Fatigue strength assessment of ship structures, in general, has been performed in accordance with the procedures proposed by classification societies. However, these procedures do not effectively take into account the actual loading and operation conditions that ships experience in their lifetime. Besides, the current trend of building ever larger ships demands more precise and realistic evaluation of fatigue strength, especially in dealing with uncertainties involved in the current simplified evaluation methods.

The newly developed fatigue life evaluation system has adopted a spectral analysis methodology, so that the effects of loading conditions, sea states, sailing sea route, ship speed, wave heading angle and so forth can be more clearly and individually assessed during the initial ship design.

The main features of the system are as follows:
- Fatigue assessment based on sailing routes
- Short-term and long-term stress estimations
- Fatigue damage ratio calculation for each loading condition and sea state
- Flexible data interface with various wave load analysis programs
- Graphic user interface (GUI)

HyFLESS also provides several system-managing tools that help to effectively deal with the large amount of data generated from the spectral analysis and to easily browse the details of the fatigue calculation results.

Other features include:
- Design S-N data manager enabling users to input user-defined data, as well as existing widely used standard data
- Automatic generation of internal and external pressures for FEA
- Three-dimensional viewer of fatigue damage ratios
- Simplified fatigue strength calculation module

HyFLESS has been applied to various types of ships, such as containerships, tankers, VLCCs, LNG carriers and FPSOs, and its reliability and practicality has been proven in actual ship design.