Image based modelling of silicon carbide composites (SiC ... · Figure 4 – Metris X-tek at the...
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Image based modelling of silicon carbide composites (SiC f /SiC) for use in a fusion power plant’s breeding blanket Image based modelling of silicon carbide Image based modelling of silicon carbide composites ( composites ( SiC SiC f /SiC) for use in a fusion /SiC) for use in a fusion power plant power plant’ s breeding blanket s breeding blanket Ll. M. Evans 1 , P. Mummery 1 , S. Dudarev 2 1. University of Manchester, 2. Culham Centre for Fusion Energy 1. University of Manchester, 2. Culham Centre for Fusion Energy Contact details: Mr. Llion M. Evans Phone: +44 (0)161 3063594 E-Mail: [email protected] The first fusion power project to deliver electrical energy to the grid on a continual basis will be DEMO, a prototype fusion energy power plant planned for 2030. This scaled up magnetic confinement reactor plans to deliver 2GW of electrical output. Such output will create a harsh environment requiring materials at the forefront of mechanical engineering, able to withstand such situations and utilising previous experience from the fission community. As well as the reaction chamber, the other key component in a fusion reactor is the tritium breeding blanket. Even though deuterium is plentiful (1 part in 6500 of hydrogen in seawater is deuterium), tritium is rare due to its short half life of ~12 years. Fortunately tritium can be bred by utilising the fast neutrons produced by the D-T reaction in a secondary reaction with lithium. Achieving this would ensure a self sufficient supply of tritium. 7 Li + n (fast) → He + T + n (slow) 6 Li + n → He + T Compared to plasma facing components, this process requires materials with a different set of properties such as: high thermal conductivity, low reaction rate with liquid lithium, ability to retain properties at high neutron doses and tritium hermeticity. Due to its desirable behaviour, Silicon carbide (SiC) is currently being considered as a tube material for containing and transporting the liquid lithium. 1. DEMO – putting theory into practice 1. DEMO – putting theory into practice Figure 2 – Proposed tritium breeding blanket design Figure 1 – Concept for DEMO Materials Performance Centre Faculty of Engineering and Physical Sciences Materials Performance Centre Materials Performance Centre Faculty of Engineering and Physical Sciences Faculty of Engineering and Physical Sciences 2. Constructing a 3D map of the sample 2. Constructing a 3D map of the sample Tomographic reconstruction was performed on a tube made of 3D woven Hi nicalon fibres with CVD SiC matrix to produce a 3D absorption map. This was done using a series of 2D x-ray radiographs taken whilst rotating the sample through 360°. Figure 4 – Metris X-tek at the Henry Moseley Imaging Facility Figures 5 & 6 – Photograph and 2D x-ray radiograph of silicon carbide composite tube The 3D map was converted into a mesh for finite element purposes using Simpleware ScanIP. Figure 3 – Image acquisition method for tomography 3. Benefits of Image Based Modelling 3. Benefits of Image Based Modelling The greatest benefit image based modelling has over traditional methods of creating geometries for modelling is the ability to model a real, rather than idealised, sample. This has two main advantages: 1. Flaws in the manufacturing of the material, such as porosity, cracks or any other manufacturing defects are included in the model. 2. Direct comparison to experimental results can be made, as the modelled sample can also be subjected to laboratory tests. Another benefit of IBM is the ability to model very complex structures that would otherwise be too time-consuming to realistically reconstruct in a CAD program. 0 10 20 30 40 50 60 70 80 90 100 0 0.04 0.08 0.12 0.16 Strain Stress (MPa) Experimental Image-based Analytical Unit cell Figure 8 – Stress/Strain results from previous work at University of Manchester on graphitised composites in perpendicular direction Figure 9 – Section of 3D image of Aluminium foam with around 500 million elements made with tomographical data Figure 7 – Finite element mesh created from reconstructed 3D absorption map 4. Simulating reactor conditions 4. Simulating reactor conditions 5. Future work 5. Future work Currently no material test facilities exist that can reproduce the conditions expected in a fusion reactor. Therefore, computational simulation is a valuable technique used to predict the behaviour of components in such environments. The model must next be validated using experimental data. Following this, the model may be further developed to include a thermal gradient along the length of the tube and pressure within the pores to simulate helium production associated with irradiated SiC. The sample is currently treated as homogeneous material with thermal and mechanical problems being modelled separately. This is due to the computational limitations of a desktop workstation, which requires the data to be downsampled to 25% of its original resolution. It is planned to develop a 100% resolution model using the finite element code ParaFEM running on HECToR, the UK‘s high performance research computer. The exponentially higher number of elements used will allow for a model that will distinguish between fibres and matrix of the composite and thus will account for the material‘s hugely anisotropic behaviour. It will also be possible to run thermo-mechanical coupled problems. Arrangements are being made to irradiate SiC samples in Idaho National Labs‘ Advanced Test Reactor in order to collect properties of the irradiated material. These will be added to the model to simulate the change in behaviour with increased irradiation damage. Figure 10 – Von Mises stress due to pressure caused by flow of coolant In order to model the component behaviour, mechanical and thermal input data must first be collected. These were determined by: nanoindentation and appropriate interfacial tests, laser flash, differential scanning calorimetry and thermal gravimetric analysis, respectively. Using the 2 million element mesh of the SiC tube created by Simpleware ScanIP from tomographical data, a model was constructed in ABAQUS to simulate the pressure applied by the flow of liquid lead- lithium coolant.
Transcript of Image based modelling of silicon carbide composites (SiC ... · Figure 4 – Metris X-tek at the...
Image based modelling of silicon carbidecomposites (SiCf/SiC) for use in a fusion
power plant’s breeding blanket
Image based modelling of silicon carbideImage based modelling of silicon carbidecomposites (composites (SiCSiCff/SiC) for use in a fusion/SiC) for use in a fusion
power plantpower plant’’s breeding blankets breeding blanketLl. M. Evans1, P. Mummery1, S. Dudarev2
1. University of Manchester, 2. Culham Centre for Fusion Energy1. University of Manchester, 2. Culham Centre for Fusion Energy
Contact details:
Mr. Llion M. Evans
Phone: +44 (0)161 3063594
E-Mail: [email protected]
The first fusion power project to deliver electricalenergy to the grid on a continual basis will be DEMO, aprototype fusion energy power plant planned for 2030.This scaled up magnetic confinement reactor plans todeliver 2GW of electrical output. Such output willcreate a harsh environment requiring materials at theforefront of mechanical engineering, able to withstandsuch situations and utilising previous experience fromthe fission community.
As well as the reaction chamber, the other keycomponent in a fusion reactor is the tritium breedingblanket. Even though deuterium is plentiful (1 part in6500 of hydrogen in seawater is deuterium), tritium israre due to its short half life of ~12 years. Fortunatelytritium can be bred by utilising the fast neutronsproduced by the D-T reaction in a secondary reactionwith lithium. Achieving this would ensure a selfsufficient supply of tritium.
7Li + n(fast) → He + T + n(slow)
6Li + n → He + TCompared to plasma facing components, this processrequires materials with a different set of propertiessuch as: high thermal conductivity, low reaction ratewith liquid lithium, ability to retain properties at highneutron doses and tritium hermeticity. Due to itsdesirable behaviour, Silicon carbide (SiC) is currentlybeing considered as a tube material for containing andtransporting the liquid lithium.
1. DEMO – putting theory into practice1. DEMO – putting theory into practice
Figure 2 – Proposed tritium breeding blanket design
Figure 1 – Concept for DEMO
Materials Performance Centre
Faculty of Engineering and Physical Sciences
Materials Performance CentreMaterials Performance Centre
Faculty of Engineering and Physical SciencesFaculty of Engineering and Physical Sciences
2. Constructing a 3D map of the sample2. Constructing a 3D map of the sampleTomographic reconstruction was performed on a tube made of 3D woven Hi nicalon fibres with CVDSiC matrix to produce a 3D absorption map. This was done using a series of 2D x-ray radiographstaken whilst rotating the sample through 360°.
Figure 4 – Metris X-tek at the Henry Moseley Imaging Facility
Figures 5 & 6 – Photograph and 2D x-ray radiograph of siliconcarbide composite tube
The 3D map was converted into a mesh for finite element purposes using Simpleware ScanIP.
Figure 3 – Image acquisition method for tomography
3. Benefits of Image Based Modelling3. Benefits of Image Based ModellingThe greatest benefit image based modelling has over traditional methods of creating geometries formodelling is the ability to model a real, rather than idealised, sample.
This has two main advantages:1. Flaws in the manufacturing of the material, such as porosity, cracks or any other
manufacturing defects are included in the model.2. Direct comparison to experimental results can be made, as the modelled sample can
also be subjected to laboratory tests.
Another benefit of IBM is the ability to model very complex structures that would otherwise be tootime-consuming to realistically reconstruct in a CAD program.
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0 0.04 0.08 0.12 0.16
Strain
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a)
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Image-based
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Unit cell
Figure 8 – Stress/Strain results from previous work at Universityof Manchester on graphitised composites in perpendicular direction
Figure 9 – Section of 3D image of Aluminium foam witharound 500 million elements made with tomographical data
Figure 7 – Finite element mesh created fromreconstructed 3D absorption map
4. Simulating reactor conditions4. Simulating reactor conditions
5. Future work5. Future work
Currently no material test facilities exist that can reproduce the conditions expected in a fusionreactor. Therefore, computational simulation is a valuable technique used to predict the behaviourof components in such environments.
The model must next be validated using experimental data. Following this, the model may befurther developed to include a thermal gradient along the length of the tube and pressure withinthe pores to simulate helium production associated with irradiated SiC.
The sample is currently treated as homogeneous material with thermal and mechanical problemsbeing modelled separately. This is due to the computational limitations of a desktop workstation,which requires the data to be downsampled to 25% of its original resolution.
It is planned to develop a 100% resolution model using the finite element code ParaFEM running onHECToR, the UK‘s high performance research computer. The exponentially higher number ofelements used will allow for a model that will distinguish between fibres and matrix of thecomposite and thus will account for the material‘s hugely anisotropic behaviour. It will also bepossible to run thermo-mechanical coupled problems.
Arrangements are being made to irradiate SiC samples in Idaho National Labs‘ Advanced TestReactor in order to collect properties of the irradiated material. These will be added to the model tosimulate the change in behaviour with increased irradiation damage.
Figure 10 – Von Mises stress due to pressure caused by flow of coolant
In order to model the componentbehaviour, mechanical and thermal inputdata must first be collected. These weredetermined by: nanoindentation andappropriate interfacial tests, laser flash,differential scanning calorimetry andthermal gravimetric analysis, respectively.
Using the 2 million element mesh of theSiC tube created by Simpleware ScanIPfrom tomographical data, a model wasconstructed in ABAQUS to simulate thepressure applied by the flow of liquid lead-lithium coolant.
