Fig. 6.

Components of the stress tensor of the hydroxapatite needles: components a ${\mathit{\sigma }}_{\text{HA},11}^{\text{polyHA}}$, b ${\mathit{\sigma }}_{\text{HA},22}^{\text{polyHA}}$, c ${\mathit{\sigma }}_{\text{HA},33}^{\text{polyHA}}$, d ${\mathit{\sigma }}_{\text{HA},12}^{\text{polyHA}}$, e ${\mathit{\sigma }}_{\text{HA},13}^{\text{polyHA}}$, and f ${\mathit{\sigma }}_{\text{HA},23}^{\text{polyHA}}$ as functions of the needle orientation (defined by angles $\mathit{\vartheta }$ and $\mathit{\phi }$), for constant volume fractions of the macropores ${\mathit{\varphi }}_{\text{macro}}^{\text{congl}}=0.4$ and of bone tissue $f_{\text{bone}}^{\text{congl}}=0$, when feeding the macroscopic stress tensor defined by Eq. (5) into the downscaling relations given by Eqs. (4), (9), and (11) with ${\mathrm{\Sigma }}_{\text{congl},11}=-10$MPa; g – i minimum and maximum values of the stress tensor components for varying macroporosities and bone tissue volume fractions