Wai Ting Lo et al., (2014) 3
vinyl acetate (EVA) and polyethylene (PE) are the most common material used to
fabricate the orthotic insole due to their structural and mechanical
in this study, the new methods were adopted to measure and evaluate the
physical properties of the insole.
find force deduction performance in the orthotic insole, the test material was
placed in the dynamic load cell and ball bearing was dropped on the test
material from 400mm height through travelling tube.
various equipment was used to evaluate the insole-skin friction properties and
thermal comfort properties.
evaluate and determine the thermal comfort properties, the moisture region and water
vapor transmission rate the standard test methods of ASTM D1909 with a Mettler
LJ16 moisture analyzer and ASTM E96 is used
the percentage of the moisture region was calculated using,
Mwater / Mdry
× 100% ……………Formula
Mwater = mass of the absorbed
Mdry = dry mass of the
water vapor transmission rate was calculated using,
transmission rate = G / (t × A) ……………Formula 4
G = weight change (g)
t = time duration
A = test area (m2)
in this study, experiment was carried out to find coefficient of friction and
shear angle measurement of the insole material by placing pigskin with
deadweight over the test material and pigskin was connected to the Instron
tensile tester with a nylon filament.
And by measuring the maximum force in
which the whole assembly is sliding, the coefficient of friction was
Static Coefficient Mass of the block + mass of the
of = ————————————————— ……Formula 5
Friction Weight required to
Paton et al., (2007) 4
orthotic insole must meet the several performance objectives based on the
patient’s requirement for the successful treatment. The performance objectives
areas of excessive plantar pressure
shock to the musculoskeletal system
plantar tissues shear reduction
fixed foot deformities
and support flexible foot deformities
weight transfer through the static foot in gait
while designing the insole there are six physical properties of the material
should be considered: density, resilience, compressive stiffness, static
coefficient of friction and shear, durability and compression set.
density of the insole should be chosen according to the patient’s requirement.
The low-density material is light in weight and has good shock absorption
capacity. The high-density material will not compress and not suitable for
the diabetic foot patients, the resilience should be low and should have high
of the material should be considered while choosing the insole. The insole
material should have good resistance over the deformation.
friction and shear should be considered, because which acts parallel to the
surface and prevent them from sliding or slipping.
is crucial factor while choosing the material, it is determined by conducting
fatigue test on the specimen. By performing number of cyclic load on the test
specimen to loss its material property on complete material failure.
compression set, the insole material is compressed in given stain or stress to
find the residual constrains of the insole material and time taken to recover
and acceptable degree of freedom.