions.
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the development of a boron epoxy doubler system for the f111 Wing Pivot Fitting materials engineering aspects
International Conference on Aircraft Damage Assessment and Repair: 1991; Preprints of Papers, 1991Co-Authors: A A Baker, R J Chester, M J Davis, J A Retchford, J D RobertsAbstract:Local regions in the D6AC steel F111 Wing Pivot Fitting suffer plastic deformation during the cold proof test employed to screen out flaws in the steel components of the airframe. This deformation produces residual stresses which can lead to a fatigue cracking problem in service. This paper describes materials-engineering aspects of a program undertaken at ARL to develop an advanced fibre composite doubler system aimed at reducing the strain in these regions during the cold proof test and also to reduce cyclic strain during subsequent operation of the aircraft. The doubler system chosen is boron/epoxy (over 120 plies thick) bonded with a structural film adhesive. Aspects described include selection and characterisation of composite and adhesive bonding system, doubler fabrication and application technology and evaluation of a representative doubler specimen. Use of the doubler system has been demonstrated to reduce the strain in the critical regions by over 30%, confirming design predictions.
B J Murtagh - One of the best experts on this subject based on the ideXlab platform.
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analytical predictions of fatigue crack growth in the lower plate of the f 111 Wing Pivot Fitting fuel flow hole number 58
1998Co-Authors: B J Murtagh, K F WalkerAbstract:Abstract : This report details a comparison of fatigue growth predictions for a fatigue crack in the lower plate of the F-111 Wing Pivot Fitting, adjacent to Fuel Flow Hole No 58. This is a known fatigue critical location and is designated as DI 86. Fatigue analysis using conventional fracture mechanics techniques and empirical retardation models performed by the manufacturer, Lockheed Martin Tactical Aircraft Systems (then General Dynamics), predicted a fatigue life of approximately 57,000 flight hours. An equivalent analysis was conducted using the analytical crack closure code, FASTRAN II, and this resulted in a life prediction of about 25,000 flight hours. Spectrum differences provide a partial explanation. A FASTRAN II analysis using a spectrum based on an in-flight strain measurement system known as AFDAS produced a shorter life again. Further work is underway to quantify the difference in the predictions due to spectrum differences, and that due to analysis techniques.
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comparison of analytical crack growth modelling and the a 4 Wing test experimental results for a fatigue crack in an f 111 Wing Pivot Fitting fuel flow hole number 58
1997Co-Authors: B J Murtagh, K F WalkerAbstract:Abstract : This report details a series of analyses which were performed to develop expertise and evaluate the performance of several fatigue crack growth prediction computer codes. The analyses were performed for the case of a fatigue crack in the lower plate of the F-111 Wing Pivot Fitting, adjacent to Fuel Flow Hole No 58. This location is a known fatigue critical location and is designated as DI 86. Fatigue cracking leading to failure occurred at this location on the A-4 Wing full scale fatigue test after approximately 12,200 hours of testing. An experimentally derived crack growth curve was available from the A-4 Wing test. Analytical models were developed using conventional LEFM software codes (FractuREsearch and AFGROW) and the analytical crack closure code, FASTRAN II. The analysis results were compared with the experimental result and also with the analysis originally performed by the manufacturer, General Dynamics. Consistent with previous work, the analytical crack closure code, FASTRAN II, produced the most consistent and accurate results.
A A Baker - One of the best experts on this subject based on the ideXlab platform.
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reinforcement of the f 111 Wing Pivot Fitting with a boron epoxy doubler system materials engineering aspects
Composites, 1993Co-Authors: A A Baker, R J Chester, M J Davis, J D Roberts, J A RetchfordAbstract:Abstract Local regions in the D6ac steel F-111 Wing Pivot Fitting suffer plastic deformation during the cold proof test employed to screen out flaws in the steel components of the airframe. This deformation produces residual stresses which can lead to a fatigue cracking problem in service. This paper describes materials engineering aspects of a programme undertaken at the Aeronautical Research Laboratory to develop an advanced fibre composite doubler system aimed at reducing the strain in these regions during the cold proof test and also to reduce cyclic strain during subsequent operation of the aircraft. The doubler system chosen is boron/epoxy (over 120 plies thick) bonded with a structural film adhesive. Aspects described include selection and characterization of composite and adhesive bonding system, doubler fabrication and application technology and evaluation of a representative doubler specimen. Use of the doubler system has been demonstrated to reduce the strain in the critical regions by over 30%, confirming design predictions.
-
the development of a boron epoxy doubler system for the f111 Wing Pivot Fitting materials engineering aspects
International Conference on Aircraft Damage Assessment and Repair: 1991; Preprints of Papers, 1991Co-Authors: A A Baker, R J Chester, M J Davis, J A Retchford, J D RobertsAbstract:Local regions in the D6AC steel F111 Wing Pivot Fitting suffer plastic deformation during the cold proof test employed to screen out flaws in the steel components of the airframe. This deformation produces residual stresses which can lead to a fatigue cracking problem in service. This paper describes materials-engineering aspects of a program undertaken at ARL to develop an advanced fibre composite doubler system aimed at reducing the strain in these regions during the cold proof test and also to reduce cyclic strain during subsequent operation of the aircraft. The doubler system chosen is boron/epoxy (over 120 plies thick) bonded with a structural film adhesive. Aspects described include selection and characterisation of composite and adhesive bonding system, doubler fabrication and application technology and evaluation of a representative doubler specimen. Use of the doubler system has been demonstrated to reduce the strain in the critical regions by over 30%, confirming design predictions.
