# Significant Contributions

The following list represents the contributions by the UC-SDRL to the area of structural dynamics:

1963 | Use of swept sine frequency response analysis equipment in the study of machine tool structures |

1965-68 | Air Force machine tool studies |

1967 | First modal parameter estimation algorithm for generating modal information from frequency response functions, assuming a proportional damping model |

1969 | Digital Fourier analysis used to measure frequency response functions through impulse excitation |

1970 | Modal parameter estimation algorithm for non-proportional damping model |

1971 | Acoustic signature analysis of castings |

1972 | Animation of modal vectors |

1973 | Development of color display subsystem for data presentation: Waterfall diagram, voice print, sound pressure level mapping, color animated mode shape movies (color gradation used as third dimension) |

1974 | Development of the complex exponential algorithm for real time modal parameter estimation from frequency response functions |

1975 | Modal analysis software including data management and interactive analysis |

1975 | Modal parameter estimation algorithm for multiple frequency response functions (Least Squares Complex Exponential Algorithm) |

1975 | Experimental modal analysis review (literature and interviews) |

1980 | Development of Modal Assurance Criterion for correlation of independent modal vector estimates (Little MAC and Big MAC) |

1980 | Development of dual input, random excitation frequency response function estimation |

1981 | Development of experimental modal analysis technique based upon an intermediate estimate of mass, stiffness, and damping matrices |

1983 | Development of multiple channel random noise source hardware |

1983 | Development of multiple channel signal conditioning hardware (auto-ranging amplifier/filter) |

1985 | Development of Multi-Mac modal parameter estimation algorithm |

1985 | Development of Polyreference Frequency Domain (PFD) modal parameter estimation algorithm |

1986 | Development of Multiple Reference Ibrahim Time Domain (MRITD) modal parameter estimation algorithm |

1987 | Development of new spatial domain modal parameter estimation algorithm, Complex Mode Indicator Function (CMIF) method |

1988 | Development of Unix Modal Program. |

1990 | Development of spatial sine testing hardware, software and parameter estimation algorithms. |

1990 | Calculation of modal filters from experimentally measured data. |

1991 | Development of the "U-Vector" impedance modeling method. |

1991 | Development of the Pertubated Boundary Condition (PBC) test method. |

1992 | Development of the Unified Matrix Polynomial (UMPA) Approach to a common formulation of modal parameter estimation methods. |

1993 | Development and implementation of Modal Filter Based active vibration control methods for complex structures. |

1994 | Development of the "X-Modal" Matlab based, graphical user interface (GUI) modal parameter estimation software for the HP-UX operating system. |

1997 | Development of the Matlab interface to "Plug N Play" drivers for HP/Agilent 143x VXI hardware. |

1997 | Development of Kalman filter computed order tracking software. |

1997 | Development of Matlab based Nearfield Acoustic Holography (NAH) software. |

1998 | Development of the "X-ACQuisition" Matlab based data acqusition software for HP/Agilent 143x VXI hardware. |

1999 | Development of the "X-Modal II" Matlab based, graphical user interface (GUI) modal parameter estimation software for PC and UNIX operating systems. |

2000 | Development of Non-Linear Polynomial Modeling of Multiple Input, Multiple Output (MIMO) Experimental Data |

2002 | Developed 6 DOF Load Cell and Calibration Methods for 6 DOF Loads (Rigid Body Assumption) |

2004 | Developed Experimental Inertia Estimation Method Based upon 6 DOF Interface Loads and Externally Applied Forces and Associated Accelerations (Rigid Body Assumption) |

2006 | Developed Identification Methods for Reduced Order Non-Linear Models from Experimental MIMO Data |

2007 | Developed MIMO Transmissability and MIMO Group Transmissability for Evaluating Structural Integrity |

2008 | Integrated Operational Modal Analysis into the Unified Matrix Polynomial Approach (UMPA) Framework |