dashboard thermal analysis with hyperworks
TRANSCRIPT
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Description of the problem
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The task of the exercise is to study the:
• temperature distribution
• the structural deformation of the dashboard
surface when part of it is subjected to direct sun
light.
Description of the problem
Material
used:
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Polypropylene
E [Gpa] ν ρ [kg/m3]Thermal
Expansioncoefficient [1/C°]
ThermalConductivity
[W/mC°]
HeatTransfer
coefficient [W/m2C°]
1.8 0.45 946 150 e-6 0.16 25.4
Dashboard property:
– thickness t= 2.5 mm
Steel
210 0.3 7800 1 e-5 73 40
Description of the problem
Loading condition.It is suggested to reach the target following some
intermediate steps:
• to obtain the temperature on the dashboard due to
convection with the inner temperature of the cockpit,
• to apply a heat flux of 400 W/m2 to part of the
dashboard in order to simulate the sun light (heat flows
in the dashboard material by conduction),
• to define a coupled thermo-structural analysis and to
analyse the stress/strain distribution on the dashboard.
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Creation of the model
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Import the geometry
Creation of the model
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Move some surface from dashboard to air tunnel
– [tool-organize]
Creation of the model
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Create the Material and insert the specific
properties
– [card image:MAT1 and MAT4 for thermal properties]
Creation of the model
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Create the “Properties” and assign to the
components
• [card image:PSHELL, choose the material and define
the thickness]
Creation of the model
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Create the mesh and merging the common
nodes
– [2D-automesh, tool-edges]
Creation of the model
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Create the constraint point
– create the master nodes [geom-nodes]
– connect to the dashboard [1D-rigids]
Creation of the model
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Create the convection heat exchange surface
– [analysis-interfaces]
Creation of the model
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Create the internal heat source, creating a constraint node with the specific initial T and assign to to the dashboard
– [geom-node, analysis-constraint, card edit-insert the inner T ]
Creation of the model
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Constraint all the air-tunnel nodes and assign
the initial T
– [analysis-constraints, card edit-insert the T ]
Creation of the model
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Create the load-step and Simulate
Creation of the model
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Create the conduction heat exchange surface,create the flux, update the loadstep adding the flux to the laod and Simulate
– [analysis-interfaces]
– [analysis-flux]
Creation of the model
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Create the constraints for the master nodes.
– [analysis-constraints]
Create a generic load-step for the thermal stress
Simulate
Results
Temperature due to convection with
dashboard made of polypropylene
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Results
Temperature due to convection with
dashboard made of steel
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Results
Temperature due to convection and sun light
with dashboard made of polypropylene
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Results
Temperature due to convection and sun light
with dashboard made of steel
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Results
Strain distribution due to convection and
sunlight with dashboard made of polypropylene
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Results
Strain distribution due to convection and
sunlight with dashboard made of steel
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Results
Stress distribution due to convection and
sunlight with dashboard made of
polypropylene
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Results
Stress distribution due to convection and
sunlight with dashboard made of steel
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Results discussion
Temperature due to convection:
– in both cases, polypropylene and steel, we can see
that the temperature of the dashboard achieved
without the sunlight is 30 C , i.e. the internal
temperature, except for some points in the
polypropylene simulation that achieve a slightly
higher temperature due to maybe a simulation
errors. The difference in the two cases is the
temperature field near the air-tunnel. Because of
the steel has an higher thermal conductivity we can
see an bigger aerea with a temperature ranging
from 10 C (air-tunnel T ) and 30 C (internal T ),
while with poly this boundary area is very limited.
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Results discussion
Temperature due to convection and sun-light:
– again, like in the previous simulation, we ca see
that the steel is better in distribute the heat in the
all surface. the temperature distribution is more
uniform and we have a maximum value of 39 C
– in the poly dashboard the sun light tends to
increase, up to 49 C , the temperature of the upper
part.
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Results discussion
Stress/Strain due to convection and sun-light:
– from the simulation we can see that with steel we
have lower displacement and higher stress near
the constraint points because of the E modulus is
much higher than the poly one.
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But just think to a 2.5mm steel dashboard
without the flexibility in shape of the
polypropylene?? It’s a crazy thing.