4D-Fatigue Experimental validation of multiaxial and non-proportional fatigue models for structural details present in ship structures
Abstract
Ship structures age during operation. This is mainly caused by fatigue and corrosion. However, aging itself is not the issue. Instead, because retardation up to some extent is allowable, it is all about managing the aging process such that the maintenance and repair costs are minimized and the risks to crew, ships and environment are kept at acceptable levels. Accurately predicting sufficient fatigue lifetime in the design stage is a crucial factor in reducing costs and risk. So far, fatigue design of ship structures is based on results from uni-axial and constant-amplitude tests, whereas all welded joints in these structures are subjected to variable-amplitude loading. In addition, this loading is multi-axial, and even non-proportional for some joints. Such loading may significantly reduce fatigue resistance of these joints and results in premature fatigue cracks. Those cracks, which bring the risks to unacceptable levels, must be repaired and therefore increase the maintenance cost. The problem is that there are no validated methods for fatigue-lifetime assessment of multi-axial, non-proportional, and variable-amplitude loaded welded details in ship structures. The available methods are from ship structures point of view insufficiently validated, i.e. apply for academic base material details, thin plates and/or different materials. Due to this omission, structural engineers cannot adequately design these structures. The goal is to improve this situation by carrying out a numerical and an unique experimental research.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512755
Entities
People
- Miroslaw Kaminski
Organizations
- Delft University of Technology
- Office of Naval Research
- United States Navy