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Bespoke Acoustic Emission System for real-time ship hull monitoring for all weather conditions

Periodic Reporting for period 1 - ShipHullSHM (Bespoke Acoustic Emission System for real-time ship hull monitoring for all weather conditions)

Reporting period: 2015-09-01 to 2016-02-29

The European ship repair and maintenance industry suffers from outdated techniques, high labour costs and depressed prices: ship repair operations are inefficient because currently it is impossible to quantify accurately the extent of work required before the ship is in dock. Through our involvement in the EU FP7 project CompHealth , ETS Sistemi Industriali S.r.l. has developed to TRL 6 a non-destructive testing (NDT) system based on an existing RF spiral eddy current method as a defect detection scanner for materials condition assessment during inspection . Tested by project partner Boeing, the scanner is able to inspect large surfaces / panels and accommodate different signal sensors and processing in a built-in unit operated from a laptop. Experience gained from this project and engineering data from the R&D on arrayed SHM sensors have confirmed the significant time and cost benefits of SHM, and has led to the ShipHulISHM NDT solution for continuous inspection, repair and maintenance of steel ship hulls using passive, highly-sensitive Acoustic Emission (AE). ETS Sistemi Industriali S.r.l. is commercially active in this technology and offer advanced AE inspection services as part of their global NDT business.

In the ship industry, structural failure - due to the severe corroding and metal fatiguing environment – is a major cause of the loss of ships, vessels and tankers. Each year over 400 ocean-going ships sink , many as a result of weakened structures due to corrosion and inadequate and poor welding quality . Accidents due to ship failure increased by 113% from year 2011 to year 2013.

Global financial losses are €7.9Bn from lost revenue, ship replacements and insurance compensation due to the sinking of approximately ca. 400 cargo ships each year. An additional €10.5Bn cost is required for repair and maintenance bringing the total to €18.4Bn. In addition, the loss in freight revenue through, on average, 15 days p.a. spent out of service is €9.6Bn p.a.

In order to ensure that the strength of the ship structure is kept safe for operation, regular hull inspections and repairs of paint coatings, excessively corroded plate and fatigue cracks monitoring must be carefully planned and carried out. Dry-dock inspection is mainly done to determine hull plating thickness at key points to extrapolate the extent and rate of corrosion. It is desirable to detect all cracks above a critical size that may propagate, but a complete inspection of an entire hull or just an entire weld is impractical. NDT methods have been widely used in dry-docking services to evaluate the reliability of ship structures; however it is not feasible to inspect the entire hull or even all of the major welds for cracks and defects due to time and cost constraints. Thus the primary purpose of dry-dock inspections is to determine the thickness of the hull plating at strategic points to extrapolate the extent of corrosion. Typically this is done via art ultrasonic thickness measurement . Using current NDT techniques, only 10% of the total weld length is inspected – likely unrepresentative of its condition . Additionally, these tests are manual, slow and expensive. Besides dry-dock inspections, some NDT techniques are adapted for underwater inspection of steel welds . The working conditions for divers are difficult and hazardous - new tankers are double-hulled and the inside hull is not accessible - a major limitation of manual underwater NDT by divers.

The dry-dock techniques require the vessel to be out-of-service, emptied and cleaned, entailing a two week disruption. Each day, dry dock currently costs an average of €50K per day to the operator5. In addition is the cost of the loss (~€7K/day) in potential freight revenue through the ship being out of service. The inspections are carried out manually in dry dock by workers exposed to hazardous conditions - confined spaces, toxic gases, abseiling on ropes and scaffolding. New EC regulations regar
During this Phase 1 project, we have considered market opportunity (size, growth, needs), value proposition, IP strategy, solution technology and financial projections.

Value proposition
The main benefits/development that ShipHullSHM will bring to Europe, in terms of improved competitiveness in the NDT inspection, are:
(i) Introduction of innovative AE technology for the first time with the aim for the EU to be a world leader within the ship repair and maintenance sector
(ii) Perform SHM of critical ship hull welds while the ship is in operation which is unique and will have an immediate and lasting advantage for European ship owner/operators in terms of reducing their downtime and increasing revenue earning availability with an enhanced confidence level as to ship hull structural integrity
(iii) Providing many benefits over dry-dock method, and therefore the hazardous expensive and disruptive dry- dock method can be avoided
(iv) Prevention of ships sinking and lives lost by providing high quality automated inspection, repair and maintenance
(v) Maintenance of the competitiveness of EU SMEs, so that business is not lost to SE Asia and China.
Our aim is to commercialise an innovative ship hull Structural Health Monitoring (SHM) system for use in noise- dominated dynamic and critical environment to improve the safety and profitability of the European ship industry. Our involvement in an EU FP-7 project CompHealth1 has provided us with the tools to bring an Innovative technology in Acoustic Emission (AE) to our core customers within the ship industry. Our main technical objectives are:
• To enhance a novel advanced SHM tool which is completely automated, real-time, continuous, low-cost and permanently mounted Acoustic Emission (AE) monitoring for SHM of ship hull structures whilst in service and throughout their service life. Until further marketing activities are undertaken during the feasibility study, for the benefit of this proposal, we will call this tool ShipHullSHM.
• To prove 100% of the total weld length inspection.
• An improvement of downtime due to reduction in inspection by 1.5 days per year, consequently C81K savings per ship (plus €10,5k in increased freight revenue). Each year 16,550 different types of vessels (ship, oil tanker, etc.) need maintenance and inspection . Deducting the system cost of the C19.3K p.a the potential total savings to ship operators is ca. €1.2 Bn per year, (see section 2.1 Expected Impacts for detailed calculations).
Besides the ship industry, the tool is useful for offshore oil and gas industry which will be our second target market.

Technical developments
The SHM system based on ShipHullSHM will consist of the following subsystems:
• Acquisition and Elaboration system as discussed in section 1.5.
• Sensors with different features dedicated for High Noise Environments and able to identify in critical area:Leaks, Corrosion, Crack propagations.
• Software Analyser able to classify and evaluate with clusters and neural networking different signals reached by sensors.
• On-Line Calibrator to evaluate the activities of sensors at defined intervals
• Parametric sensors that, together with the AE sensors, can help in the analysis and evaluation steps: these could measure temperatures, pressures, thickness of steel and painting, pH, etc.
• Dedicated signal cables and amplifiers
Based on our experience in the EU CompHealth project we will develop the tools and processes innovated there for RF inspection to accommodate AE sensors. This is a standard engineering process but we will need to consider and satisfactorily resolve several important features of the new solution:
• AE sensor array configuration must satisfy end-user needs (this will vary significantly from one type and size of vessel to another);
• Nature of sensory information and data will be different from the CompHealth eddy current information and will require clear definition of specific sampling frequency
Economic benefits
The overall goal of ShipHullSHM is to increase safety and simultaneously increase the efficiency of the European ship repair industry. It will do this by determining the locality of propagating cracks prior to surveys. Subsequent repairs can then be carried out without having to inspect an entire weld or hull area. More efficient repair turnaround means that more work can be carried out within the capacity of existing dry-dock facilities with improved sustainability of the industry. Ship operators will be attracted to purchasing the system because of its extremely low capital cost of €111K - €290K, dependent on ship size, which is only €8K - €20K p.a. assuming a 15 year system life before replacement. Installed on a ship, the system will automatically produce a real-time report on the structural health so that essential repairs can be carried out during planned maintenance schedules, avoiding removal of ships from service for emergency repairs. Because the system will identify early stage damage, repairs can be carried out without costly repairs. Repair and maintenance savings are considered for ShipHullSHM in the first 4 years of commercialisation based on 126 systems installed on average capacity ships, including savings in lost freight revenue. For a nominal ship of 100K DWT the existing repair and maintenance bill based on a unit cost of €8.1/DWT/annum is €810K p.a. Average time out of service p.a. is about 10.5 days, 30% of which will be spent in a single period of several weeks dry dock every 3-5 years. The cost can be seen as rate of €81K per day spread between scaffolding, labour, crane hire, and inspection and repair equipment. The ShipHullSHM target is to reduce these costs and time by 10% i.e. a saving of 0.1 x €810K = €81K per ship p.a. The savings in repair time are 1.5 days per ship so freight revenue can also be increased by 1.5/365 =0.41%. Globally, freight revenue of €333Bn p.a. is carried by a total DWT of 1.3Bn tonnes (€25.6 per DWT). So freight revenue of a 100K DWT ship of €2.56M p.a. is increased by 0.0041 x €2.56M p.a. = €10,500 p.a. The lifetime of the ShipHullSHM system before replacement or progressive upgrading is targeted at 15 years so system capital cost can be counted as 290/15 = €19.3K p.a. Net savings to the shipping operator from a ShipHullSHM installation are €81K + €10.5K - €19.3K = €72K p.a.
Market characteristics: The sensor market for NDT and SHM suppliers is dominated by SMEs which are the first links in a supply chain leading through to service inspection and SHM companies, certification authorities, ship building, ship maintenance/repair companies and the ship owners and operators. This supply chain will be reflected in the consortium for our subsequent innovation project. There are approximately 2,800 European sensor manufacturers, of which over 93% are SMEs. (We have identified one particular SME-AG, with over 642 members – we shall enter into discussions with such SME-AGs during our feasibility project.) Every year about 400 cargo ships sink4, involving global financial losses totalling €7.9Bn from lost revenue, ship replacements and insurance compensation. Global scheduled maintenance and repair costs amount to €10.5Bn p.a.Error! Bookmark not defined., bringing the total to €18.4Bn. In addition the loss in freight revenue through 10.5 days p.a. spent on average out of service for is €9.6Bn p.a. On this basis we believe owners and operators will willingly pay for ShipHullSHM.
Market trends: There are about 15,000 inspection, repair and maintenance SMEs in Europe, of which 933 are marine NDT inspection SMEs who will benefit directly from the projectError! Bookmark not defined.. However, a much larger proportion will benefit because there will be large secondary markets for ShipHullSHM in the in-service SHM of civil engineering structures generally, such as bridges, wind turbine towers, process and energy generation o
ShipHullSHM Concept
SHM Sensors attached to a ship hull