instrumentation of breaking glass strobe 6: friday 10am–1pm [email protected] adam seering...
TRANSCRIPT
Instrumentation of Breaking Glass
Strobe 6: Friday 10am–1pm [email protected]
Adam Seering [email protected]
Aubrey Tatarowicz [email protected]
Daniel Hernandez [email protected]
John Hawkinson [email protected]
2
How does glass break?— What ways can we instrument the cracking process?
Concept - What we did - Results - Feasible? - Timeline
3
Making it break!
We tried several ways: Heat on glass + cold water (for thermal shock) Impact from a falling weight BB gun
What can we measure and quantify?
Concept - What we did - Results - Feasible? - Timeline
4
What we want to measure (goals) Is there a consistent shape to the breaking? What is the rate and pattern of deformation and
breakage? How does glass breaking process depend on
glass thickness? Comparison of different measurement techniques
Schlieren, electrically conductive tape, video Effects of different-shaped impact objects
(screwdriver, BB, etc.) What are the effects of temperature?
Concept - What we did - Results - Feasible? - Timeline
5
Investigation of breaking by thermal shock
1mm thick microscope slides,clamped to lab stand
~200°C soldering iron:did not break on instant contact Nor did glass break on
sustained contact 380°C from heat gun
Still glass slide does not break
Concept - What we did - Results - Feasible? - Timeline
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Thermal Shock Works!
1. 380°C from heat gun
2. Release drop of water→ Whether the slide
breaks depends on height of water release
Concept - What we did - Results - Feasible? - Timeline
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Lighting
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Investigation of glass breaking by impact
Thicker sheets of glass — 3/32" (2.4 mm)
Cut sheets to ~2"x8" Taped across apple
boxes Dropped mass
(screwdriver) from different heights
Concept - What we did - Results - Feasible? - Timeline
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Results We can measure crack motion in time
Concept - What we did - Results - Feasible? - Timeline
13 μs per step
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ResultsWe observe flexing of glass, but want a better visuals and instrumentation. Ideas: try projecting a grid onto glass, or view glass edge-on
Concept - What we did - Results - Feasible? - Timeline
11
Lighting to get good results
Back lighting and side lighting work well in order to see cracking, these were used in the images in the previous slides
Top lighting produces a lot of glare
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YES! It is feasible From the trials with slides
We can measure the speed of the crack motion We can break with force and/or thermal shock However, it might be hard to see deformation on slide
since they are so small From the thick sheets,
We can see glass flexing upon impact of blunt object The shattering is more defined — will probably yield
better results than the slides
Concept - What we did - Results - Feasible, YES! - Timeline
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Cost is cheap!
One 8"x10" sheet of glass costs $2 Cut into five 2“ inch slices → $0.40 per slice
Box of slides costs $8 (72 slides) $0.11 per slide
Concept - What we did - Results - Feasible, YES! - Timeline
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Future direction
Thicker sheets are more exciting than small slides: need to reproduce thermal shock using sheets.
We want to try different lighting techniques and camera angles since these factors will be key in being able to extract useful data.
Concept - What we did - Results - Feasible, YES! - Timeline
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Timeline
Week 1
(of Nov. 3)
BB gun, grid reflection, consistency between slides/sheets, pendulum break of slides; heat on the sheets (hotter than heat gun, flame)
Rotate the glass...break on-end.
Week 2(of Nov. 10)
Try Schlieren imaging to capture heat distribution and flexing when breaking
Week 3(of Nov. 17)
Lots of trials of what we found works well. Analyze data.
Week 4(of Nov. 24)
Get beautiful images, still images (this may be the same thing). Analyze more data.
Week 5(of Dec. 8)
Write-up do whatever we need to finish
Concept - What we did - Results - Feasible, YES! - Timeline
Instrumentation of Breaking Glass
Strobe 6: Friday 10am–1pm [email protected]
Adam Seering [email protected]
Aubrey Tatarowicz [email protected]
Daniel Hernandez [email protected]
John Hawkinson [email protected]