JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 56

APPLICATION medical

According to Haruna et al. (2014) [9],
there is a growing trend in developing
countries for the use of advanced composite material (ACM) in several fields
such as aerospace [10], and construction [11]. Advanced composites are also
a suitable option for biomedical applications such as prosthetic sockets due
to their superior strength-to-weight ratio and excellent biocompatibility [12].
For example, Walbran et al. (2016)
[13] designed a carbon fibre composite
spring joint for an ankle-foot orthosis.
Advanced composites are generally
available in the form of a fabric that can
be formed into a complex surface. They
also provide attractive aesthetics due to
their multiple patterns and colours.
Based on this background, this study
aims to select the most appropriate advanced composite material for a prosthetic arm socket in a developing country. This is a multi-criteria problem that
involves qualitative and quantitative
aspects.
Method
This research follows a particular material selection process that is described
in the flowchart in Figure 1.
The material selection process begins
with a literature study to develop the requirements for the prosthetic sockets,
which are then further explored to obtain criteria and sub-criteria. The next
step is to confirm the resulting criteria
using the Delphi method in the form of
a questionnaire with the help of several
experts. The Delphi method makes it
possible to harmonize the communication process within a group to get
a consensus solution to a complex

Fig. 2: (a) Carbon fibre
specimen for tensile
test; (b) Texalium specimen for tensile test; (c)
carbon Kevlar specimen
for tensile test; (d)
Polinet specimen for
tensile test

Fig. 3: Tensile test result
chart for the different
material alternatives

problem [14]. The experts can approve,
disapprove, or give suggestions as additional criteria or sub-criteria. This step
is done repeatedly until all the experts
reach a consensus. The weighted value of each criterion and sub-criterion
is then calculated in the form of another questionnaire with the help of a
number of respondents. The respondents then compare each criterion and
sub-criterion with a paired comparison
(pairwise) and give a rating to each of
them from a set value scale.
Advanced composite material alternatives are then selected considering
their availability in the area of research.

Fig. 1: The advanced composite material selection process

The alternatives are then put through
a standardized test that corresponds
to the criteria of strength and weight
per unit of volume. Each alternative is
processed into standardized samples
to be tested. The samples are shown
in Figures 2 and 4. The strength criteria are measured by tensile strength
while the weight per unit of volume
criteria are measured by the density of
the material. The tensile test refers to
the ASTM D638 standard, while the
density test refers to the ASTM 792-08
standard. Based on the tests conducted, the tensile strength and density of
each alternatives are represented in
Figures 3 and 5, respectively.
The next step is to calculate the weighted value of each material alternative
based on each sub-criterion. The
quantitative sub-criteria are calculated
using a normalization method with a
maximum and a minimum value to
obtain their weighted value. The qualitative sub-criteria are passed through
a series of normalization and weighing

jec composites magazine / November 2020 / SPECIAL ISSUE Sports, Health & Leisure

JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020