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Procedia Engineering 150 (2016) 1227 – 1232
International Conference on Industrial Engineering, ICIE 2016
Car Windshield Protection
A.S. Pereverzev*, B.A. Semenikhin
South-west State University, 50 years of October Str., 305040, Kursk, Russia
Abstract
Research findings and design have allowed to develop a perspective way of the car anti-cracker shield protection, which is the
application of the protective pad mounted across the perimeter of the car windscreen and protecting the most vulnerable sections
of the windshield from chips and cracks (glass fixing seats in the back of the car). In the course of work the need for development
of a way of the car anti-cracker shield protection is justified, the required investigation and the calculation are carried out and the
size of the protective pad for a particular car model is determined.
© 2016
2016Published
The Authors.
Published
by Elsevier
Ltd.
©
by Elsevier
Ltd. This
is an open
access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the organizing committee of ICIE 2016.
Peer-review under responsibility of the organizing committee of ICIE 2016
Keywords: Windshield; strength; stress
1. Introduction
Nowadays, the windshield is an integral part of the vehicle structure. Due to its design and location, the
windshield is exposed to a wide variety of loads: wind load, load due to the elastic deformation of the car body, as
well as the impact load by roadside stones. As a result, the windscreen chips and cracks, which negatively affect
visibility and safety, appear [1].
Moreover, defect repair is generally expensive, especially when it comes to crack repair. The use of protective
films can significantly reduce the probability of crack and chips formation in the windshield, but their cost and
installation are quite expensive too [2, 3]. Therefore, the significance of the work is determined by the need for the
safe vehicle operation, as well as the need for development of alternative ways to protect the windshield from
cracking in order to prolong its life. The main objectives of the work are to study strength characteristics of glass
and to design a method to protect the windshield from cracking.
* Corresponding author. Tel.: 89513303875.
E-mail address: Chaser-93@yandex.ru
1877-7058 © 2016 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the organizing committee of ICIE 2016
doi:10.1016/j.proeng.2016.07.122
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A.S. Pereverzev and B.A. Semenikhin / Procedia Engineering 150 (2016) 1227 – 1232
2. The study of strength characteristics of glass
As a rule, the windshield is susceptible to getting cracks irregularly. From a scientific point of view, this can be
justified as follows. The windshield is a plate rigidly mounted on the vehicle body’s perimeter [4, 5]. When the
windshield is exposed to shock loading, it buckles in the affected area, consequently, a wide variety of stress
appears.
The compressive strength of glass is extremely high, but its tensile and flexural strength are significantly lower.
Accordingly, the factor determining generation of a crack in the fixing zone is the bending stress, which is not
constant for glass, as it is for many other materials, but varies depending on the following reasons:
x duration of load;
x schemes of a window supporting: along the contour from 4 or 2 (3) sides;
x stiffness of a window fixing on the support;
x the ratio of length to width of a window [6].
Since the windshield is rigidly fixed on all sides in the vehicle, the bending stress in the glass fixation positions
will be much higher than in its center. It is the excess of the allowable stress that leads to the formation of cracks in
the glass fixation positions in the vehicle body, where its excess is most likely to happen due to the construction [8,
9].
3. Developing a method of protecting the windscreen from cracking
Taking into consideration the aforementioned disadvantages of windshield protection films, main reasons of
formation of chips and cracks on the windshield and discovered windshield weakest areas we have developed a new
way to protect the car windshield, which is the application of the protective pad [10, 11]. The design of the
protective pad is shown in Fig. 1.
Fig. 1. A protective windshield pad.
The engineered protective pad is made as a closed transparent strip, that locates on the perimeter of the
windshield and consists of a wedge-shaped transparent elastic outer layer and an adhesive inner layer.
The protective pad works as follows. With a help of an adhesive layer the blunt edge of the wedge-shaped profile
of the paste is glued to the outer surface of the windshield along its perimeter to in the windshield fixing position in
the vehicle body, and the sharp edge is glued to in the direction to the window center. If a foreign body contact with
the windshield fixation zone, a thicker layer of the elastic material damps the impact energy and thus prevents the
windshield from cracks. The further reduction of the thickness of the protective pad’s elastic layer toward the glass
center and, accordingly, the degradation of its absorption performance are offset by the improved elastic properties
of the windshield in the direction to its center.
This design of the pad helps to protect the glass fixation zones in the vehicle from cracks, as already mentioned,
these zones are most susceptible to cracking. In addition, the designed construction, unlike protective films,
eliminates the need for a protective coating over the entire surface of the windscreen and that is beneficial to the
useful life of a protective pad [12, 13].
A.S. Pereverzev and B.A. Semenikhin / Procedia Engineering 150 (2016) 1227 – 1232
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Due to the small width of the pad, car owners will be able to save money by gluing the pad to a windshield on
their own.
4. Modeling of the protective pad and determination its size
A calculation and design of the protective pad were made for the windshield of Lada-2110 by means of Ansys
software, which allows to model the car windshield and the conditions of its operation, and also identify the
maximum stress that appears due to the impact force on the various sections of the windshield [14]. Diagrams of
maximum stress are shown in Fig. 2.
Fig. 2. (a) The diagram of the maximum stress under the impact force in the upper fixation positions; (b) The diagram of the maximum stress
under the impact force on the bottom corner of fixation positions; (ɫ) The diagram of the maximum stress under the impact force in a side area of
fixation positions; (d) The diagram of the maximum stress under the impact force in the top corner of fixation positions; (e) The diagram of the
maximum stress under the impact force in the lower fixation positions; (f) The diagram of the maximum stress under the impact force in the
center of the glass.
According to a calculation of the program shown in Table 1, application of the same load to the different parts of
a car windshield reveals that the most vulnerable ones are, as was mentioned before, the glass fixation positions
[15].
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A.S. Pereverzev and B.A. Semenikhin / Procedia Engineering 150 (2016) 1227 – 1232
Table 1. The software calculation results
The direction of load
application
Values of the maximum stress, MPa, depending on the distance from the edge of the glass,
mm
10
30
50
70
90
110
130
150
170
190
bottom - center
6,3
11,5
11,7
12,8
13,4
11,9
9,6
7,8
6,4
5,5
up - center
6,9
12,5
15
13,8
11,8
9,6
7,8
6,5
5,3
5,1
side - center
4,4
11,9
15,1
14,8
12,6
10,5
8,5
6,4
5,5
5,2
bottom corner - center
12,2
19,2
14,2
8,6
7,5
7,1
6,6
6,2
5,7
5,3
top corner - center
7,1
12,4
10,3
9,5
9,2
8,6
7,9
6,8
6,1
5,7
Dependency graphs for the stress and the position and direction of load application are shown in Fig. 3. The
graph shows that peak values of the maximum stress in the fixation positions were observed under the impact at
distances of 30 - 90 mm from the edge of the glass. This heterogeneity can be explain by the geometry of the
windshield design [16].
Fig. 3. (a) Dependency graph for the maximum stress and load application place in the direction from the bottom edge to the center; ()
Dependency graph for the maximum stress and load application place in the direction from top edge to center; (c) ) Dependency graph for the
maximum stress and load application place in the direction from the side edge to the center; (d) ) Dependency graph for the maximum stress and
load application place in the direction from the bottom corner to the center; (e) ) Dependency graph for the maximum stress and load application
place in the direction from the top corner to the center.
A calculation was made for the optimum thickness of the elastic layer according to the maximum stress (19.2
MPa at the lower side of fixation positions), and in other parts of the protective pad, due to constancy of the
thickness of the wedge-shaped profile, the safety margin formed at a distance of 30 mm from the edge of the glass.
A.S. Pereverzev and B.A. Semenikhin / Procedia Engineering 150 (2016) 1227 – 1232
1231
Experiments have shown that, using the protective pad from the PET material as an elastic material, the required
thickness of the elastic layer in zones where the peak maximum stress appears will be 1 mm [17]. The dependence is
shown in Fig. 4.
Fig. 4. Dependency graph for the stress and the thickness of the elastic layer of the protective pad.
The graph shows that when the thickness of the elastic layer is 1 mm, the desired value of the maximum stress of
5.2 MPa can be achieved [18].
According to the distribution of the maximum stress, the optimum width would be a distance from the edge of the
glass if the stress overcomes its peak and reach safe values: 130 mm from the upper and lower edges and 130 mm
from the left and right edges. Taking into account the width of the protective pad and the required thickness of the
elastic layer, a wedge-shaped profile of the protective pad will have the dimensions shown in Fig. 5.
Fig. 5. Dimensions of the profile of the protective pad for the fixation positions
On grounds of the performed calculations, the modeled protective pad for the windshield of Lada-2110 will have
the form shown in Fig. 6 [19, 20].
Fig. 6. The protective pad for the windshield of Lada-2110.
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4. Conclusion
The research findings and design have allowed to identify the most vulnerable areas of the windshield. These are
the glass fixation positions in the vehicle body .
By means of Ansys software, a windshield of a particular car was modeled, soft spots of its fixation in the vehicle
body were revealed and appropriate manufacturing materials were selected. All this made possible the determination
of the size of the protective pad.
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