# Flat-Joint Model Properties

The properties of the Flat-Joint Model model are shown below for reference. More detailed information regarding these properties is presented here.

Note

Read-only properties are indicated by (r) at right in this listing.

flatjoint
fj_area f (r)

$$A^{(e)}$$ - area of element $$(e)$$.

fj_cen v (r)

$$x^{(e)}$$ - centroid location of element $$(e)$$.

fj_coh f

$$c$$ - cohesion in units stress with default value 0.0.

fj_cohres f

$$c_r$$ - residual cohesion in units stress with default value 0.0.

fj_egap f (r)

$$g^{(e)}$$ - gap at centroid of element $$(e)$$.

fj_elem i

$$e$$ - set element ( $$e$$ ) to i with default value 1.

fj_emod f (r)

$$E^*$$ - effective modulus.

fj_fa f

$$\phi$$ - friction angle in units degrees with default value 0.0.

fj_force v (r)

$$\tilde{{\mathbf F}}$$ - interface force.

fj_fric f

$$\mu$$ - friction coefficient with default value 0.0.

fj_gap f (r)

$$g_s$$ - surface gap.

fj_gap0 f (r)

$$g_0$$ - initial surface gap.

fj_kn f

$$k_n$$ - normal stiffness in units stress/disp. with default value 0.0.

fj_kratio f (r)

$$\kappa^*$$ - normal-to-shear stiffness ratio.

fj_ks f

$$k_s$$ - shear stiffness in units stress/disp. with default value 0.0.

fj_moment v (r)

$$\tilde{{\mathbf M}}$$ - interface moment.

fj_mtype i (r)

initial microstructural type.

fj_nal i (r; 3D ONLY)

$$N_\alpha$$ - number of elements in circumferential direction.

fj_nr i (r)

$$N_r$$ - number of elements in radial direction (total number of elements in 2D).

$$R$$ - flat-joint radius.

fj_relbr v2 (r)

$${\pmb \theta}_{\mathbf b}$$ - relative bend-rotation as a 2D vector.

fj_resmode i

$$M_r$$ - residual cohesion mode. If $$M_r = 0$$, the shear stress drops to zero. If $$M_r = 1$$, the shear stress drops to the residual value.

fj_rmul f (r)

$$\lambda$$ - radius multiplier.

fj_shear f (r)

$$\tau_c^{(e)}$$ - shear strength in units stress at centroid of element $$(e)$$.

fj_sigma f (r)

$$\sigma^{(e)}$$ - normal stress at centroid of element $$(e)$$.

fj_slip b (r)

$$s^{(e)}$$ - slip state of element $$(e)$$.

fj_state i (r)

$$B^{(e)}$$ - bond state of element $$(e)$$.

fj_tau f (r)

$$\tau^{(e)}$$ - shear stress at centroid of element $$(e)$$.

fj_ten f

$$\sigma_c$$ - tensile strength in units stress with default value 0.0.

fj_track b

tracking state for use when plotting contacts with the specific numeric value with default value false.

user_area f

$$A$$ - set contact area to the constant value f.