10.14 Stress_Model: 1D Multi-Yield Model

STRESS_1D

Material_name = STRESS_1D

Material_set_number = mset , etc...

The Stress_1D model can only be used with structural beam and truss elements. It allows the axial-stress vs axial-strain to be described as linear or nonlinear (see Fig. 10.12). If nonlinear, a piecewise linear behavior is assumed and the behavior may be prescribed as either elastic or hysteretic.

Note Variable Name Type Default Description

• Keywords Read Method

Material_set_number integer [1] Material set number Numat

Mass_density real [0.0] Mass density

_{Youngs_modulus real [0.0] Young’s modulus E}

_{Poissons_ratio real [0.0] Poisson’s ratio ν}

Modulus_coeff_0 real [0.0] Initial modulus coefficient H₀

Material_type list [elastic] Material type selection

elastic / hysteretic

Activation_time real [0.0] Time at which nonlinearities are activated.

Tension_cutoff list [off] Tension cutoff option

on / off

Cutoff_tension real [0.0] Cutoff in tension

Tension_failure list [off] Tension failure option

on / off

Compression_cutoff list [off] Compression cutoff option

on / off

Cutoff_compression real [0.0] Cutoff in compression

Compression_failure list [off] Compression failure option

on / off

Stress_level_i real [0.0] Stress level

Modulus_coeff_i real [0.0] Modulus coefficient

(cont’d)

(cont’d)

Note Variable Name Type Default Description

• List Read Method

Material data must follow in the form:

< , mat_type (m), icut(m), cutoff_tension(m), cutoff_compression(m),

(stress_level (i, m), modulus_coeff (i, m), i = 1, 5) >

< terminate with a blank record >.

F_i = stress level - i

H_i = modulus coefficient - i

Figure 10.14. Nonlinear Stress Model

Notes . .