# Presentation: 897493

## The design studyof the vacuum system elements(KOPIO experiment) 

- V.Demitchev, A.Timofeev
- (*RDP Corp. KOMPOZIT, Korolev*)

- The design studyof the vacuum system elements(KOPIO experiment)

## Geometry. General View

- Lid

- Pipe

- Ribs

## FE-Analysis Models

-   Three geometry models of the pipe-lid connection have been used in the Finite Element Structural Analysis (FE-Analysis): GA - the joint without any additional intermediate element; GB - the joint thru an intermediate conic surface; GC - the joint thru an intermediate “horn” surface.

**GC** – connection

**GA **– connection

**GB **– connection

-  Three sets of thickness for the lid, pipe and ribs have been considered. Values of these thickness (**TS1, TS2 and TS3) **are shown in** **table on next slide.

## The basic parameters of models

| Thickness Set (TS) | Lid, mm(inch) | Pipe, mm(inch) | Rib, mm(inch) |
| --- | --- | --- | --- |
| TS1 | 12.7 (1/2) | 6.35 (1/4) | 9.525 (3/8) |
| TS2 | 6.35 (1/4) | 6.35 (1/4) | 9.525 (3/8) |
| TS3 | 8.89 (~1/3) | 8.89 (~1/3) | 8.89 (~1/3) |

| Materials | Modulus of Elasticity, E [GPa] | Poisson’s Ratio,  | Yield Limit, [MPa] | Radiation length X0,[cm] |
| --- | --- | --- | --- | --- |
| Be Alloy (32%Be-68%Al) | 135 | 0.20 | 500 | ~ 17 |
| Carbon-plastic composite (65%C-35%Plastic) | 90 | 0.35 | 800 | ~ 20  |

| Parameter | Description | Value, mm (inch) |
| --- | --- | --- |
| D_c | The lid diameter | 3200 (126.0) |
| S_c | The lid sagitta | 254 (10) |
| W_p | Width of the pipe cross-section | 1778 (70) |
| H_p | Height of the pipe cross-section | 228.6 (9.0) |
| H_r | Height of ribs | 152.4 (6 ) |
|   Dx_r | Distance between ribs | 178 (7.0) |

## FE-Analysis (the stress distribution) 

**V1**: Von Mises Stress [MPa]       SEQV_max = 330 MPa

**V2:** Von Mises Stress [MPa] SEQV_max = 154 MPa

- Critical zone P1

- Critical zone P2

- Two versions of FE-Analysis have been done for each combination of the geometry model and thickness: first one for a free pipe end (**V1**), the second one for a fixed pipe end (**V2**).

- A typical example of a stress distribution with two critical zones

## FE-Analysis (displacements)

**V1:** USUM_max = 2.17 mm

**V2:** USUM_max = 1.91 mm

- A typical example of a maximum displacement (GA, TS1)

## FE-Analysis (the pipe displacements)

- V1

- Uz = -1.23

- Uz = -0.05

- V2

- V1

- Uy = ± 1.31

- V2

- Uy = ±1.34

- Longitudinal displacements UZ [mm]

- Vertical (Flexure) displacements UY [mm]

## Summary Results of FE-Analysis

**TS1:  t_cover = 1/2,  t_pipe = 1/4,  t_ribs = 3/8 inch**
**TS2:  t_cover = 1/4,  t_pipe = 1/4,  t_ribs = 3/8 inch **
**TS3:  t_cover = 1/3,  t_pipe = 1/3,  t_ribs = 1/3 inch**

| Model | Stresses [MPa] for V1/V2 |  | Max Displacements [mm] for V1/V2 |  |  |
| --- | --- | --- | --- | --- | --- |
|  | P1 zone | P2 zone | UZ (pipe) | UY (pipe) | USUM |
| Be Alloy (32%Be-68%Al) |  |  |  |  |  |
| GA_TS1 | 331 / 103 | 130 / 154 | 1.22 / 0.05 | 1.31 / 1.34 | 2.17 / 1.91 |
| GB_TS1 | 121 /  83 | 113 / 147 | 1.00 / 0.06 | 1.31 / 1.34  | 2.11 / 1.99 |
| GC_TS1 | 130 /   80 | 110 / 144 | 1.04 / 0.05 | 1.31 / 1.34 | 2.07 / 1.89 |
| GB_TS2 | 312 / 157 | 95 / 135  | 2.56 / 0.07 | 1.31 / 1.34 | 4.88 / 3.98 |
| GB_TS3 | 202 / 105 | 70 /  99 | 1.40 / 0.05 | 1.20 / 1.22  | 3.15 / 2.67 |
| Carbon-plastic composite (65%C-35%Plastic) |  |  |  |  |  |
| GB_TS3 | 191 / 110 | 66 / 93 | 2.27 / 0.06 | 1.79 / 1.84 | 4.48 / 3.85 |

## Conclusions

- For all design variants of the lid-pipe system, the fixed end of a pipe allows to decrease the maximum displacements of pipe and to reduce also the stress of lid in critical zones (P1, P2) up to acceptable values.
- The base variant of the lid-pipe design of the vacuum system (Beryllium alloy with thickness of 1/2”) can’t be made due to technological reasons - the today technology and the equipment allow to weld sheets of Beryllium alloy with the thickness up to 1/4”.

## Conclusions

- The variant of the lid-pipe design with Beryllium alloy of the thickness of 6 mm and with the conic joint of lid-pipe can be made on the modernized technological equipment. The estimated cost of this variant will be more than $2M, period of manufacturing will be 3 years. But, two comments have to be done for this version:
-       - Even for this thickness of Beryllium alloy, ribs on the beam pipe will be soldered by silver, but not welded, because the existing technology allows to weld only an end-to-end shape, but not T-shape.
-       - Opportunity of appearance of micro-cracks in the welded seams because of cyclic loading (vacuum - atmosphere). It will demand an additional polymeric covering on the product surfaces.

## Conclusions

- However, the today technology allows to produce the alternative variant of the lid-pipe design with a carbon-plastic composite of the thickness of 1/3” and with the conic joint of lid-pipe, which provides a safety factor almost 7 and the radiation thickness of  0.05X0. The estimated cost of this variant will be ~ $600K, period of manufacturing will be 2-3 years.

## Schedule and the cost estimation for production of the composite version

| Activity | Description of activity  | Schedule of activity  | Cost (k$) | Results of activity  |
| --- | --- | --- | --- | --- |
| 1. Prototyping | Development of the manufacturing technique;
Production of the special equipment for the manufacturing of the mockup samples in a 1/5 scale;
The manufacturing of 5 mockup samples in a 1/5 scale;
The vacuum test of the mockup samples;
The out-gassing test of the mockup sample;
The test for the complete corrupting of sample by pressure. | 0,5 year,
End of 2003.  | 50 | The documentation for production of the full-scale sample.
Five 1/5 – scale samples.
The test report. |
| 2. Development of technology for production of the full-scale samples | Development of the manufacturing technique for production of the full-scale samples;
Production of the special equipment for the manufacturing of the full-scale samples;
The manufacturing of 2 full-scale samples;
The vacuum and out-gassing test of the full-scale samples;
The test for the complete corrupting of one sample by pressure.  | 1.0 year, 
End of 2004.  | 400 | The corrected technology documentation for production of the final full-scale sample.
Two full-scale pre-production samples.
The test report. |
| 3. Production of the final set of the lid-pipe system  | The manufacturing of the final set of full-scale lid-pipe system.
 | 0,5 year,
July 2005.  | 125 | The final set of the lid-pipe system.
 The test report.
The technical documentation.  |
| 4. Delivery in BNL | Production of special package box, custom procedures, shipping to BNL. | 2 months,
Fall of 2005. | 25 | The shipping documentation  |