# BESO for Beams (karamba)

Component Index > Karamba > Algorithms > **BESO for Beams (karamba)**

### Bidirectional Evolutionary Structural Optimization for beam structures.

## Inputs

Name | ID | Description | Type |
---|---|---|---|

Model | Model | Model to be optimized | Model |

Elem Identifiers | ElemIds | List of identifiers of single elements that take part in the BESO procedure. By default the whole structure is included. | Goo |

Group Identifiers | GroupIds | List of identifiers of groups of elements that take part in the BESO procedure and shall be switched on and off collectively. You can use the names of element sets and regular expressions for defining groups. | String |

LCases | LCases | List of load cases that are considered for BESO | Integer |

Target mass ratio | Target | Target Ratio of remaining mass to initial mass of all elements that take part in the BESO. | Number |

Number of change iterations | nChangeIter | Number of iterations for constantly adding or removing elements in the structure. After that additional iterations (until nConvIter is reached) may follow to reach convergence. | Integer |

Number of convergence iterations | nConvIter | Number of iterations for reaching convergence during which elements can be added and removed. | Integer |

Weighting factor for tension | WTension | Weighting factor for beams under tension. | Number |

Weighting factor for compression | WCompr. | Weighting factor for beams under compression. | Number |

Weighting factor for shear | WShear | Weighting factor for beams under shear. | Number |

Weighting factor for moments | WMoment | Weighting factor for beams under moments. | Number |

BESO Factor | BESOFac | Add/remove n*(1+BESOFac) of the n currently active elements in one half-step. Remove/add n*BESOFac elements in the next half-step. | Number |

Minimum distance between changing elements | MinDist | Minimum distance between elements changed in one step. | Number |

Relative weight limit | WLimit | Limit ratio between the weight of any active element to the mean weight of all active elements. Elements below that limit get removed after the last step. | Number |

## Outputs

Name | ID | Description | Type |
---|---|---|---|

Maximum displacement | Max.disp | maximum displacement [m] of the model after BESO. | Number |

Optimized model | Model | Model after ESO. | Model |

History of the BESO | Hist | Tree of boolean values: For each iteration a list of booleans signals for each element of the model whether it was on or off. | Boolean |

Element is active | Is active | List of boolean values corresponding to each element in the optimized model. True if the element is active. | Boolean |

Distribution of weights | Weights | BESO-weight of each active group in descending order. | Number |