Hysteresis loop definition

@HYSTERESIS_LOOP_DEFINITION {
@HYSTERESIS_LOOP_NAME {LoopName} {
@SENSOR_NAME {SensorName}
@PERIOD {T}
@COMMENTS {CommentText}
}
}

Introduction

Typically, elastomeric and hydraulic devices create hysteresis loops. It is important to evaluate the energy that these devices dissipate during each cycle of operation. This is done by evaluating the area inside the hysteresis loop for one period of the excitation. This area is computed using Simpson's rule over the last period, T, of the hysteresis loop.

Discrete Fourier transforms are performed on the damper stroke and force to evaluate their respective phasing angle.

Notes

  1. The data that defines the hysteresis loop is provided by sensor SensorName. To define a hysteresis loop, this sensor must evaluate a force element stroke, stroke derivative, and force. Hence, it must meet the following requirements.
    1. The sensor is associated with an elastomeric device model and is of type ELASTOMERIC_DEVICE_DATA.
    2. The sensor is associated with an hydraulic device model and is of type HYDRAULIC_DEVICE_DATA.
  2. It is possible to attach comments to the definition of the object; these comments have no effect on its definition.

Example

In this example, a hysteresis loop, HysterLoop, is associated with sensor SensorFeiData, which extracts the data concerning force element interface Fei.

@SENSOR_DEFINITION {
@SENSOR_NAME {SensorEldModlData} {
@OBJECT_NAME {EldModl}
@SENSOR_TYPE {ELASTOMERIC_DAMPER_DATA}
}
}
@HYSTERESIS_LOOP_DEFINITION {
@HYSTERESIS_LOOP_NAME {HysterLoop} {
@SENSOR_NAME {SensorEldModlData}
@PERIOD {1.0}
}
}

Figure 1 shows the hysteresis loop generated by the elastomeric damper. This loop is generated from the data collected by sensor SensorFeiData.

Figure 1. Hysteresis loop generated by the elastomeric damper.

Figure 2 shows the energy dissipated in the elastomeric damper over one period, T. As the transients die out, the energy dissipated per cycle converges to a nearly constant value. Additional figures show the cosine and sine components of the discrete Fourier transform and the damper stroke and force.

Figure 2. Energy dissipated by the elastomeric damper.