Some ESPI Measurements on the UK TM Stave




























- Slides: 28

Some ESPI Measurements on the UK TM Stave Prototype Static Out-of-plane deflections Normal Modes

Mounting and static-deflection set-up Stave is mounted vertically to an All-Indium panel with temperature sensors both sides Distortion of panel measured due to temperature differential between sides 60 C differential gives ~8 microns bend to panel Capacitive displacement sensors watch front-face silicon in six locations Mounted to indium/aluminium bridges which attach to the indium panel Cooling is supplied by blow-off CO 2 system pipes and cables from rhs Small (relatively) distortion arises on turn-on of cooling, which depends on strain-relief

Invar plate distortion with a ~45 C local temperature differential front-back

Front Invar panel temperatures during cooling test reported Rear Temperatures Differential is never more than 6 C Invar Panel is not driving movements in stave

This is the distortion in the stave caused by applying the CO 2 gas back-pressure. A continuous surface distortion ~10 microns note that top left mounting was ‘incorrect’

The displacement sensors are located as shown: Top 1 Bottom 2 Top 3 Bottom 4 Top 5 Bottom 6 A +ve displacement is movement away from sensor (into page) Conversely a negative is movement towards Left undisturbed the sensors readings remain stable to ~1 mm When cooling or power is applied the stave moves in a way that ESPI does not follow over extended periods (>2 seconds) Movement is jumpy? , but displacement sensors give ‘sensible’ readings and after entire cycle return to same values within a few microns

Data Run with sensor overlapping edges of Modules Time in mins Temp Cooling on = 10 Cooling flow = 5 Power = 120 W Top Left Bottom Left Cooling off Power = 0 Middle Right

Top 1 Bottom 2 Top 3 Bottom 4 Top 5 Bottom 6 motions relative to starting positions Hard to believe the out-of-plane top left fixation is working ‘well’.

Modules found to be debonded in some places The ‘L’ shapes at the bottom edge line up with the edges of modules. When pressed these prove to be detached from the surface of the stave. This data is from 26/1/12 RUN 8 out of plane, when the gas pressure applied

Modules found to be debonded in some places L L L The ‘L’ shapes at the bottom edge line up with the edges of the 5 th, 6 th, 7 th modules from the lhs. When pressed these prove to be detached from the surface of the stave. The module in ‘ 5 th’ position from left moves by about 1/2 mm This data is from 26/1/12 RUN 8 out of plane, when the gas pressure applied

Data Run with sensor overlapping edges of Modules Time in mins Temp Cooling on = 10 Cooling flow = 5 Power = 120 W Top Left Bottom Left Cooling off Power = 0 Middle Right

Data run with sensors displaced to centre of modules Time in minutes Top Left Middle Right Gas On Liquid arrives Cooling Exhausted Cooling Off Bottom Left Middle Right

Sensor 1 – silicon middle in from edge Sensor 2 – silicon middle in from edge Sensor 3 - carbon fibre just off module Sensor 4 – silicon middle edge of module Sensor 5, 6 unchanged 1 2 3 4 5 6 At location 4 silicon seems to be well bonded by visual inspection m Cooling off Cooling P=120 W P=0 W Carbon measure may be affected by proximity to edge of stave - will check

Example of movement in 1. 2 s during period before liquid arrives after cooling is turned on, but before liquid arrives at stave. [? tbc]

Example of change in 1. 2 s during period when P=60 W

Example of change in 0. 8 s during period when P=60 W It is possible that parts are still moving too fast to see at all. Jumps seem another possibility. NB the invar baseplate moves and this is a clear uniform motion (but over much longer time scales than 1. 2 s) - not at all similar to the apparent behaviour of the stave.

Updated Conclusions on Static behaviour o Stave Movement during cooling/powering is Ø typically less than 50 mm out of plane Ø repeatable to within ~fewmm [possibly measurement limitation] Ø Is smooth when the gas pressure applied – surface visible with ESPI Ø Modules are apparently not well bonded ‘locally’ to the stave, causing spurious measurements and ESPI difficulty o Cold-unpowered to cooled is biggest change o Applying power brings the stave partially back to uncooled state o No evidence yet that single edge mounting contributory to size of movement (both edges seem to move the same way & same distance ? )

Stave excited with sound 900 W amplifier, 2 x 300 W speakers [one used as table] Estimate <100 W sound delivered from a range of 1. 5 m Note that wavelength of sound at 60 Hz is around 5 m 240 Hz will be <1. 5 m This is not an ideal excitation method

Measurement with loose top left (bottom right!) mount (Using different speakers) 1 st mode Mode shapes expected if the stave is mounted in a standard configuration and without any loose contact at the locks FEA f 2 / f 1 = 1. 24; f 3/f 2 = 1. 27 2 nd mode FEA 104 Hz 3 rd mode FEA 164 Hz

Measurement with top left fixation tight (bottom right in below) f 2 / f 1 = 1. 24; 1 st mode f 3/f 2 = 1. 27 Approx 60 Hz ~60 Hz Freq 107. 76 108 Hz 2 nd mode 3 rd mode

Stave exhibits other modes, eg: above 118 Hz

The Q of the stave seems high, resonances have a width <4 Hz Q is probably >20 Early Conclusions on Resonant Behaviour o o Stave exhibits resonant behaviour similar to ‘basic’ FEA expectation Lowest resonance is ~58 Hz in current mounting scheme Q is high Behaviour is quite complicated

Approx 118 Hz

Freq above 118 Hz

Freq definitely 118. 71 Hz

Freq >120 Hz

Freq 86 Hz

Freq 107. 76
Completive espi
Phil espi
Christmas carol stave 4 summary
What is a stave
Stave face
Christmas carol summary stave 1
Electrical stave
Stave 5 a christmas carol
Stave core
Bob cratchit quotes
Stave lake water level
What is a stave in literature
A christmas carol stave 4
Electrical stave
Christmas carol stave 1 summary
The ice cream is countable or uncountable
Some trust in horses
Contact forces
They say it only takes a little faith to move a mountain
Fire and ice diamante poem
They say sometimes you win some
Some say the world will end in fire some say in ice
Tư thế ngồi viết
Thẻ vin
Thể thơ truyền thống
Các châu lục và đại dương trên thế giới
Chúa sống lại
Hổ sinh sản vào mùa nào
Từ ngữ thể hiện lòng nhân hậu