The windshield is transparent for most of the solar spectrum. Once the rays of the sun have passed the windshield they will be absorbed by the dark dashboard and heat it up to over 80°C (176°F), which must be compensated by the air conditioning. Now the dashboard itself starts radiating but at longer wavelengths in the thermal infrared and at these wavelengths the windshield is not transparent anymore. The project aims to study the temperature distribution and the structural deformation of a dashboard surface when part of it is subjected to direct sun light. * only the first six pages of the project are presented here. If you are interested to study the rest of this document, please contact me via saeid.ghaffari@studenti.polito.it.

1. Saeid Ghaffari
Professor: Alessandro Scattina
Automotive Engineering - A.Y. 2017-2018
Thermal and Thermo/Structural
Analysis of a Dashboard
Department of
Mechanical and
Aerospace Engineering

2. 2
Everybody knows the situation when a car has been parked in the sun.
Especially the van type cars with large windows become incredibly hot
inside so that it is almost not possible to touch the steering wheel. The
temperatures on the dashboard and the steering wheel can reach over
80°C (176°F), which has to be compensated by the air conditioning.
The windshield is transparent for most of the solar spectrum. Once the
rays of the sun have passed the windshield they will be absorbed by the
dark dashboard and heat it up to unpleasantly high temperatures. Now
the dashboard itself starts radiating but at longer wavelengths in the
thermal infrared and at these wavelengths the windshield is not
transparent anymore.
Department of Mechanical
and Aerospace Engineering
The problem in real world
Automotive Engineering - A.Y. 2017-2018 THERMAL AND THERMO/STRUCTURAL ANALYSIS OF A DASHBOARD

3. The proposed exercise concerns the thermal and thermo/structural analysis of a dashboard. Also the sun light in
parking conditions will be considered.
Purpose of the exercise
Starting from the supplied geometry, the discrete model must be obtained by using 2D shell elements. The
material properties of the polypropylene and steel used for the dashboard are summarized in table
MATERIAL
Young’s
Modulus
(GPa)
E
Poisson
Ratio
Density
(Kg/m3)
Thermal
Expansion
Coefficient
(1/°C)
A
Thermal
Conductivity
(W/m °C)
k
Heat
Transfer
Coefficient
(W/m2 °C)
h
Polypropylene 1.8 0.45 946 150 × 10-6 0.16 25.4
Steel 210 0.3 7800 1 × 10-5 73 40
3THERMAL AND THERMO/STRUCTURAL ANALYSIS OF A DASHBOARD
Department of Mechanical
and Aerospace Engineering
Department of Mechanical
and Aerospace Engineering
Automotive Engineering - A.Y. 2017-2018

4. Loading Conditions
The task of the exercise is to study the temperature distribution and the structural deformation of the dashboard
surface when part of it is subjected to direct sun light. 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
analyze the stress/strain distribution on thedashboard.
4
Department of Mechanical
and Aerospace Engineering
Automotive Engineering - A.Y. 2017-2018 THERMAL AND THERMO/STRUCTURAL ANALYSIS OF A DASHBOARD

5. In the start window click Optic Struct and import the file by clicking Import
solver deck  import geometry. Then locate the file location and click
Import.
Steps for creating the model
5
Department of Mechanical
and Aerospace Engineering
Automotive Engineering - A.Y. 2017-2018 THERMAL AND THERMO/STRUCTURAL ANALYSIS OF A DASHBOARD

6. After importing the object, rename
the two parts as dashboard surface
and duct to easily recognise the
component on the panel.
6
Steps for creating the model
Department of Mechanical
and Aerospace Engineering
Automotive Engineering - A.Y. 2017-2018 THERMAL AND THERMO/STRUCTURAL ANALYSIS OF A DASHBOARD