SENSFIB MONITORING CAPABILITIES
The user interface can be configured to show current stress, fatigue accumulation, accelerations and slamming trend as well as sailing conditions in terms of sea state, wind, speed and position.
HULL GIRDER STRESS
The main function of Hull Stress Monitoring systems is to advise the officers onboard on the stress in the main load-bearing longitudinals to avoid overloading, but this is not the only function of a modern HSM system.
Slamming, or hard wave hits, can seriously damage bow plating, and can be difficult to predict from the bridge. A vertical accelerometer in the bow is therefore included in all our HSM systems. In particularly harsh conditions a ship may experience bottom slamming and some of our more extensive systems include sensors to characterize the bow re-entry load. Adding a strain sensor on a double bottom stiffener in the bow is a simple and maintenance-free alternative to bow pressure sensors that require penetration of the hull.
WHIPPING AND SPRINGING
These resonant effects are receiving increasing attention from class societies as contributors to fatigue. SENSFIB HSM software can show users the load due to whipping and springing relative to other loads. Detailed information on these phenomena is also available to the owner onshore for operations and planning.
Along with corrosion, fatigue is an important factor in the wear on a hull but unlike corrosion, it is impossible to inspect for fatigue before cracking starts. With the good accuracy and reliability of fiber optic HSM we are able to monitor the fatigue build-up in the areas near sensors. For the best monitoring of side-shell fatigue we recommend adding strain sensors on longitudinals inside ballast tanks in the waterline amidships.
ICE RESPONSE MONITORING
Warning of floating ice in cold waters can be included in the HSM system by adding strain sensors in the bow waterline.
Non-intrusive monitoring of sloshing loads can be achieved by measuring the stress in the steel structures that support the containment system in LNG carriers or directly on the tank wall.
When integrated in the inspection and maintenance procedures the information from the HSM system provides valuable input to maintenance planning.