Loading and Sequential Modeling

Many MPoint analyses consist of a sequence of gravity, construction, excavation, loading, conversion, contact, and large-deformation stages. Preserve the physical order of events because the response may be path dependent.

Save and restore stages

Use model save after each accepted milestone and model restore to start alternative analyses from the same state.

model save 'gravity-equilibrium'

; Later or in another data file.
model restore 'gravity-equilibrium'

Use descriptive names such as gravity, excavated, load-10, and final. Avoid overwriting the only valid initial state.

Excavation and removal

When removing zones or material points, save the pre-removal state, remove only the intended group, reapply or verify active background-node conditions, and allow the model to respond over an appropriate cycle or time interval.

Adding material points

Material points may be generated after an initial stage to represent placement, construction, or an addition. After generation:

  • assign the constitutive model and properties;

  • initialize velocity, displacement, stress, and other required state variables;

  • reapply background-node fixities because new nodes may become active;

  • check overlap with existing material points;

  • save the placed state before loading.

Automatic zone conversion

In a hybrid model, use mpoint hybrid-points to establish coupling and mpoint zone-conversion to control automatic conversion.

mpoint hybrid-points range group 'Coupling'
mpoint zone-conversion interval 10 radius-ratio 3.5

Check conversion frequency and radius sensitivity. Conversion that occurs too late may allow excessive zone distortion; conversion that occurs too early may unnecessarily increase the MPoint region and computational cost.

Restart checks

After every restore or major stage change, verify:

  • active processes and damping settings;

  • large-strain status;

  • gravity and timestep settings;

  • active node fixities;

  • current groups and constitutive models;

  • history continuity and output filenames.