1G.E. Ellwood

Advanced Materials Group 1

• I used the file Luis supplied for a 250GeV beam which was created using a 10x10x500m mesh.

• Geometry of the model was 1000mx100mx3cm.

•A mesh of 20x20x120m.

•I couldn’t use the same mesh size as Luis because that large an aspect ratio would cause the elements to fail shape testing.

•To fit more elements along the z axis I had to reduce the number in x and y.

2G.E. Ellwood

Advanced Materials Group 2

• Due to the amount of elements being used, I decided to conduct only a thermal analysis, initially.

• This will enable me to use Luis’ temperature rise figures as a benchmark.

3G.E. Ellwood

Advanced Materials Group 3

One bunch

• The maximum temperature rise after 1 bunch was 233.32°C.

Slice along the x-z plane at y=5m

4G.E. Ellwood

Advanced Materials Group 4

2 bunches

• Max. temp 466.217°C.

5G.E. Ellwood

Advanced Materials Group 5

Hot Zone in greater detail

In future I will refine the mesh in this region and have a courser mesh over the bulk of the volume.

6G.E. Ellwood

Advanced Materials Group 6

Hottest Node v. Time

0

50

100

150

200

250

300

350

400

450

500

0.E+00 1.E-07 2.E-07 3.E-07 4.E-07 5.E-07 6.E-07 7.E-07 8.E-07 9.E-07 1.E-06

Time (s)

Tem

per

atu

re (

°C)

7G.E. Ellwood

Advanced Materials Group 7

Mesh Sizes

• Prior to using the 20x20x120m mesh (62500 elements), a relatively course mesh of 100x100x500m was used (500 elements).

• This allowed testing of boundary conditions and time step regimes etc. without being computationally expensive.

• This led to temperature rises of only ~11°C per bunch as opposed to ~230 °C on the more refined mesh.

• Previous meshes used for the entire collimator have been of the order of 6mm.

8G.E. Ellwood

Advanced Materials Group 8

Coupled Field Analysis

• The simulation was repeated using SOLID5 coupled field elements.

One bunch,

Temperature rise of 221.654 °C.

A difference of 10.666 °C compared to using thermal elements.

9G.E. Ellwood

Advanced Materials Group 9

2nd Bunch

• Max temp 448.729 °C, difference of 17.488 °C.

10G.E. Ellwood

Advanced Materials Group 10

Hottest Node v. time

The hottest node was the same in each case.

Although the maximum temperature was slightly different, they both displayed a very similar pattern.

0

50

100

150

200

250

300

350

400

450

500

0.E+00 1.E-07 2.E-07 3.E-07 4.E-07 5.E-07 6.E-07 7.E-07 8.E-07 9.E-07 1.E-06

Time (s)

Tem

per

atu

re (

°C)

Coupled Field

Thermal

11G.E. Ellwood

Advanced Materials Group 11

Stress at one element v. time

• Chose the element which contained the node that reached the highest temperature.

• Red crosses indicate time steps

• High concentration of crosses at the 0s & 337ns time steps show where the heat loads were applied.

12G.E. Ellwood

Advanced Materials Group 12

Stress at one element v. time

0.E+00

1.E+08

2.E+08

3.E+08

4.E+08

5.E+08

6.E+08

7.E+08

8.E+08

0.00E+00 2.00E-07 4.00E-07 6.00E-07 8.00E-07 1.00E-06 1.20E-06

Time (s)

von

Mis

es S

tres

s (M

Pa)

13G.E. Ellwood

Advanced Materials Group 13

• Maximum indicated stress is 735MPa. • I have figures of UTS 950MPa and Yield Stress

880MPa for this alloy. – Unfortunately these are room temperature

figures. I haven’t been able to find data for elevated temperatures.

• The time between steps could be too large and data points. – Some higher stresses could have been

missed. • I will perform further analysis to check the time

steps immediately after a beam impact.