Time_curve_data

Data Structure: Time_curve_data

Description

Time curve data structure

Usage

Time_curve_data     NUM=ival   where ival  is the data structure number

Description

Overview

The Time_curve_data data structure allows specification of a magnitude vs. time curve of the form

Time curves may be utilised in conjunction with several different types of operations including:

•Loading - where it acts as a load curve and the magnitude of the load is scaled by the load curve magnitude i.e.

•Supply reservoir boundaries

•Prescribed motion of adaptive refinement region sets

•Prescribed motion of sedimentation horizons

The data is provided as a 2-D table where:

•Row 1 - time as a series of time points in order of increasing time

•Row 2 - the magnitude of the function at each time point

In the following picture it is shown the effect of a time curve (left) on a prescribed displacement of 450 m. With the time curve a transient displacement rate is defined.

Internal Time Curves

Several internal hardcoded time curves are available for assignment to any data structure that requires assignment of a time curve. Those define specific time curve shapes scaled over the duration of the current simulation stage. Those include:

•"Step_ramp" - a linear ramp function that varies from 0 - > 1 over the duration of the stage

•"Step_ramp_down" - a linear ramp function that varies from 1 - > 0 over the duration of the stage

•"Step_scurve" - an S Curve function that varies from 0 - > 1 over the duration of the stage

•"Step_scurve_down" - an S Curve function that varies from 1 - > 0 over the duration of the stage

•"Step_sramp" - a nonlinear ramp function that varies from 0 - > 1 over the duration of the stage. The magnitude gradually increases over the initial 0.25 portion of the stage then transitions to a linear ramp

•"Step_sramp_down" - a nonlinear ramp function that varies from 1 - > 0 over the duration of the stage. The magnitude gradually increases over the initial 0.25 portion of the stage then transitions to a linear ramp

•"Step_constant" - an instantaneous function with a constant magnitude of 1.

Notes

•One Time_curve_data structure is defined for each time curve and a single structure should be defined for each load case

•The keywords Time_curve_data and Load_curve_data are interchangeable

•The magnitude of the time curve may exceed 1 or may be negative