TSC developed the practical use of magnetostrictive method for strain measurement and it is embodied in the StressProbe instrument.

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Owen King
5 years ago
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1 TSC StressProbe

StressProbe Background OVERVIEW OF TECHNIQUE Magnetisation of ferromagnetic materials such as iron and mild steel have an interaction with elastic strain called magnetostriction, that is, spontaneous

2 StressProbe Background OVERVIEW OF TECHNIQUE Magnetisation of ferromagnetic materials such as iron and mild steel have an interaction with elastic strain called magnetostriction, that is, spontaneous lattice strain resulting from the alignment of atomic magnetic moments with magnetically ordered regions called domains. TSC s StressProbe is based on the magnetostriction method which is based on measurement of permeability and magnetic induction in ferromagnetic material. TSC developed the practical use of magnetostrictive method for strain measurement and it is embodied in the StressProbe instrument.

3 StressProbe background (2) StressProbe The StressProbe measures changes in permeability and induction using an inducing coil to magnetise the region of interest and small sensing coils to measure changes in the magnetic field close to the surface. There is no theoretical solution for predicting the change in material properties and therefore the application of the StressProbe to measure strain in ferromagnetic material relies on the development of operating procedures and calibration procedures for each material under investigation. TSC develops probes and procedures to enable the use of the equipment for different application areas.

4 REQUIREMENT FOR DEMAGNETISATION The StressProbe measures changes in permeability and magnetic induction of a material. These measurements need to be converted into strain value so that the engineer can use them. A unique calibration curve is therefore required. During the calibration process the measured values produce different loading and unloading paths due to load hysteresis. A demagnetisation yoke (TSC Demag) is normally fitted over the probe and is controlled by the software. This provides the controlled harmonisation of the material. The result is to virtually eliminate the hysteresis effect and make it possible to produce a unique calibration curve.

5 INTRODUCING THE StressProbe FIELD SYSTEM

6 StressProbe Field System FEATURES Instrument built inside a Peli case. Input power 110V AC; Demag facility requires 1.0A power. Probes: Size, shape and number of sensors inside the probe are application specific. System requires software to be installed. Two types are available: Mapping Software where the probes make measurements on the surface to be inspected Monitoring Software is used when probes are fixed on the surface of a structure and connected to an instrument. Monitoring is normally periodic. For underwater applications the demag yoke has been miniaturised and is housed inside the probe

7 StressProbe Field System APPLICATION FEATURES StressProbe can be used on ferromagnetic steel. Chemical composition influences domain movement. Carbon steels give the best response - domains move easily. Steels that are known as precipitation hardening steels have a lower response. Generally higher strength (lower carbon) steels give poorer responses. StressProbe can be used as a pick and place strain gauge. StressProbe can be deployed topside and underwater, by diver or ROV. StressProbe makes measurements of the total strain in the component at the time of inspection.

StressProbe Field System SOLUTIONS TO INDUSTRY StressProbe was used on civil engineering structures most notably the Guardian Headquarters London and Amex HQ Brighton in place of damaged strain

Therefore with the correct procedure in place StressProbe can deliver information on the load/strain in a structure on-site.

8 StressProbe Field System SOLUTIONS TO INDUSTRY StressProbe was used on civil engineering structures most notably the Guardian Headquarters London and Amex HQ Brighton in place of damaged strain gauges. A significant advantage over strain gauge is that StressProbe measures the total strain at the time of inspection unlike strain gauges which require an event to take place. Therefore with the correct procedure in place StressProbe can deliver information on the load/strain in a structure on-site. TSC developed probes and methodology to allow London Underground to evaluate strain distribution in cast iron tunnel liners built end of 19th century beginning of 20th century using a non-contacting NDT technique instead of cutting out strain gauged 6 cores from the cast iron liner.

StressProbe Field System SOLUTIONS TO INDUSTRY (2) TSC developed probes and procedures and

tightening on a number of repair cans on Claymore platform.

9 StressProbe Field System SOLUTIONS TO INDUSTRY (2) TSC developed probes and procedures and successfully evaluated the load distribution on the entire locking pins network on BP Harding Platform Legs. StressProbe was used successfully as a QA tool to confirm the underwater campaign of bolt tightening on a number of repair cans on Claymore platform. StressProbe survey was initially carried out for Elf and later on for the new owners Talisman Energy. SMART Plugs StressProbe was used to evaluate the highest strain levels at points of contact with the internal pipe surface.

StressProbe Value Calibration of the underwater probes used for load measurement on mooring chains.

10 StressProbe Application Example MOORING CHAINS Three full size mooring chain links from FPSO Brasil were supplied io conduct the calibration of the probe prior to the offshore campaign. StressProbe Value Calibration of the underwater probes used for load measurement on mooring chains. Calibration curve R3S mooring chain Load in tonnes

StressProbe Application Example MOORING CHAINS (2)

deployed system in the Roncador Field, Offshore

11 StressProbe Application Example MOORING CHAINS (2) Offshore trials conducted on FPSO Brazil with diver deployed system in the Roncador Field, Offshore Brazil. Water depth 1,360m average. Three bundles of 3 chains. 114mm diameter chain Grade R3S Studless. Load measurement was successfully carried out on all 9 mooring chains

StressProbe FOR IN LINE AXIAL STRAIN MEASUREMENT TSC and Baker Hughes Canada jointly developed the StressProbe technique for deployment on a Smart Pig to provide axial strain measurement during

12 StressProbe FOR IN LINE AXIAL STRAIN MEASUREMENT TSC and Baker Hughes Canada jointly developed the StressProbe technique for deployment on a Smart Pig to provide axial strain measurement during in-lineinspection of oil and gas transmission pipelines. Baker Hughes, a GE Company have a Worldwide Exclusive licence to this development and earlier this year unveiled the AXISSTM tool for in-line axail strain measurement technology. The AXISSTM tool can be deployed on pipelines. A large number of inspection runs have successfully been completed in Canada, USA and Central America.

13 AXIAL STRAIN TOOL- DATA SHOWS CHANGE IN AXIAL STRAIN ON A SLOPE BEFORE & AFTER STRAIN RELIEF IPC st ILI inspection run - green (before strain relief) 2nd ILI inspection run - red (after strain relief)

14 COMPARISON OF AXISSTM DATA WITH STRAIN GAUGE DATA IPC Membrane (StressProbe) 1250 Bending (StressProbe) Strain (m/m*10^6) Membrane (Strain Gauge) Bending (Strain Gauge) Chainage (m)

15 StressProbe SYSTEM INFORMATION FOR UNDERWATER APPLICATIONS Sensor specification Sensors in the probes provide readings averaged over a 5mm diameter, this is comparable with strain values measured using strain gauges. Measurement Resolution - 10µɛ Measurement Accuracy - Accuracy values quoted are based on a calibration process carried out on a representative sample from the structure under inspection. Representative sample 200µɛ for absolute strain value - Static Identical sample 50µɛ - Static 10µɛ for variation in load - Dynamic Application Area Normal application area is in the elastic range of the material. The stress fields that can be evaluated using the StressProbe at any given location is surface stress field i.e. a 2D strain distribution, the same as strain values reported by strain gauges. Important Note - unlike strain gauges StressProbe provides a measure of the total strain value at the time of inspection.

16 StressProbe SYSTEM INFORMATION FOR UNDERWATER APPLICATIONS (2) System Features The system can be retrofitted to any structure. Unlike a strain gauge, one can replace a probe and continue to make measurements without losing the baseline value. Data is stored electronically. StressProbe for Monitoring Stability/Drift characteristic Sensors are installed to compensate for temperature and drift. Significant R&D has been carried out in this area but to date this has not been implemented at TSC as there has not been a requirement.

17 StressProbe SYSTEM INFORMATION FOR UNDERWATER APPLICATIONS (3) Deployment The StressProbe can be used subsea and in the splash zone. The StressProbe can be deployed by diver or ROV. Power consumption - Depends on the application and demagnetisation requirement. Sensor Output Analogue output. Communication Options available for any type of communication on board the unit RS232 & RS 485 also USB & Bluetooth. System Dimensions Probes are manufactured to suit the geometry of the area of application. This also applies to the number of sensors in each probe, single probe or array probes. Instrument is based on using a 6 stainless steel bottle, Length 200mm and can be rated for water depths up to 2000m. Cost There is no off the shelf product, cost will depend on application. EX-Rated The system is NOT Ex-Rated.

18 StressProbe TECHNOLOGY BENEFITS StressProbe measures the total strain effect at the time of inspection. StressProbe makes rapid measurements and produces clear user-friendly data. Can be retrofitted to existing structures. Non-contacting strain measurement through coatings is possible up to 7mm in thickness. Successful deployment in harsh and underwater environments. Manual or remote deployment. Can be permanently installed for periodic monitoring. Highly versatile and requires minimal surface preparation.

RAMSTM. 360 Riser and Anchor-Chain Integrity Monitoring for FPSOs

RAMSTM. 360 Riser and Anchor-Chain Integrity Monitoring for FPSOs RAMS 360 Riser and Anchor-Chain Integrity Monitoring for FPSOs Introduction to RAMS Tritech s RAMS is a 360 anchor-chain and riser integrity monitoring system for Floating Production Storage and Offloading