Vibration test system and method for structures

A vibration test method for structures in which a vibration exciting means vibrates a real model portion that is a portion of a structure to be assessed, a load measuring means measures a load to be imposed on the real model portion by the vibration exciting means, and a computer receives a numerical model that represents a numerical model portion of the structure to be assessed other than the real model portion, also receives a load value measured by the load measuring means, and produces a command signal, which is transmitted to the vibration exciting means, according to the received numerical model and load value, wherein:

• a command displacement calculating means calculates a displacement, which is made by the real model portion in a predetermined time after completion of measurement by the load measuring means, according to the load value measured by the load measuring means and an external force value;
• a command signal producing means produces a command signal, which is transmitted to the vibration exciting means, using as a target value the displacement calculated by the command displacement calculating means;
• and
• a step control means controls the vibration exciting means, load measuring means, command displacement calculating means, and command signal producing means so that they will act cyclically, wherein:
• for calculation of the displacement made by the real model portion, the command displacement calculating means uses an αOS method to for time integration to solve a vibrational equation that provides a displacement;
• and
• an equilibrium equation is solved based on an increment of the solution of the vibrational equation obtained at each time step from the solution thereof obtained at the previous time step.

A program allowing a computer, which receives a load value measured by vibrating a real model portion that is a portion of a structure to be assessed and also receives a numerical model that represents a numerical model portion of the structure to be assessed other than the real model portion, to act as:

• a command displacement calculating means for calculating a displacement, which is made by the real model portion in a predetermined time after completion of measurement by a load measuring means, according to the load value and a predefined external force value, for using an αOS method for time integration to solve a vibrational equation that provides a displacement, and for solving an equilibrium equation on the basis of an increment of the solution of the vibrational equation obtained at each time step from the solution thereof obtained at the previous time step;
• a command signal producing means for producing a command signal, which is transmitted to the vibration exciting means, using as a target value the displacement calculated by the command displacement calculating means;
• and
• a step control means for controlling the vibration exciting means, load calculating means, command displacement calculating means, and command signal producing means so that they will act cyclically.