Table 51 comparison of four models discussed above

Table 5.1: Comparison of four models discussed above.
Simulation Models Solid Loss (Watts)
[0 0] 1.08e-5
[0 90] 1.92e-5
[ 0 0 0 0] 2.02e-5
[0 90 0 90] 2.11e-5
As shown in Table 5.1 the solid loss obtained for four layers of simulation model
with 0’s and 90’s fiber orientation is higher compared to other three models. Moreover, the
results suggest that if there are more number of fibers, the output results will also increase.
5.3.2.1 Four Layers Simulation Model with More Number of Fibers.
In these simulation models, there are more numbers of carbon fibers for both the
models with four layers shown in the previous section. The number of carbon fibers is
doubled.

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(a)
(b)
Figure 5.7: Four layers models with more fibers (a) same orientation, (b) 0 and 90
orientation.
Fig 5.7 represents the simulation models with more number of carbon fibers. One
model has all the carbon fibers in the same direction whereas another model has 0 and 90
orientation. The solid loss obtained for all the fibers in the same orientation and 0 and 90
orientation are
5
10 72 . 3
-
× and
5
10 94 . 3
-
× W, respectively. These results are comparatively
higher compared to that of the previous section. This explains that more carbon fiber gives

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higher solid loss. Moreover, the results explain that the results for 0 and 90 orientation is
higher compared to the fiber orientated in the same direction.
5.4 Hypothesis of Interface Heating
Results obtained for different simulation models until now suggest that heating in a
laminate takes place in a very thin area where two plies with different fiber direction meet.
Hence, to verify this hypothesis a series of models with two plies were created and
simulated. One ply with 0 degrees and the other with 90 degrees fibers orientation. Also,
using a fixed coil distance to the welding plane. Adding layers of individual fibers to the
two plies as follows:
1. [- - 90] and [ 0 - - ]
2. [- 90 90] and [ 0 0 -]
3. [90 90 90] and [0 0 0] and so on.
Looking at the ply with a microscope, it was found that there are around 30 layers
of individual fibers in one ply. Therefore, the last simulation model will be [30(90)] and
[30(0)]. If heat generation is less in the plies with respect to the numbers of fibers, it can
be concluded that heating is limited to the fibers close to the interface. If this hypothesis is
correct, simulation modeling will be easy because it will be then limited to only a few
layers of carbon fibers.
Figure 5.8 represents the first simulation model for the hypothesis. In this model,
there are two layers of fibers, 0 and 90 orientation. The fibers are created using cylinders.
The diameter and length of the carbon fibers are 0.07 mm and 5 mm respectively, and the
distance between two fibers in the same layer is 0.07 mm. In addition, the distance between

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the two layers is 0.07 mm. There is a conductive coil on top of the fibers at 6 mm distance
from the plane. The coil has a rectangular cross-section of 1.5 mm x 0.75 mm.