NM2D3

$N$-$M$ Interaction Inelastic Section (Nonlinear Hardening)

References

1. 10.1061/JSENDH.STENG-12176

Syntax

section NM2D3 (1) (2...12) [(13) (14) (15) ...]
# (1) int, unique section tag
# (2) double, EA
# (3) double, EI
# (4) double, yielding axial force
# (5) double, yielding strong axis moment
# (6) double, d
# (7) double, isotropic hardening modulus, H
# (8) double, isotropic hardening saturation, s
# (9) double, isotropic hardening decay, m
# (10) double, kinematic hardening modulus, K_b
# (11) double, kinematic hardening base, K_a
# (12) double, linear density
# (13) double, a_i
# (14) double, b_i
# (15) double, c_i

In the above command, parameters (13), (14) and (15) form a triplet and can be appended as many groups as the analyst wishes. The surface is assumed to possess the following form,

$$f=\sum_{i=1}^na_ip^{b_i}m_s^{c_i}-d.$$

For example, the surface $f=1.15p^2+m_s^2+3.67p^2m_s^2-c$ can be expressed as follows.

section NM2D3 (1) (2...12) 1.15 2. 0. 1. 0. 2. 3.67 2. 2.

The only validation implemented is the number of triplets. The command takes $3n$ parameters and interprets them accordingly. Please make sure the definition is correct.