Page 332 - IJB-10-2

International Journal of Bioprinting Continuous gradient TPMS bone scaffold

Figure 13. Human femur structure. Adapted with permission from ref.43 (Copyright © 2016, Elsevier).

define two points in a linear function as (Y , 1), (Y max , e). The function expression of the periodic parameter is
min
Using the two-point method, the coefficients in the linear shown in Equation XVII. The unknown number expression
function can be obtained, quorum k =(n−1)/(Y max − Y ), in the formula is:
min
ky C
C = −Y min * k + 1. For d y () y () 1 .
y
1
It can be obtained by using the solution of the k ( n 1 )/( Y max Y min )
1

k 1
first-order non-homogeneous linear equation C Y min (XIX)
1
k C 1 1 2
2
()y 2 1 y 0 , quorum C = 2 kY min . Sorting C 2 k Y min
yC
0
0

out the above formula, the following can be obtained: To meet the mechanical requirements of the bone
structure, different models were generated by adjusting
( ky C ) x the input period coefficient (n value) and the minimum

x k 1 C (Y ) and maximum (Y ) cell pore sizes. Three

min
max
( yC 0 ) y (XVII) suitable models, namely G_2x10, G_2x12, and G_4x12,
1
y
2 y
( ky C ) z were selected based on their unit cell sizes. The three

1
z
Therefore, the implicit function expression of the models are shown in Figure 14. The specific parameters
of each model are displayed in Table 2.
optimized structure is:
To verify the mechanical properties of these models,
f(x, y, z) = sin(ω x)cos(ω y) + sin(ω z) cos(ω x) compression experiments were conducted using printed
y
z
x
x
+ sin(ω y)cos(ω z) = 0 (XVIII) samples. To minimize experimental error, each sample
y z
Figure 14. Optimization TPMS gradient structure model.

Volume 10 Issue 2 (2024) 324 doi: 10.36922/ijb.2306