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KOTO CsIカロリメータを地震から保護するカバーの設計と製作
Taku YamanakaSeptember 19, 2011
JPS Fall Meeting@Hirosaki
KOTO CsI Calorimeter
2240 2.5cm x 2.5cm
476 5cm x 5cm
50cm long CsI crystals
Finished stacking on Feb. 10, 2011
2
J-PARC KOTOAt the earthquake on March 11, the CsI crystals moved out by ~5mm
3
Purpose of this project
Prevent the crystals from flying out of the cylinder at the NEXT large earthquake
Assumptions
1G horizontal acceleration
4.5g/cm3 x 50cm x 9.8m/s2 = 22kPa side pressure
x3 safety factor = 66kPa
(20t on 2m-diameter surface)
4
Design Requirements
Strong
Light (no crane inside the dry room)
Soft (not to damage crystals)
Limited out-gassing in vacuum
V1 = to be used until the beam time
5
Hard plate?SS400 steel: strength = σmax = 2400kg/cm2
Required thickness = 2cm
weight = 490kg!
6
P = 66kPa
h
a
σmax =3(3 + ν)
8Pa2
h2
7
co /en
cushncfoss sa?rirn
IOuTen ylen/
,-. . .
Cover made of a strong cloth
Structure to keep parabola
shape
Soft cover
Tension and curvature - in case of a string -
8
T
T
θ2
θ1
x
z w [N/m]
Δx
w∆x = T (sin θ2 − sin θ1)
� T (dz
dx(x + ∆x)− dz
dx(x))
w � Td2z
dx2
Tension and curvature- in case of a sheet -
If the sheet has a parabola shape:
9
Cushrutr
cforSSec,t'rtrn
outen ylerV
I
HI +:iJ;r'\,
Hh
Pz = ar2 = a(x2 + y2)P = 4aT
P∆x∆y = T∆y
�dz
dx(x + ∆x)− dz
dx(x)
�+T∆x
�dz
dy(y + ∆y)− dz
dy(y)
�
P � T (∂2z
∂x2+
∂2z
∂y2)
Material for the cover
T = 170kN/m
a = P/4T = 66kPa/ (4x170kN/m) = 0.1/m
bulges out 10cm + offset at the center
10
weight(g/m2)
strength(N/m)
Kevlar Cloth T713 278 1.7x105
Kevlar Cloth T710 315 2.0x105
Teijin Technora MF1500 220 1.7x105
Teijin Technora MF1531 461 3.4x105
How to sew fabrics together
11
and who would be even willing to do it?
Company for fabricating the cover
NI帝人商事 introduced 明大(株)
at Kurashiki, Okayama
http://www.meidai.co.jp/
Makes strong sling belts with Teijin Technora (~100t)
12
Strength test
Make a fabric loop with sewing
Insert two bars inside the loop
Press the two bars apart with force F
Tension = F/2
13
F
5cm
14
15
Sample made by companyTension
~3kN/5cm
= 60kN/m
< 170kN/m (fabric strength)
16
17
The weft slip.Warp only
The weft are squeezed
Sewing thread push the weft
I tried many sewing methods18
19
SolutionMake dead ends for weft
20
10mm
SolutionMake dead ends for weft
21
10mm
Tension ~ 100 kN/m
Final sewing method for Ver.1Bend two fabrics together in Z-shape
Sew 3 locations x 3 times w/ 3mm pitch
Tension = 100 kN/m = 0.6 x 170kN (fabric)
22
DesignSew three 1m wide fabrics => 1 sheet
2 sheets at 45deg
Add sides for securing down to the cylinder
23
The cover24
Securing the cover
Make a loop at the end, and insert a rope
The rope is hold by 9t x 44mm steel bars bolted down to the cylinder
25
idea by Ogahara@Meidai
co /en
cushncfoss sa?rirn
IOuTen ylen/
,-. . .
How to keep the parabola shape
26
27
co /en
cushncfoss sa?rirn
IOuTen ylen/
,-. . .
.(,
*0,
(!, '-brn, l^fls,) N (I,=ll7r !z'lzon")
xz +6##h" 4 d$t>ftR : !fute e"=)Ltt"(r
(eil(: ral-t 1t"tl7' VU'?SJ
7Ar/^,r
PVC pipes
2mm thick Polyethylene plates
Solution = Polyvinyl Chloride pipes
40 different types
379 pieces
28Mr. UesawaVice President
Kyoto Jushi-Seiko
29
30
31
5cm short!
32
So we removed strings for half a circle, extended the side sheet by 7cm, and hand-sewed it.
33
34
Aug. 19, 2011 3AM= T - 6h
What we learned
Do not expect 1mm accuracy for fabrics
By sewing, fabrics takes min(L1, L2)
Prepare an length-adjustment mechanism for fabrics
35
SummaryMade a cover to hold the CsI crystals under 1G horizontal acceleration.
Aramid cloths (Technora, Kevlar) are useful materials for such solutions.
36
明大(株) (縫製)NI帝人商事(株) (縫製社紹介)京都樹脂精工(株) (塩ビパイプ切り)宮崎 (金属加工)秘書の亀井さん (ミシン貸し出し)浅川直也君(4年生) (outgas試験)
Acknowledgements
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