Popsicle chain reaction. Problem №17 презентация

Observation of the phenomenon
Is taken away

Qualitative explanation
Motion of one stick leads to non-compensated torque acting other sticks and motion of whole system

Rising mechanism
Из симметрии:

Qualitative explanation
Cobra wave moves because of jet force and decelerates because of elastic force

Speed of the wave front
v
- Shooting out stick forward movement
- Shooting out stick rotational movement
- Young’s modulus measurements

One stick in the chain

Time of stick going out of the chain
time
Stick don’t touch other ones

Time τ
time
Began movement
Don’t touch other sticks

Angular acceleration ε
Shape of deformation

Equation for wave front speed
V doesn’t depend on width a of the stick
V is proportional to thickness b of the stick
V is inversely to length l of the stick

Young’s modulus measurement
A. Papastathopoulos-Katsaros and S. Sardelis. A physical model for the popsicle stick cobra. Emergent Scientist 1, 3 (2017)
displacement, 0,001 mm
Weight P, kN
Experimental data

V vs a

V vs l

Velocity vs material
E – Young’s modulus of the stick
ρ – density of the stick

V vs ϕ

V vs Quantity of sticks and surface

Approximation coefficient

Height of the wave front
H
Force model: balance between
jet, gravity and elastic forces

2-nd Newton law
y

Elastic force
A. Papastathopoulos-Katsaros and S. Sardelis. A physical model for the popsicle stick cobra. Emergent Scientist 1, 3 (2017)

Jet force
v
v

Gravity force
L
β
N

Height formula
H
β
α
From experiments data:

H doesn’t depend on width a of the stick
H is inversely to length l of the stick

Height vs a

Height vs l

Height vs material
E – Young’s modulus of the stick
ρ – density of the stick

V vs Quantity of sticks and surface

Turned chain
- Stable position of the chain

Novelty
2 cases of formation
Increase angle ϕ
Increase thickness of the sticks
dried glue

Conclusion

Bibliography
The physics of a popsicle stick bomb Jer emy Sautel, Andreane Bourges, Aude Caussarieu, Nicolas Plihon, and Nicolas Taberleta (2017)
Popsicle-Stick Cobra Wave Jean-Philippe Boucher,1 Christophe Clanet,1 David Quéré,2 and Frédéric Chevy3 1 LadHyX, UMR 7646 du CNRS, École Polytechnique (2017)
A physical model for the popsicle stick cobra Athanasios Papastathopoulos-Katsaros and Savvas Sardelis (2017)

Boundary conditions
J.-P. Boucher, C. Clanet, D. Quéré, and F. Chevy. Popsicle-stick cobra wave. 2017
breaking limit
limit set by gravity
Young’s modulus of the sticks
Bending stress at rupture of the material
Density of the sticks
thickness of the sticks
length of the sticks

Parametric investigation for Velocity

Parametric investigation for Height

Different shapes

Скорость палочки

Расчет скоростей
A. Papastathopoulos-Katsaros and S. Sardelis. A physical model for the popsicle stick cobra. Emergent Scientist 1, 3 (2017)

Energy transformation

Sticks raises, chain forms
Sticks fly off, chain doesn’t form
Modes of movement

Legend
a – width
b – thickness
l – length

Kinematic Energy VS Δ

One stick motion
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