MinUnbalDispNorm Integrator

The MinUnbalDispNorm integrator is a static integration method that uses a minimum unbalanced displacement norm criterion to determine step size.

Description

This integrator is particularly suitable for:

• Nonlinear static analysis with adaptive step size

• Problems with varying degrees of nonlinearity

• Cases where automatic step size control is beneficial

• Analysis with potential numerical difficulties

The MinUnbalDispNorm method attempts to find a suitable load increment by minimizing the unbalanced displacement norm.

Parameters

The MinUnbalDispNorm integrator requires the following parameters:

Parameter	Description	Default	Notes
dlambda1	First load increment (pseudo-time step)	None	Required
jd	Factor for subsequent time steps	1	Optional
min_lambda	Minimum load increment	dlambda1	Optional, defaults to dlambda1 value
max_lambda	Maximum load increment	dlambda1	Optional, defaults to dlambda1 value
det	Flag to use determinant of tangent	False	Optional

Usage Example

# Create a MinUnbalDispNorm integrator with basic parameters
integrator = fm.analysis.integrators.create_integrator("minunbaldispnorm",
                                                dlambda1=0.1)

# Create a MinUnbalDispNorm integrator with custom parameters
integrator = fm.analysis.integrators.create_integrator("minunbaldispnorm",
                                                dlambda1=0.1,
                                                jd=3,
                                                min_lambda=0.05,
                                                max_lambda=0.2,
                                                det=True)