Abstract
Vibration fatigue tests (constant amplitude, zero mean stress) have been carried out on 20 `real size` welded I beam specimens representative of the 60 metre diameter horizontal axis wind turbine rotor manufacture, to investigate the relationship between Non-destructive Testing (NDT) and Fatigue Loading in respect to life. Three areas were looked at which are relevant to the fatigue life of the 60m Blade, using these unstress relieved specimens (simulating on-site fabrication and repair). Firstly, the correlation between NDT determined weld defect geometry and fatigue life was considered. It is concluded that knowing defect sizes, geometry and location does not allow direct prediction of the failure site nor determination of its actual life. It was noted that all the endurances obtained in these tests were significantly better than the BS5400 guide lines, particularly for endurances in excess of 10{sup 7} cycles. Secondly, the effect of infrequent high loads on fatigue life was considered. It was found that excursions up to 20% above `base` bending stress levels, at a frequency of 10{sup 3} cycles in every 10{sup 6} at `base` level, appeared to have no significant effect on life for the two specimens tested. Finally, the efficiency of welded repairs was examined.
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Citation Formats
Baines, P J.
Wind energy fatigue test programme. Report on fatigue strength assessment on weld details.
United Kingdom: N. p.,
1992.
Web.
Baines, P J.
Wind energy fatigue test programme. Report on fatigue strength assessment on weld details.
United Kingdom.
Baines, P J.
1992.
"Wind energy fatigue test programme. Report on fatigue strength assessment on weld details."
United Kingdom.
@misc{etde_10117321,
title = {Wind energy fatigue test programme. Report on fatigue strength assessment on weld details}
author = {Baines, P J}
abstractNote = {Vibration fatigue tests (constant amplitude, zero mean stress) have been carried out on 20 `real size` welded I beam specimens representative of the 60 metre diameter horizontal axis wind turbine rotor manufacture, to investigate the relationship between Non-destructive Testing (NDT) and Fatigue Loading in respect to life. Three areas were looked at which are relevant to the fatigue life of the 60m Blade, using these unstress relieved specimens (simulating on-site fabrication and repair). Firstly, the correlation between NDT determined weld defect geometry and fatigue life was considered. It is concluded that knowing defect sizes, geometry and location does not allow direct prediction of the failure site nor determination of its actual life. It was noted that all the endurances obtained in these tests were significantly better than the BS5400 guide lines, particularly for endurances in excess of 10{sup 7} cycles. Secondly, the effect of infrequent high loads on fatigue life was considered. It was found that excursions up to 20% above `base` bending stress levels, at a frequency of 10{sup 3} cycles in every 10{sup 6} at `base` level, appeared to have no significant effect on life for the two specimens tested. Finally, the efficiency of welded repairs was examined. It is concluded that for the five specimens repaired there was a general reduction in endurance relative to the as-manufactured life but still within the scatter band for all the specimens tests in this programme, so this reduction is not serious. (author).}
place = {United Kingdom}
year = {1992}
month = {Dec}
}
title = {Wind energy fatigue test programme. Report on fatigue strength assessment on weld details}
author = {Baines, P J}
abstractNote = {Vibration fatigue tests (constant amplitude, zero mean stress) have been carried out on 20 `real size` welded I beam specimens representative of the 60 metre diameter horizontal axis wind turbine rotor manufacture, to investigate the relationship between Non-destructive Testing (NDT) and Fatigue Loading in respect to life. Three areas were looked at which are relevant to the fatigue life of the 60m Blade, using these unstress relieved specimens (simulating on-site fabrication and repair). Firstly, the correlation between NDT determined weld defect geometry and fatigue life was considered. It is concluded that knowing defect sizes, geometry and location does not allow direct prediction of the failure site nor determination of its actual life. It was noted that all the endurances obtained in these tests were significantly better than the BS5400 guide lines, particularly for endurances in excess of 10{sup 7} cycles. Secondly, the effect of infrequent high loads on fatigue life was considered. It was found that excursions up to 20% above `base` bending stress levels, at a frequency of 10{sup 3} cycles in every 10{sup 6} at `base` level, appeared to have no significant effect on life for the two specimens tested. Finally, the efficiency of welded repairs was examined. It is concluded that for the five specimens repaired there was a general reduction in endurance relative to the as-manufactured life but still within the scatter band for all the specimens tests in this programme, so this reduction is not serious. (author).}
place = {United Kingdom}
year = {1992}
month = {Dec}
}